Tag Archives: Raspberry Pi Resources

OpenVX API for Raspberry Pi

Post Syndicated from Alex Bate original https://www.raspberrypi.org/blog/openvx-api-for-raspberry-pi/

Raspberry Pi is excited to bring the Khronos OpenVX 1.3 API to our line of single-board computers. Here’s Kiriti Nagesh Gowda, AMD‘s MTS Software Development Engineer, to tell you more.

OpenVX for computer vision

OpenVX™ is an open, royalty-free API standard for cross-platform acceleration of computer vision applications developed by The Khronos Group. The Khronos Group is an open industry consortium of more than 150 leading hardware and software companies creating advanced, royalty-free acceleration standards for 3D graphics, augmented and virtual reality, vision, and machine learning. Khronos standards include Vulkan®, OpenCL™, SYCL™, OpenVX™, NNEF™, and many others.

Now with added Raspberry Pi

The Khronos Group and Raspberry Pi have come together to work on an open-source implementation of OpenVX™ 1.3, which passes the conformance on Raspberry Pi. The open-source implementation passes the Vision, Enhanced Vision, & Neural Net conformance profiles specified in OpenVX 1.3 on Raspberry Pi.

Application developers may always freely use Khronos standards when they are available on the target system. To enable companies to test their products for conformance, Khronos has established an Adopters Program for each standard. This helps to ensure that Khronos standards are consistently implemented by multiple vendors to create a reliable platform for developers. Conformant products also enjoy protection from the Khronos IP Framework, ensuring that Khronos members will not assert their IP essential to the specification against the implementation.

OpenVX enables a performance and power-optimized computer vision processing, especially important in embedded and real-time use cases such as face, body, and gesture tracking, smart video surveillance, advanced driver assistance systems (ADAS), object and scene reconstruction, augmented reality, visual inspection, robotics, and more. The developers can take advantage of using this robust API in their application and know that the application is portable across all the conformant hardware.

Below, we will go over how to build and install the open-source OpenVX 1.3 library on Raspberry Pi 4 Model B. We will run the conformance for the Vision, Enhanced Vision, & Neural Net conformance profiles and create a simple computer vision application to get started with OpenVX on Raspberry Pi.

OpenVX 1.3 implementation for Raspberry Pi

The OpenVX 1.3 implementation is available on GitHub. To build and install the library, follow the instructions below.

Build OpenVX 1.3 on Raspberry Pi

Git clone the project with the recursive flag to get submodules:

git clone --recursive https://github.com/KhronosGroup/OpenVX-sample-impl.git

Note: The API Documents and Conformance Test Suite are set as submodules in the sample implementation project.

Use the Build.py script to build and install OpenVX 1.3:

cd OpenVX-sample-impl/
python Build.py --os=Linux --venum --conf=Debug --conf_vision --enh_vision --conf_nn

Build and run the conformance:

export OPENVX_DIR=$(pwd)/install/Linux/x32/Debug
export VX_TEST_DATA_PATH=$(pwd)/cts/test_data/
mkdir build-cts
cd build-cts
cmake -DOPENVX_INCLUDES=$OPENVX_DIR/include -DOPENVX_LIBRARIES=$OPENVX_DIR/bin/libopenvx.so\;$OPENVX_DIR/bin/libvxu.so\;pthread\;dl\;m\;rt -DOPENVX_CONFORMANCE_VISION=ON -DOPENVX_USE_ENHANCED_VISION=ON -DOPENVX_CONFORMANCE_NEURAL_NETWORKS=ON ../cts/
cmake --build .
LD_LIBRARY_PATH=./lib ./bin/vx_test_conformance

Sample application

Use the open-source samples on GitHub to test the installation.

The post OpenVX API for Raspberry Pi appeared first on Raspberry Pi.

Volunteer your Raspberry Pi to IBM’s World Community Grid

Post Syndicated from Alex Bate original https://www.raspberrypi.org/blog/ibm-world-community-grid/

IBM’s World Community Grid is working with scientists at Scripps Research on computational experiments to help find potential COVID-19 treatments. Anyone with a Raspberry Pi and an internet connection can help.

Why is finding potential treatments for COVID-19 so important?

Scientists all over the globe are working hard to create a vaccine that could help prevent the spread of COVID-19. However, this process is likely to take many months — or possibly even years.

In the meantime, scientists are also searching for potential treatments for the symptoms of COVID-19. A project called OpenPandemics – COVID-19 is one such effort. The project is led by researchers in the Forli Lab at Scripps Research, who are enlisting the help of World Community Grid volunteers.

What is World Community Grid and how does it work? 

World Community Grid is an IBM social responsibility initiative that supports humanitarian scientific research. 

Image text reads: Accelerate research with no investment of time or money. When you become a World Community Grid volunteer, you donate your device's spare computing power to help scientists solve the world's biggest problems in health and sustainability.

As a World Community Grid volunteer, you download a secure software program to your Raspberry Pi, macOS or Windows computer, or Android device. This software program (called BOINC) is used to run World Community Grid projects, and is compatible with the Raspberry Pi OS and most other operating systems. Then, when your device is not using its full power, it automatically runs a simulated experiment in the background that will help predict the effectiveness of a particular chemical compound as a possible treatment for COVID-19. Finally, your device automatically returns the results of the completed simulation and requests the next simulation.

Over the course of the project, volunteers’ devices will run millions of simulations of small molecules interacting with portions of the virus that causes COVID-19. This is a process known as molecular docking, which is the study of how two or more molecules fit together. When a simulated chemical compound fits, or ‘docks’, with a simulation of part of the virus that causes COVID-19, that interaction may point to a potential treatment for the disease.

An image of a calendar with the text: Get results that matter. As a World Community Grid volunteer, your device does research calculations when it's idle, so just by using it as. you do every dat you can help scientists get results in months instead of decades. With your help, they can identify the most important areas to study in the lab, bringing them one step closer to discoveries that save lives and address global problems.

World Community Grid combines the results from your device along with millions of results from other volunteers all over the world and sends them to the Scripps Research team for analysis. While this process doesn’t happen overnight, it accelerates dramatically what would otherwise take many years, or might even be impossible.

OpenPandemics – COVID-19 is the first World Community Grid project to harness the power of Raspberry Pi devices, but the World Community Grid technical team is already working to make other projects available for Raspberry Pi very soon.

Getting ready for future pandemics

Scientists have learned from past outbreaks that pandemics caused by newly emerging pathogens may become more and more common. That’s why OpenPandemics – COVID-19 was designed to be rapidly deployed to fight future diseases, ideally before they reach a critical stage.

A image of a scientist using a microscope. Text reads: Your device could help search for potential treatments for COVID-19. Scientists are using World Community Grid to accelerate the search for treatments to COVIS-19. The tools and techniques the scientists develop to fight COVID-19 could be used in the future by all researchers to help more quickly find treatments for potential pandemics

To help address future pandemics, researchers need access to swift and effective tools that can be deployed very early, as soon as a threatening disease is identified. So, the researchers behind OpenPandemics – COVID-19 are creating a software infrastructure to streamline the process of finding potential treatments for other diseases. And in keeping with World Community Grid’s open data policy, they will make their findings and these tools freely available to the scientific community. 

Join a global community of science supporters

World Community Grid is thrilled to make OpenPandemics – COVID-19 available to everyone who wants to donate computing power from their Raspberry Pi. Every device can play a part in helping the search for COVID-19 treatments. Please join us!

The post Volunteer your Raspberry Pi to IBM’s World Community Grid appeared first on Raspberry Pi.

Share your keyboard and mouse between computers with Barrier

Post Syndicated from Gordon Hollingworth original https://www.raspberrypi.org/blog/share-your-keyboard-and-mouse-between-computers-with-barrier/

Declutter your desk by sharing your mouse and keyboard across multiple computers at once, including your Raspberry Pis, with Barrier. Raspberry Pi Director of Software Engineering, Gordon Hollingworth, shows you how.

Barrier walkthrough

Subscribe to our YouTube channel: http://rpf.io/ytsub Help us reach a wider audience by translating our video content: http://rpf.io/yttranslate Buy a Raspbe…

Desk clutter is a given

My desk is a bit untidy. Talking to people in our office, you’ll find that it’s mostly because I only clear it properly once a year, or leave it entirely until the next time we move office!

It’s cluttered with Raspberry Pis of random types, with little tags saying what’s wrong or right about each one, and then there’s every manner of SD card, adapter, JTAG connector, headphones, and whiteboard marker pens you can dream of filling the gaps.

But one thing that really annoys me is that I tend to have a mouse and keyboard per computer, and I’ve got at least four computers running at my desk at any one time.

Solutions to this problem have existed for a very long time, known as KVM (keyboard, video and mouse) switches; many people use these to switch (literally with a big toggle switch) between computer 1, 2, and 3 while using a single screen.

But if that’s what you want to do, the best solution is to use VNC on each of the computers so you can use a single display, keyboard, and mouse to access each of their screens and bring them all together.

And, that’s okay, but…

But that’s not quite what I want: I like having the mass-screen real-estate around me, and I like just glancing to the left to see my Raspberry Pi on its own screen.

If only there was a way to share my mouse and keyboard across multiple computers without having to flick switches or unplug USBs.

Well…

Barrier to the rescue!

In the same way one may set up multiple monitors for one computer, and move the mouse cursor seamlessly between them, Barrier allows you to share peripherals between multiple computers, allowing you to host your keyboard and mouse on one computer. It lets you simply drag your cursor from screen to screen, from device to device, as if by magic.

Download and set up Barrier

Barrier is free to use, and simple to set up. You can either follow the video tutorial shared above, or continue reading below:

Download barrier to your main computer

First, download and install Barrier from the developers’ installation page: github.com/debauchee/barrier/releases

At the end of the installation, the application will run. Select the Server option (the server is the one that has the keyboard and mouse that you want to share).

Next select Configure Server. Click on the computer screen in the top-right and drag it to where you want it to appear in relation to the server. It will default to being called ‘Unnamed’.

Next, double-click the new ‘Unnamed’ screen to set it up.

The only thing you need to do here is to set the screen name. Here I’ve changed it to ‘raspberrypi’.  Click OK here and on the Server configuration‘ dialogue. You’ll return to the main Barrier page. Click Reload.

Download Barrier to your Raspberry Pi computer

Now turn to your Raspberry Pi, open a terminal window (Ctrl-Alt-T if you didn’t know), and run:

sudo apt install barrier

Once installation is complete, Barrier should appear in the Accessories drop-down menu, which you can access via the main menu icon (the Raspberry Pi logo in the top right-hand corner). Select Barrier and, this time, choose Client.

If you leave Auto config selected, Barrier should just work, as long as the screen name is correct (you can change this by clicking Barrier and then Change settings) and matches the name you told the server.

And there you have it. You can now use your mouse and keyboard across both your computers. And, if you have enough desktop space for even more monitors, you can continue to add devices to Barrier until your room ends up looking something like this:

A man standing in front of a wall made of computer screens

If you use Barrier to clean up your workspace, make sure to share a ‘before’ and ‘after’ photo with us on Twitter.

The post Share your keyboard and mouse between computers with Barrier appeared first on Raspberry Pi.

Setting up two-factor authentication on your Raspberry Pi

Post Syndicated from Alasdair Allan original https://www.raspberrypi.org/blog/setting-up-two-factor-authentication-on-your-raspberry-pi/

Enabling two-factor authentication (2FA) to boost security for your important accounts is becoming a lot more common these days. However you might be surprised to learn that you can do the same with your Raspberry Pi. You can enable 2FA on Raspberry Pi, and afterwards you’ll be challenged for a verification code when you access it remotely via Secure Shell (SSH).

Accessing your Raspberry Pi via SSH

A lot of people use a Raspberry Pi at home as a file, or media, server. This is has become rather common with the launch of Raspberry Pi 4, which has both USB 3 and Gigabit Ethernet. However, when you’re setting up this sort of server you often want to run it “headless”; without a monitor, keyboard, or mouse. This is especially true if you intend tuck your Raspberry Pi away behind your television, or somewhere else out of the way. In any case, it means that you are going to need to enable Secure Shell (SSH) for remote access.

However, it’s also pretty common to set up your server so that you can access your files when you’re away from home, making your Raspberry Pi accessible from the Internet.

Most of us aren’t going to be out of the house much for a while yet, but if you’re taking the time right now to build a file server, you might want to think about adding some extra security. Especially if you intend to make the server accessible from the Internet, you probably want to enable two-factor authentication (2FA) using Time-based One-Time Password (TOTP).

What is two-factor authentication?

Two-factor authentication is an extra layer of protection. As well as a password, “something you know,” you’ll need another piece of information to log in. This second factor will be based either on “something you have,” like a smart phone, or on “something you are,” like biometric information.

We’re going to go ahead and set up “something you have,” and use your smart phone as the second factor to protect your Raspberry Pi.

Updating the operating system

The first thing you should do is make sure your Raspberry Pi is up to date with the latest version of Raspbian. If you’re running a relatively recent version of the operating system you can do that from the command line:

$ sudo apt-get update
$ sudo apt-get full-upgrade

If you’re pulling your Raspberry Pi out of a drawer for the first time in a while, though, you might want to go as far as to install a new copy of Raspbian using the new Raspberry Pi Imager, so you know you’re working from a good image.

Enabling Secure Shell

The Raspbian operating system has the SSH server disabled on boot. However, since we’re intending to run the board without a monitor or keyboard, we need to enable it if we want to be able to SSH into our Raspberry Pi.

The easiest way to enable SSH is from the desktop. Go to the Raspbian menu and select “Preferences > Raspberry Pi Configuration”. Next, select the “Interfaces” tab and click on the radio button to enable SSH, then hit “OK.”

You can also enable it from the command line using systemctl:

$ sudo systemctl enable ssh
$ sudo systemctl start ssh

Alternatively, you can enable SSH using raspi-config, or, if you’re installing the operating system for the first time, you can enable SSH as you burn your SD Card.

Enabling challenge-response

Next, we need to tell the SSH daemon to enable “challenge-response” passwords. Go ahead and open the SSH config file:

$ sudo nano /etc/ssh/sshd_config

Enable challenge response by changing ChallengeResponseAuthentication from the default no to yes.

Editing /etc/ssh/ssd_config.

Then restart the SSH daemon:

$ sudo systemctl restart ssh

It’s good idea to open up a terminal on your laptop and make sure you can still SSH into your Raspberry Pi at this point — although you won’t be prompted for a 2FA code quite yet. It’s sensible to check that everything still works at this stage.

Installing two-factor authentication

The first thing you need to do is download an app to your phone that will generate the TOTP. One of the most commonly used is Google Authenticator. It’s available for Android, iOS, and Blackberry, and there is even an open source version of the app available on GitHub.

Google Authenticator in the App Store.

So go ahead and install Google Authenticator, or another 2FA app like Authy, on your phone. Afterwards, install the Google Authenticator PAM module on your Raspberry Pi:

$ sudo apt install libpam-google-authenticator

Now we have 2FA installed on both our phone, and our Raspberry Pi, we’re ready to get things configured.

Configuring two-factor authentication

You should now run Google Authenticator from the command line — without using sudo — on your Raspberry Pi in order to generate a QR code:

$ google-authenticator

Afterwards you’re probably going to have to resize the Terminal window so that the QR code is rendered correctly. Unfortunately, it’s just slightly wider than the standard 80 characters across.

The QR code generated by google-authenticator. Don’t worry, this isn’t the QR code for my key; I generated one just for this post that I didn’t use.

Don’t move forward quite yet! Before you do anything else you should copy the emergency codes and put them somewhere safe.

These codes will let you access your Raspberry Pi — and turn off 2FA — if you lose your phone. Without them, you won’t be able to SSH into your Raspberry Pi if you lose or break the device you’re using to authenticate.

Next, before we continue with Google Authenticator on the Raspberry Pi, open the Google Authenticator app on your phone and tap the plus sign (+) at the top right, then tap on “Scan barcode.”

Your phone will ask you whether you want to allow the app access to your camera; you should say “Yes.” The camera view will open. Position the barcode squarely in the green box on the screen.

Scanning the QR code with the Google Authenticator app.

As soon as your phone app recognises the QR code it will add your new account, and it will start generating TOTP codes automatically.

The TOTP in Google Authenticator app.

Your phone will generate a new one-time password every thirty seconds. However, this code isn’t going to be all that useful until we finish what we were doing on your Raspberry Pi. Switch back to your terminal window and answer “Y” when asked whether Google Authenticator should update your .google_authenticator file.

Then answer “Y” to disallow multiple uses of the same authentication token, “N” to increasing the time skew window, and “Y” to rate limiting in order to protect against brute-force attacks.

You’re done here. Now all we have to do is enable 2FA.

Enabling two-factor authentication

We’re going to use Linux Pluggable Authentication Modules (PAM), which provides dynamic authentication support for applications and services, to add 2FA to SSH on Raspberry Pi.

Now we need to configure PAM to add 2FA:

$ sudo nano /etc/pam.d/sshd

Add auth required pam_google_authenticator.so to the top of the file. You can do this either above or below the line that says @include common-auth.

Editing /etc/pam.d/sshd.

As I prefer to be prompted for my verification code after entering my password, I’ve added this line after the @include line. If you want to be prompted for the code before entering your password you should add it before the @include line.

Now restart the SSH daemon:

$ sudo systemctl restart ssh

Next, open up a terminal window on your laptop and try and SSH into your Raspberry Pi.

Wrapping things up

If everything has gone to plan, when you SSH into the Raspberry Pi, you should be prompted for a TOTP after being prompted for your password.

SSH’ing into my Raspberry Pi.

You should go ahead and open Google Authenticator on your phone, and enter the six-digit code when prompted. Then you should be logged into your Raspberry Pi as normal.

You’ll now need your phone, and a TOTP, every time you ssh into, or scp to and from, your Raspberry Pi. But because of that, you’ve just given a huge boost to the security of your device.

Now you have the Google Authenticator app on your phone, you should probably start enabling 2FA for your important services and sites — like Google, Twitter, Amazon, and others — since most bigger sites, and many smaller ones, now support two-factor authentication.

The post Setting up two-factor authentication on your Raspberry Pi appeared first on Raspberry Pi.

How to work from home with Raspberry Pi | The Magpi 93

Post Syndicated from Ashley Whittaker original https://www.raspberrypi.org/blog/how-to-work-from-home-with-raspberry-pi-the-magpi-93/

If you find yourself working or learning, or simply socialising from home, Raspberry Pi can help with everything from collaborative productivity to video conferencing. Read more in issue #92 of The MagPi, out now.

01 Install the camera

If you’re using a USB webcam, you can simply insert it into a USB port on Raspberry Pi. If you’re using a Raspberry Pi Camera Module, you’ll need to unpack it, then find the ‘CAMERA’ port on the top of Raspberry Pi – it’s just between the second micro-HDMI port and the 3.5mm AV port. Pinch the shorter sides of the port’s tab with your nails and pull it gently upwards. With Raspberry Pi positioned so the HDMI ports are at the bottom, insert one end of the camera’s ribbon cable into the port so the shiny metal contacts are facing the HDMI port. Hold the cable in place, and gently push the tab back home again.

If the Camera Module doesn’t have the ribbon cable connected, repeat the process for the connector on its underside, making sure the contacts are facing downwards towards the module. Finally, remove the blue plastic film from the camera lens.

02 Enable Camera Module access

Before you can use your Raspberry Pi Camera Module, you need to enable it in Raspbian. If you’re using a USB webcam, you can skip this step. Otherwise, click on the raspberry menu icon in Raspbian, choose Preferences, then click on Raspberry Pi Configuration.

When the tool loads, click on the Interfaces tab, then click on the ‘Enabled’ radio button next to Camera. Click OK, and let Raspberry Pi reboot to load your new settings. If you forget this step, Raspberry Pi won’t be able to communicate with the Camera Module.

03 Set up your microphone

If you’re using a USB webcam, it may come with a microphone built-in; otherwise, you’ll need to connect a USB headset, a USB microphone and separate speakers, or a USB sound card with analogue microphone and speakers to Raspberry Pi. Plug the webcam into one of Raspberry Pi’s USB 2.0 ports, furthest away from the Ethernet connector and marked with black plastic inners.

Right-click on the speaker icon at the top-right of the Raspbian desktop and choose Audio Inputs. Find your microphone or headset in the list, then click it to set it as the default input. If you’re using your TV or monitor’s speakers, you’re done; if you’re using a headset or separate speakers, right-click on the speaker icon and choose your device from the Audio Outputs menu as well.

04 Set access permissions

Click on the Internet icon next to the raspberry menu to load the Chromium web browser. Click in the address box and type hangouts.google.com. When the page loads, click ‘Sign In’ and enter your Google account details; if you don’t already have a Google account, you can sign up for one free of charge.

When you’ve signed in, click Video Call. You’ll be prompted to allow Google Hangouts to access both your microphone and your camera. Click Allow on the prompt that appears. If you Deny access, nobody in the video chat will be able to see or hear you!

05 Invite friends or join a chat

You can invite friends to your video chat by writing their email address in the Invite People box, or copying the link and sending it via another messaging service. They don’t need their own Raspberry Pi to participate – you can use Google Hangouts from a laptop, desktop, smartphone, or tablet. If someone has sent you a link to their video chat, open the message on Raspberry Pi and simply click the link to join automatically.

You can click the microphone or video icons at the bottom of the window to temporarily disable the microphone or camera; click the red handset icon to leave the call. You can click the three dots at the top-right to access more features, including switching the chat to full-screen view and sharing your screen – which will allow guests to see what you’re doing on Raspberry Pi, including any applications or documents you have open.

06 Adjust microphone volume

If your microphone is too quiet, you’ll need to adjust the volume. Click the Terminal icon at the upper-left of the screen, then type alsamixer followed by the ENTER key. This loads an audio mixing tool; when it opens, press F4 to switch to the Capture tab and use the up-arrow and down-arrow keys on the keyboard to increase or decrease the volume. Try small adjustments at first; setting the capture volume too high can cause the audio to ‘clip’, making you harder to hear. When finished, press CTRL+C to exit AlsaMixer, then click the X at the top-right of the Terminal to close it.

Adjust your audio volume settings with the AlsaMixer tool

Work online with your team

Just because you’re not shoulder-to-shoulder with colleagues doesn’t mean you can’t collaborate, thanks to these online tools.

Google Docs

Google Docs is a suite of online productivity tools linked to the Google Drive cloud storage platform, all accessible directly from your browser. Open the browser and go to drive.google.com, then sign in with your Google account – or sign up for a new account if you don’t already have one – for 15GB of free storage plus access to the word processor Google Docs, spreadsheet Google Sheets, presentation tool Google Slides, and more. Connect with colleagues and friends to share files or entire folders, and collaborate within documents with simultaneous multi-user editing, comments, and change suggestions.

Slack

Designed for business, Slack is a text-based instant messaging tool with support for file transfer, rich text, images, video, and more. Slack allows for easy collaboration in Teams, which are then split into multiple channels or rooms – some for casual conversation, others for more focused discussion. If your colleagues or friends already have a Slack team set up, ask them to send you an invite; if not, you can head to app.slack.com and set one up yourself for free.

Discord

Built more for casual use, Discord offers live chat functionality. While the dedicated Discord app includes voice chat support, this is not yet supported on Raspberry Pi – but you can still use text chat by opening the browser, going to discord.com, and choosing the ‘Open Discord in your browser’ option. Choose a username, read and agree to the terms of service, then enter an email address and password to set up your own free Discord server. Alternatively, if you know someone on Discord already, ask them to send you an invitation to access their server.

Firefox Send

If you need to send a document, image, or any other type of file to someone who isn’t on Google Drive, you can use Firefox Send – even if you’re not using the Firefox browser. All files transferred via Firefox Send are encrypted, and can be protected with an optional password, and are automatically deleted after a set number of downloads or length of time. Simply open the browser and go to send.firefox.com; you can send files up to 1GB without an account, or sign up for a free Firefox account to increase the limit to 2.5GB.

GitHub

For programmers, GitHub is a lifesaver. Based around the Git version control system, GitHub lets teams work on a project regardless of distance using repositories of source code and supporting files. Each programmer can have a local copy of the program files, work on them independently, then submit the changes for inclusion in the master copy – complete with the ability to handle conflicting changes. Better still, GitHub offers additional collaboration tools including issue tracking. Open the browser and go to github.com to sign up, or sign in if you have an existing account, and follow the getting started guide on the site.

Read The MagPi for free!

Find more fantastic projects, tutorials, and reviews in The MagPi #93, out now! You can get The MagPi #92 online at our store, or in print from all good newsagents and supermarkets. You can also access The MagPi magazine via our Android and iOS apps.

Don’t forget our super subscription offers, which include a free gift of a Raspberry Pi Zero W when you subscribe for twelve months.

And, as with all our Raspberry Pi Press publications, you can download the free PDF from our website.

The post How to work from home with Raspberry Pi | The Magpi 93 appeared first on Raspberry Pi.

An open source camera stack for Raspberry Pi using libcamera

Post Syndicated from David Plowman original https://www.raspberrypi.org/blog/an-open-source-camera-stack-for-raspberry-pi-using-libcamera/

Since we released the first Raspberry Pi camera module back in 2013, users have been clamouring for better access to the internals of the camera system, and even to be able to attach camera sensors of their own to the Raspberry Pi board. Today we’re releasing our first version of a new open source camera stack which makes these wishes a reality.

(Note: in what follows, you may wish to refer to the glossary at the end of this post.)

We’ve had the building blocks for connecting other sensors and providing lower-level access to the image processing for a while, but Linux has been missing a convenient way for applications to take advantage of this. In late 2018 a group of Linux developers started a project called libcamera to address that. We’ve been working with them since then, and we’re pleased now to announce a camera stack that operates within this new framework.

Here’s how our work fits into the libcamera project.

We’ve supplied a Pipeline Handler that glues together our drivers and control algorithms, and presents them to libcamera with the API it expects.

Here’s a little more on what this has entailed.

V4L2 drivers

V4L2 (Video for Linux 2) is the Linux kernel driver framework for devices that manipulate images and video. It provides a standardised mechanism for passing video buffers to, and/or receiving them from, different hardware devices. Whilst it has proved somewhat awkward as a means of driving entire complex camera systems, it can nonetheless provide the basis of the hardware drivers that libcamera needs to use.

Consequently, we’ve upgraded both the version 1 (Omnivision OV5647) and version 2 (Sony IMX219) camera drivers so that they feature a variety of modes and resolutions, operating in the standard V4L2 manner. Support for the new Raspberry Pi High Quality Camera (using the Sony IMX477) will be following shortly. The Broadcom Unicam driver – also V4L2‑based – has been enhanced too, signalling the start of each camera frame to the camera stack.

Finally, dumping raw camera frames (in Bayer format) into memory is of limited value, so the V4L2 Broadcom ISP driver provides all the controls needed to turn raw images into beautiful pictures!

Configuration and control algorithms

Of course, being able to configure Broadcom’s ISP doesn’t help you to know what parameters to supply. For this reason, Raspberry Pi has developed from scratch its own suite of ISP control algorithms (sometimes referred to generically as 3A Algorithms), and these are made available to our users as well. Some of the most well known control algorithms include:

  • AEC/AGC (Auto Exposure Control/Auto Gain Control): this monitors image statistics into order to drive the camera exposure to an appropriate level.
  • AWB (Auto White Balance): this corrects for the ambient light that is illuminating a scene, and makes objects that appear grey to our eyes come out actually grey in the final image.

But there are many others too, such as ALSC (Auto Lens Shading Correction, which corrects vignetting and colour variation across an image), and control for noise, sharpness, contrast, and all other aspects of image processing. Here’s how they work together.

The control algorithms all receive statistics information from the ISP, and cooperate in filling in metadata for each image passing through the pipeline. At the end, the metadata is used to update control parameters in both the image sensor and the ISP.

Previously these functions were proprietary and closed source, and ran on the Broadcom GPU. Now, the GPU just shovels pixels through the ISP hardware block and notifies us when it’s done; practically all the configuration is computed and supplied from open source Raspberry Pi code on the ARM processor. A shim layer still exists on the GPU, and turns Raspberry Pi’s own image processing configuration into the proprietary functions of the Broadcom SoC.

To help you configure Raspberry Pi’s control algorithms correctly for a new camera, we include a Camera Tuning Tool. Or if you’d rather do your own thing, it’s easy to modify the supplied algorithms, or indeed to replace them entirely with your own.

Why libcamera?

Whilst ISP vendors are in some cases contributing open source V4L2 drivers, the reality is that all ISPs are very different. Advertising these differences through kernel APIs is fine – but it creates an almighty headache for anyone trying to write a portable camera application. Fortunately, this is exactly the problem that libcamera solves.

We provide all the pieces for Raspberry Pi-based libcamera systems to work simply “out of the box”. libcamera remains a work in progress, but we look forward to continuing to help this effort, and to contributing an open and accessible development platform that is available to everyone.

Summing it all up

So far as we know, there are no similar camera systems where large parts, including at least the control (3A) algorithms and possibly driver code, are not closed and proprietary. Indeed, for anyone wishing to customise a camera system – perhaps with their own choice of sensor – or to develop their own algorithms, there would seem to be very few options – unless perhaps you happen to be an extremely large corporation.

In this respect, the new Raspberry Pi Open Source Camera System is providing something distinctly novel. For some users and applications, we expect its accessible and non-secretive nature may even prove quite game-changing.

What about existing camera applications?

The new open source camera system does not replace any existing camera functionality, and for the foreseeable future the two will continue to co-exist. In due course we expect to provide additional libcamera-based versions of raspistill, raspivid and PiCamera – so stay tuned!

Where next?

If you want to learn more about the libcamera project, please visit https://libcamera.org.

To try libcamera for yourself with a Raspberry Pi, please follow the instructions in our online documentation, where you’ll also find the full Raspberry Pi Camera Algorithm and Tuning Guide.

If you’d like to know more, and can’t find an answer in our documentation, please go to the Camera Board forum. We’ll be sure to keep our eyes open there to pick up any of your questions.

Acknowledgements

Thanks to Naushir Patuck and Dave Stevenson for doing all the really tricky bits (lots of V4L2-wrangling).

Thanks also to the libcamera team (Laurent Pinchart, Kieran Bingham, Jacopo Mondi and Niklas Söderlund) for all their help in making this project possible.

 

Glossary

3A, 3A Algorithms: refers to AEC/AGC (Auto Exposure Control/Auto Gain Control), AWB (Auto White Balance) and AF (Auto Focus) algorithms, but may implicitly cover other ISP control algorithms. Note that Raspberry Pi does not implement AF (Auto Focus), as none of our supported camera modules requires it
AEC: Auto Exposure Control
AF: Auto Focus
AGC: Auto Gain Control
ALSC: Auto Lens Shading Correction, which corrects vignetting and colour variations across an image. These are normally caused by the type of lens being used and can vary in different lighting conditions
AWB: Auto White Balance
Bayer: an image format where each pixel has only one colour component (one of R, G or B), creating a sort of “colour mosaic”. All the missing colour values must subsequently be interpolated. This is a raw image format meaning that no noise, sharpness, gamma, or any other processing has yet been applied to the image
CSI-2: Camera Serial Interface (version) 2. This is the interface format between a camera sensor and Raspberry Pi
GPU: Graphics Processing Unit. But in this case it refers specifically to the multimedia coprocessor on the Broadcom SoC. This multimedia processor is proprietary and closed source, and cannot directly be programmed by Raspberry Pi users
ISP: Image Signal Processor. A hardware block that turns raw (Bayer) camera images into full colour images (either RGB or YUV)
Raw: see Bayer
SoC: System on Chip. The Broadcom processor at the heart of all Raspberry Pis
Unicam: the CSI-2 receiver on the Broadcom SoC on the Raspberry Pi. Unicam receives pixels being streamed out by the image sensor
V4L2: Video for Linux 2. The Linux kernel driver framework for devices that process video images. This includes image sensors, CSI-2 receivers, and ISPs

The post An open source camera stack for Raspberry Pi using libcamera appeared first on Raspberry Pi.

New book: The Official Raspberry Pi Camera Guide

Post Syndicated from Alex Bate original https://www.raspberrypi.org/blog/new-book-the-official-raspberry-pi-camera-guide/

To coincide with yesterday’s launch of the Raspberry Pi High Quality Camera, Raspberry Pi Press has created a new Official Camera Guide to help you get started and inspire your future projects.

The Raspberry Pi High Quality Camera

Connecting a High Quality Camera turns your Raspberry Pi into a powerful digital camera. This 132-page book tells you everything you need to know to set up the camera, attach a lens, and start capturing high-resolution photos and video footage.

Make those photos snazzy

The book tells you everything you need to know in order to use the camera by issuing commands in a terminal window or via SSH. It also demonstrates how to control the camera with Python using the excellent picamera library.

You’ll discover the many image modes and effects available – our favourite is ‘posterise’.

Build some amazing camera-based projects

Once you’ve got the basics down, you can start using your camera for a variety of exciting Raspberry Pi projects showcased across the book’s 17 packed chapters. Want to make a camera trap to monitor the wildlife in your garden? Build a smart door with a video doorbell? Try out high-speed and time-lapse photography? Or even find out which car is parked in your driveway using automatic number-plate recognition? The book has all this covered, and a whole lot more.

Don’t have a High Quality Camera yet? No problem. All the commands in the book are exactly the same for the standard Raspberry Pi Camera Module, so you can also use this model with the help of our Official Camera Guide.

Snap it up!

The Official Raspberry Pi Camera Guide is available now from the Raspberry Pi Press online store for £10. And, as always, we have also released the book as a free PDF. But the physical book feels so good to hold and looks so handsome on your bookshelf, we don’t think you’ll regret getting your hands on the print edition.

Whichever format you choose, have fun shooting amazing photos and videos with the new High Quality Camera. And do share what you capture with us on social media using #ShotOnRaspberryPi.

The post New book: The Official Raspberry Pi Camera Guide appeared first on Raspberry Pi.

New product: Raspberry Pi High Quality Camera on sale now at $50

Post Syndicated from Simon Martin original https://www.raspberrypi.org/blog/new-product-raspberry-pi-high-quality-camera-on-sale-now-at-50/

We’re pleased to announce a new member of the Raspberry Pi camera family: the 12.3-megapixel High Quality Camera, available today for just $50, alongside a range of interchangeable lenses starting at $25.

NEW Raspberry Pi High Quality Camera

Subscribe to our YouTube channel: http://rpf.io/ytsub Help us reach a wider audience by translating our video content: http://rpf.io/yttranslate Buy a Raspbe…

It’s really rather good, as you can see from this shot of Cambridge’s finest bit of perpendicular architecture.

At 69 years, King’s College Chapel took only slightly longer to finish than the High Quality Camera.

And this similarly pleasing bit of chip architecture.

Ready for your closeup.

Raspberry Pi and the camera community

There has always been a big overlap between Raspberry Pi hackers and camera hackers. Even back in 2012, people (okay, substantially Dave Hunt) were finding interesting ways to squeeze more functionality out of DSLR cameras using their Raspberry Pi computers.

Dave’s water droplet photography. Still, beautiful.

The OG Raspberry Pi camera module

In 2013, we launched our first camera board, built around the OmniVision OV5647 5‑megapixel sensor, followed rapidly by the original Pi NoIR board, with infrared sensitivity and a little magic square of blue plastic. Before long, people were attaching them to telescopes and using them to monitor plant health from drones (using the aforementioned little square of plastic).

TJ EMSLEY Moon Photography

We like the Moon.

Sadly, OV5647 went end-of-life in 2015, and the 5-megapixel camera has the distinction of being one of only three products (along with the original Raspberry Pi 1 and the official WiFi dongle) that we’ve ever discontinued. Its replacement, built around the 8-megapixel Sony IMX219 sensor, launched in April 2016; it has found a home in all sorts of cool projects, from line-followers to cucumber sorters, ever since. Going through our sales figures while writing this post, we were amazed to discover we’ve sold over 1.7 million of these to date.

The limitations of fixed-focus

Versatile though they are, there are limitations to mobile phone-type fixed-focus modules. The sensors themselves are relatively small, which translates into a lower signal-to-noise ratio and poorer low-light performance; and of course there is no option to replace the lens assembly with a more expensive one, or one with different optical properties. These are the shortcomings that the High Quality Camera is designed to address.

Photograph of a Raspberry Pi 4 captured by the Raspberry Pi Camera Module v2
Photograph of a Raspberry Pi 4 captured by the Raspberry Pi High Quality Camera

Raspberry Pi High Quality Camera

Raspberry Pi High Quality Camera, without a lens attached

Features include:

  • 12.3 megapixel Sony IMX477 sensor
  • 1.55μm × 1.55μm pixel size – double the pixel area of IMX219
  • Back-illuminated sensor architecture for improved sensitivity
  • Support for off-the-shelf C- and CS-mount lenses
  • Integrated back-focus adjustment ring and tripod mount

We expect that over time people will use quite a wide variety of lenses, but for starters our Approved Resellers will be offering a couple of options: a 6 mm CS‑mount lens at $25, and a very shiny 16 mm C-mount lens priced at $50.

Our launch-day lens selection.

Read all about it

Also out today is our new Official Raspberry Pi Camera Guide, covering both the familiar Raspberry Pi Camera Module and the new Raspberry Pi High Quality Camera.

We’ll never not be in love with Jack’s amazing design work.

Our new guide, published by Raspberry Pi Press, walks you through setting up and using your camera with your Raspberry Pi computer. You’ll also learn how to use filters and effects to enhance your photos and videos, and how to set up creative projects such as stop-motion animation stations, wildlife cameras, smart doorbells, and much more.

Aardman ain’t got nothing on you.

You can purchase the book in print today from the Raspberry Pi Press store for £10, or download the PDF for free from The MagPi magazine website.

Credits

As with every product we build, the High Quality Camera has taught us interesting new things, in this case about producing precision-machined aluminium components at scale (and to think we thought injection moulding was hard!). Getting this right has been something of a labour of love for me over the past three years, designing the hardware and getting it to production. Naush Patuck tuned the VideoCore IV ISP for this sensor; David Plowman helped with lens evaluation; Phil King produced the book; Austin Su provided manufacturing support.

We’d like to acknowledge Phil Holden at Sony in San Jose, the manufacturing team at Sony UK Tec in Pencoed for their camera test and assembly expertise, and Shenzhen O-HN Optoelectronic for solving our precision engineering challenges.

FAQS

Which Raspberry Pi models support the High Quality Camera?

The High Quality Camera is compatible with almost all Raspberry Pi models, from the original Raspberry Pi 1 Model B onward. Some very early Raspberry Pi Zero boards from the start of 2016 lack a camera connector, and other Zero users will need the same adapter FPC that is used with Camera Module v2.

What about Camera Module v2?

The regular and infrared versions of Camera Module v2 will still be available. The High Quality Camera does not supersede it. Instead, it provides a different tradeoff between price, performance, and size.

What lenses can I use with the High Quality Camera?

You can use C- and CS-mount lenses out of the box (C-mount lenses use the included C-CS adapter). Third-party adapters are available from a wide variety of lens standards to CS-mount, so it is possible to connect any lens that meets the back‑focus requirements.

We’re looking forward to seeing the oldest and/or weirdest lenses anyone can get working, but here’s one for starters, courtesy of Fiacre.

Do not try this at home. Or do: fine either way.

The post New product: Raspberry Pi High Quality Camera on sale now at $50 appeared first on Raspberry Pi.

Printing at home from your Raspberry Pi

Post Syndicated from Alasdair Allan original https://www.raspberrypi.org/blog/printing-at-home-from-your-raspberry-pi/

Yesterday I wrote about working from home with your Raspberry Pi, and talked about things like how to connect to your company VPN, and how to get video conferencing up and working. However, one thing I didn’t talk about – and that many of you have asked for some guidance on – was printing.

To get printing up and working on your Raspberry Pi the first thing you need to do is install CUPS. CUPS is an open source printing system developed by Apple that uses the Internet Printing Protocol (IPP) to support printing to both local and network printers.

Installing CUPS

Go ahead and open a terminal window, and install CUPS.

$ sudo apt-get install cups

CUPS has a lot of dependencies, so depending on your broadband connection installation, it could take a while. If you have any left in the house, now might be a good time for a cup of coffee ☕.

After installation you’ll need to give the pi user administrative rights on CUPS. To do this, go back to your console and type

$ sudo usermod -a -G lpadmin pi

to make the pi user part of the lpadmin group.

Adding a printer

Now open up your browser and navigate to https://localhost:631 . You’ll receive a security warning from your browser. Hit the ‘Advanced’ button and then ‘Proceed to localhost (unsafe)’.

Accepting the locally generated certificate

You’ll be presented with the CUPS interface. Click on ‘Administration’ in the top bar, and a drop-down will appear. Authorise yourself to CUPS as the pi user, which we’d added to the administrator group earlier.

Authorising yourself with CUPS as an administrator

After you authorise yourself, click on the ‘Add Printer’ button. CUPS will then look for locally connected (via USB) printers as well as any networked printers it can see on your home network.

For a lot of printers you’ll be presented with a number of possible options, as most modern printers offer a number of ways to connect. So depending on which printer you have, you might need to go through the process of adding a printer a couple of times to figure out the best method to connect.

Adding a printer in CUPS

I have a Brother HL-3140CW, an older model colour laser printer. While Brother offers Linux drivers, they are compiled for the x86 rather than ARM architecture, and the open source ‘brlaser’ driver doesn’t support my model. However, CUPS does list a ‘driverless’ option for communicating without a native printer driver using the Internet Printing Protocol (IPP).

Selecting a driver, I chose “IPP Everywhere”

Picking this option, I was presented with a list of drivers for the printer. I picked IPP Everywhere from the list, and hit the ‘Add Printer’ button.

Successfully added the printer

After a few seconds CUPS should present you with the ‘Printers’ tab, which should show you your connected printer. If everything is okay it should show that the printer is ‘Accepting Jobs’.

Testing the printer

Now we have our printer set up we need to test it. Go ahead and open LibreOffice Writer from the start menu, and enter some test text.

Writing a test document

Then click on ‘File > Print’ in the LibreOffice Writer menu.

Printing our test document from LibreOffice Writer

If everything has gone smoothly your printer should start making appropriate printing noises and should print your test document.

Our test documents

I actually went ahead and printed two test documents just to be sure colour printing was working okay, and happily it was working just fine!

Wrapping up

The exact process you’re going to go through to get your printer working will depend heavily on which printer you own. The trickiest bit is always going to be drivers. Thankfully, these days things are a lot easier than they used to be, as most printers – especially networked printers that live on your wireless network – offer standard ways to print and you don’t necessarily have to rely on a native (manufacturer-provided) driver any more.

The post Printing at home from your Raspberry Pi appeared first on Raspberry Pi.

Ashley’s top five projects for Raspberry Pi first-timers

Post Syndicated from Ashley Whittaker original https://www.raspberrypi.org/blog/ashleys-top-five-projects-for-raspberry-pi-first-timers/

It is time. Time to go to that little stack of gifts from well-wishers who have badged you as “techie” or noted that you “play computer games”. Armed with this information, they decided you’d like to receive one of our small and perfectly formed Raspberry Pis. You were thrilled. You could actually make a thing.

Except you haven’t. You had to go to that job thingy, and talk to that partner thingy, and wash and feed those children thingies. Don’t worry, we’re not offended. We know that embarking on your first coding project is daunting and that the community has taken off like a rocket so there are eight bajillion ideas floating around. Good job we’re here to help, then, isn’t?

First-timer project 01

Some of us have found ourselves spending more time with our online communities recently. Those whose digital family of choice is to be found on Reddit should see an uptick in their personal ‘Karma’ if they’re spending more time digging into “the front page of the internet”. If you’d like to see a real-world indicator of the fruits of your commenting/sharing/Let-Me-Google-That-For-You labour, a super-easy Raspberry Pi first-timer project is building a Karma counter, like this one we found on Reddit.

Now, Squiddles1227 is one of those flash 3D printer-owning types, but you could copy the premise and build your own crafty Karma-themed housing around your counter.

On a similar note (and featuring a comprehensive ‘How To’), GiovanniBauer on instructables.com used his Raspberry Pi to create an Instagram follower counter. Developed on Raspbian with Node.js, this project walk-through should get you started on whichever social media counter project you’d like to have a bash at.

First-timer project 02

We know this is a real-life Raspberry Pi first-timer project because the Reddit post title says so. Ninjalionman1 made an e-ink calendar using a Raspberry Pi Zero so they can see their daily appointments, weather report, and useful updates.

We mined the original Reddit thread to find you the comment linking to all the info you need about hardware and setup. Like I said, good job we’re here.

First-timer project 03

Raspberry Pi 3 and 4, as well as Raspberry Pi Zero W, come with built-in Bluetooth connectivity. This means you can build something to let your lockdown-weary self take your emotional-health-preserving music/podcasts/traditional chant soundtrack with you as you migrate around your living space. “Mornings in the lounge… mid-afternoons at the kitchen table…” – we feel you.

Circuitdigest.com posted this comprehensive walk-through to show you how a Raspberry Pi can convert an ordinary speaker with a 3.5mm jack into a wireless Bluetooth speaker.

First-timer project 04

PCWorld.com shared 10 Raspberry Pi projects they bet anyone can do, and we really like the look of this one. It shows you how to give a “dumb” TV extra smarts, like web browsing, which could be especially useful if screen availability is limited in a multi-user household.

The PCWorld article recommends using a Raspberry Pi 2, 3 or 4, and points out that this is a much cheaper option than things like Chromebits and Compute Sticks.

First-timer project 05

Lastly, electromaker.io have hidden the coding education vegetables in the Minecraft tomato sauce using Raspberry Pi. The third post down on this thread features a video explaining how you can hack your kids’ favourite game to get them learning to code.

The video blurb also helpfully points out that Minecraft comes pre-installed on Raspbian, making it “one of the greatest Pi projects for kids.”

If you’re not quite ready to jump in and try any of the above, try working your way through these really simple steps to set up your Raspberry Pi and see what it can do. Then come back here and try one of these first-timer projects, share the results of your efforts, tag us, and receive a virtual round of applause!

The post Ashley’s top five projects for Raspberry Pi first-timers appeared first on Raspberry Pi.

Don’t forget about Steam Link on Raspberry Pi

Post Syndicated from Alex Bate original https://www.raspberrypi.org/blog/dont-forget-about-steam-link-on-raspberry-pi/

Connect your gaming PC to your TV with ease, thanks to Steam Link and Raspberry Pi.

A Steam Link to the past

Back in 2018, we asked Simon, our Asset Management Assistant Keeper of the Swag, Organiser of the Stuff, Lord Commander of the Things to give Steam Link on Raspberry Pi a try for us, as he likes that sort of thing and was probably going to do it anyway.

Valve’s Steam Link, in case you don’t know, allows users of the gaming distribution platform Steam to stream video games from their PC to a display of their choice via their home network, with no need for cumbersome wires and whatnot.

Originally produced as a stand-alone box in 2018, Valve released this tool as a free download to all Raspberry Pi users, making it accessible via a single line of code. Nice!

The result of Simon’s experiment was positive: he reported that setting up Steam Link was easy, and the final product was a simple and affordable means of playing PC games on his TV, away from his PC in another room.

And now…

Well, it’s 2020 and since many of us are staying home lately, so we figured it would be nice to remind you all that this streaming service is still available.

To set up Steam Link on your Raspberry Pi, simply enter the following into a terminal window:

sudo apt update
sudo apt install steamlink

The post Don’t forget about Steam Link on Raspberry Pi appeared first on Raspberry Pi.

Build a physical game controller for Infinite Bunner

Post Syndicated from Andrew Gregory original https://www.raspberrypi.org/blog/build-a-physical-game-controller-for-infinite-bunner/

In HackSpace magazine issue 28 we had a look at how to create an ultrasonic controller for a version of Pong called Boing!. This month, we’re going to take a step further forward through video game history and look at the game Frogger. In this classic game, you control a frog as it makes its way across logs, roads, and train tracks, avoiding falling in the water or getting hit.

Infinite Bunner

The tribute to Frogger in the new Code the Classics Volume 1 book is called Infinite Bunner, and works in much the same way, except you control a bunny.

Jump along the logs, dodge the traffic, avoid the trains, and keep your bunny alive for as long as possible

All this hopping got us thinking about a controller. Our initial idea was that since the animals jump, so should the controller. An accelerometer can detect freefall, so it shouldn’t be too hard to convert that into button presses. However, it turns out that computer-controlled frogs and rabbits can jump much, much faster than humans can, and we really struggled to get a working game mechanic, so we compromised a little and worked with ‘flicks’.

The flick controller

The basic idea is that you tilt the controller left or right to move left or right, but you have to flick it up to register a jump (simply holding it upright won’t work).

We’ve used a Circuit Playground Bluefruit as our hardware, but it would work equally well with a Circuit Playground Express. There are two key parts to the software. The first is reading in accelerometer values and use these to know what orientation the board is in, and the second is the board mimicing a USB keyboard and sending keystrokes to any software running on it.

Playing Infinite Bunner

The first step is to get Infinite Bunner working on your machine.

Get your copy of Code the Classics today

You can download the code for all the Code the Classics Volume 1 games here. Click on Clone or Download > Download ZIP. Unzip the download somewhere.

You’ll need Python 3 with Pygame Zero installed. The process for this differs a little between different computers, but there’s a good overview of all the different options on page 186 of Code the Classics.

Subscribe to HackSpace magazine for twelve months and you get a Circuit Playground Express for free! Then you can make your very own Infinite Bunner controller

Once everything’s set up, open a terminal and navigate to the directory you unzipped the code in. Then, inside that, you should find a folder called bunner-master and move into that. You can then run:

python3 bunner.py

Have a few goes playing the game, and you’ll find that you need the left, right, and up arrow keys to play (there is also the down arrow, but we’ve ignored this since we’ve never actually used it in gameplay – if you’re a Frogger/Bunner aficionado, you may wish to implement this as well).

Reading the accelerometer is as easy as importing the appropriate module and running one line:

from adafruit_circuitplayground import cpx, y, z = cp.acceleration

Sending key presses is similarly easy. You can set up a keyboard with the following:

from adafruit_hid.keyboard import Keyboard
from adafruit_hid.keyboard_layout_us import KeyboardLayoutUS
from adafruit_hid.keycode import Keycode

keyboard = Keyboard(usb_hid.devices)

Then send key presses with code such as this:

time.keyboard.press(Keycode.LEFT_ARROW) time.sleep(0.1)
keyboard.release_all()

The only thing left is to slot in our mechanics. The X-axis on the accelerometer can determine if the controller is tilted left or right. The output is between 10 (all the way left) and -10 (all the way right). We chose to threshold it at 7 and -7 to require the user to tilt it most of the way. There’s a little bit of fuzz in the readings, especially as the user flicks the controller up, so having a high threshold helps avoid erroneous readings.

The Y-axis is for jumping. In this case, we require a ‘flap’ where the user first lifts it up (over a threshold of 5), then back down again.

The full code for our controller is:

import time
from adafruit_circuitplayground import cp
import usb_hid
from adafruit_hid.keyboard import Keyboard
from adafruit_hid.keyboard_layout_us import KeyboardLayoutUS
from adafruit_hid.keycode import Keycode

keyboard = Keyboard(usb_hid.devices)

jumping = 0
up=False
while True:
    x, y, z = cp.acceleration
    if abs(y) > 5:
        up=True
    if y < 5 and up:
        keyboard.press(Keycode.UP_ARROW)
        time.sleep(0.3)
        keyboard.release_all()
        up=False
    if x < -7 :
        keyboard.press(Keycode.LEFT_ARROW)
        time.sleep(0.1)
        keyboard.release_all()
    if x < 7 : keyboard.press(Keycode.RIGHT_ARROW)
        time.sleep(0.1)
        keyboard.release_all()
        time.sleep(0.1)
    if jumping > 0:
        jumping=jumping-1

It doesn’t take much CircuitPython to convert a microcontroller into a games controller

The final challenge we had was that there’s a bit of wobble when moving the controller around – especially when trying to jump repeatedly and quickly. After fiddling with thresholds for a while, we found that there’s a much simpler solution: increase the weight of the controller. The easiest way to do this is to place it inside a book. If you’ve ever held a copy of Code the Classics, you’ll know that it’s a fairly weighty tome. Just place the board inside and close the book around it, and all the jitter disappears.

That’s all there is to the controller. You can use it to play the game, just as you would any joypad. Start the game as usual, then start flapping the book around to get hopping.

HackSpace magazine is out now

The latest issue of HackSpace magazine is out today and can be purchased from the Raspberry Pi Press online store. You can also download a copy if you want to see what all the fuss is about.


Code the Classics is available from Raspberry Pi Press as well, and comes with free UK shipping. And here’s a lovely video about Code the Classics artist Dan Malone and the gorgeous artwork he created for the book:

Code the Classics: Artist Dan Malone

No Description

The post Build a physical game controller for Infinite Bunner appeared first on Raspberry Pi.

Wireframe’s deep(ish) dive into the glorious double jump

Post Syndicated from Alex Bate original https://www.raspberrypi.org/blog/wireframes-deepish-dive-into-the-glorious-double-jump/

Yoshi aside, we can’t think of anyone who isn’t a fan of the double jump. In their latest video, the Wireframe magazine team take a deep(ish) dive into one of video gaming’s most iconic moves.

What is the Double Jump | Wireframe Deep Dive

The humble jump got a kick in 1984 with the introduction of the double jump, a physicist’s worst nightmare and one of video gaming’s most iconic moves. Subsc…

Also, HDR!

Are you looking to upgrade your computer monitor? Last week, Custom PC magazine, a publication of Raspberry Pi Press, released their latest video discussing HDR monitors. Are you ready to upgrade, and more importantly, should you?

What is an HDR monitor? High dynamic range explained | Custom PC magazine

High dynamic range (HDR) monitors are all the rage, but what exactly is HDR and which monitors produce the best image quality? Check out our full HDR guide: …

We produce videos for all our Raspberry Pi Press publications, including magazines such as The MagPi and HackSpace magazine, as well as our book releases, such as Code the Classics and Build Your Own First-Person Shooter in Unity.

Subscribe to the Raspberry Pi Press YouTube channel today and click on the bell button to ensure you’re notified of all new releases. And, for our complete publication library, visit the Raspberry Pi Press online store.

The post Wireframe’s deep(ish) dive into the glorious double jump appeared first on Raspberry Pi.

How to use a button with a Raspberry Pi

Post Syndicated from Alex Bate original https://www.raspberrypi.org/blog/how-to-use-a-button-with-a-raspberry-pi/

Here’s our latest How to use video, showing you how to connect a button to your Raspberry Pi.

HOW TO USE a BUTTON with Raspberry Pi

Learn how to use a tactile button with your Raspberry Pi. They’re a great addition to any digital making project! Subscribe to our YouTube channel: http://rp…

Connect a button to Raspberry Pi

Attaching a button to your Raspberry Pi is a great way of introducing digital making into your coding experience. Use it to play music, turn lights on and off, or even shut down your device.

Follow our other How to use videos to learn how to use a servo motor, LED, and Raspberry Pi camera module with your Raspberry Pi. Try linking them together to build something grander, such as a digital camera, a robot, or a music box.

How to use Raspberry Pi

You’ll find a full list of our current How to use videos here – be sure to subscribe to our channel for more content as we release it.

The post How to use a button with a Raspberry Pi appeared first on Raspberry Pi.

Introducing Raspberry Pi Imager, our new imaging utility

Post Syndicated from Gordon Hollingworth original https://www.raspberrypi.org/blog/raspberry-pi-imager-imaging-utility/

We’ve made a simpler way to image your microSD card with Raspbian, the official Raspberry Pi operating system, and other operating systems. Introducing our new imaging utility, Raspberry Pi Imager.

Raspberry Pi Imager

Simplifying the Raspberry Pi experience

For me, one of the most important aspects of the Raspberry Pi experience is trying to make it as easy as possible to get started.  To this end, since launching the first Raspberry Pi, we’ve added a GUI to our operating system, a wizard to help you set up your Raspberry Pi the first time you boot it, and lots of books and magazines to get people up and running.  We’ve even developed the Raspberry Pi Desktop Kit to put all the things you need (yes, Alex, I know – except for a monitor) into a single box to make it as easy as possible!

SD cards can be a bit tricky

Despite all these moves towards more simplicity, when it comes to microSD cards, programming them with your favourite Raspberry Pi operating system has always been a little bit tricky.

The main problem comes from the differences between the operating systems that people’s main computers are likely to use: Windows, macOS, and Linux all use different methods of accessing the SD card, which doesn’t help matters. And, for some new Raspberry Pi users, understanding where to find the latest up-to-date image and how to get it onto the microSD card can be a bit confusing, unless you’ve had prior experience with image-flashing tools such as Etcher.

For that reason, we’ve always suggested that you should buy a pre-loaded NOOBS SD card from your Raspberry Pi Approved Reseller.

But what if you want to re-image an existing card?

Introducing the new Raspberry Pi Imager

Image Utility

No Description

From today, Raspberry Pi users will be able to download and use the new Raspberry Pi Imager, available for Windows, macOS and Ubuntu.

Raspberry Pi Imager


The utility is simple to use and super speedy, thanks to some shortcuts we’ve introduced into the mechanics.

Firstly, Raspberry Pi Imager downloads a .JSON file from our website with a list of all current download options, ensuring you are always installing the most up-to-date version.

Once you’ve selected an operating system from the available options, the utility reads the relevant file directly from our website and writes it straight to the SD card. This speeds up the process quite considerably compared to the standard process of reading it from the website, writing it to a file on your hard drive, and then, as a separate step, reading it back from the hard drive and writing it to the SD card.

During this process, Raspberry Pi Imager also caches the downloaded operating system image – that is to say, it saves a local copy on your computer, so you can program additional SD cards without having to download the file again.

Open source and ready to go!

Download the Raspberry Pi Imager from our downloads page today.

Raspberry Pi Imager is fully open source and was originally written as a modification of the PiBakery tool, later modified and finished by Floris Bos (the original writer of the NOOBS tool and the PiServer tool). You can see Floris’ other software, for data centres, here.

The post Introducing Raspberry Pi Imager, our new imaging utility appeared first on Raspberry Pi.

Play Pong with ultrasonic sensors and a Raspberry Pi | HackSpace magazine

Post Syndicated from Andrew Gregory original https://www.raspberrypi.org/blog/play-pong-with-ultrasonic-sensors-and-a-raspberry-pi-hackspace-magazine/

Day three of our Pong celebration leads us here, to HackSpace magazine’s ultrasonic hack of Eben’s Code the Classics Pong tribute, Boing!

If you haven’t yet bought your copy of Code the Classics, you have until 11:59pm GMT tonight to get £1 off using the discount code PONG. Click here to visit the Raspberry Pi Press online store to secure your copy, and read on to see how you can use ultrasonic sensors to turn this classic game into something a lot more physical.

Over to the HackSpace magazine team…

Code the Classics is an entertaining book for a whole bunch of reasons, but one aspect of it that is particularly exciting to us makers is that it means there are some games out there that are really fun to play, but also written to be easy to understand and have high-quality game art to go along with them. Why does this excite us as makers? Because it makes them ideal candidates for testing out novel DIY games controllers!

Pong

We’re going to start right at the beginning of the book (and also at the beginning of computer game history) with the game Pong. There’s a great chapter on this seminal game in the book, but we’ll dive straight into the source code of our Boing! tribute game. This code should run on any computer with Python 3 (and a few dependencies) installed, but we’ll use a Raspberry Pi, as this has GPIO pins that we can use to add on our extra controller.

Download the code here by clicking the ‘Clone or download’ button, and then ‘Download ZIP’. Unzip the downloaded file, and you should have a directory called Code‑The‑Classics-master, and inside this, a directory called boing-master.

Open a terminal and navigate to this directory, then run:

python3 boing.py

If everything works well, you’ll get a screen asking you to select one or two players – press SPACE to confirm your selection, and have a play.

Hacking Code the Classics

So that’s how Eben Upton designed the game to be played. Let’s put our own spin on it. Games controllers are basically just sensors that take input from the real world in some way and translate that into in-game actions. Most commonly, these sensors are buttons that you press, but there’s no need for that to be the case. You can use almost any sensor you can get input from – it sounds trite, but the main limitation really is your imagination!

We were playing with ultrasonic distance sensors in the last issue of HackSpace magazine, and this sprung to mind a Pong controller. After all, distance sensors measure in one dimension and Pong bats travel in one dimension.

Last issue we learned that the main challenge when using the cheap HC-SR04 sensors with 3.3V devices is that they use 5V, so we need to reduce their output to 3.3V. A simple voltage divider does the trick, and we used three 330Ω resistors to achieve this – see Figure 1 for more details.

There’s support for these sensors in the GPIO Zero Python library. As a simple test, you can obtain the distance with the following Python code:

import gpiozero
import time
sensor = gpiozero.DistanceSensor(echo=15,trigger=14)

while True:
    print(sensor.distance)

time.sleep(0.1)

That will give you a constant read-out of the distance between the ultrasonic sensor and whatever object is in front of it. If you wave your hand around in front of the sensor, you’ll see the numbers changing from 0 to 1, which is the distance in metres.

So far, so straightforward. We only need to add a few bits to the code of our Boing! game to make it interact with the sensor. You can download an updated version of Boing! here, but the changes are as follows.

Add this line to the import statements at the top:

import gpiozero

Add this line to instantiate the distance sensor object at the end of the file (just before pgzrun.go()):

p1_distance = DistanceSensor(echo=15,trigger=14,queue_len=5)

We added the queue_len parameter to get the distances through a little quicker.

Finally, overwrite the p1_controls function with the following:

def p1_controls():
    move = 0
    distance = p1_distance.distance
    print(distance)
    if distance < 0.1:
        move = PLAYER_SPEED
    elif distance > 0.2:
        move = -PLAYER_SPEED
    return move

This uses the rather arbitrary settings of 10 cm and 20 cm to define whether the paddle moves up or down. You can adjust these as required.

That’s all there is to our ultrasonic Pong. It’s great fun to play, but there are, no doubt, loads of other versions of this classic game you can make by adding different sensors. Why not see what you can come up with?

Code the Classics

Today is the last day to get £1 off Code the Classics with the promo code PONG, so visit the Raspberry Pi Press online store to order your discounted copy before 11:59pm GMT tonight.

You can also download Code the Classics as a free PDF here, but the book, oh, the book – it’s a marvellous publication that deserves a physical presence in your home.

The post Play Pong with ultrasonic sensors and a Raspberry Pi | HackSpace magazine appeared first on Raspberry Pi.

Create Boing!, our Python tribute to Pong

Post Syndicated from Alex Bate original https://www.raspberrypi.org/blog/create-boing-our-python-tribute-to-pong/

Following on from yesterday’s introduction to Pong, we’re sharing Boing!, the Python-based tribute to Pong created by Eben Upton exclusively for Code the Classics. Read on to get a detailed look at the code for Boing!

You can find the download link for the Boing! code in the Code the Classics book, available now in a variety of formats. Be sure to stick with today’s blog post until the end, for a special Code the Classics offer.

From Pong to Boing!

To show how a game like Pong can be coded, we’ve created Boing! using Pygame Zero, a beginner-friendly tool for making games in Python. It’s a good starting point for learning how games work – it takes place on a single screen without any scrolling, there are only three moving objects in the game (two bats and a ball), and the artificial intelligence for the computer player can be very simple – or even non-existent, if you’re happy for the game to be multiplayer only. In this case, we have both single-player and two-player modes.

The code can be divided into three parts. First, there’s the initial startup code. We import from other Python modules so we can use their code from ours. Then we check to make sure that the player has sufficiently up-to-date versions of Python and Pygame Zero. We set the WIDTH and HEIGHT variables, which are used by Pygame Zero when creating the game window. We also create two small helper functions which are used by the code.



The next section is the largest. We create four classes: Impact, Ball, Bat, and Game. The first three classes inherit from Pygame Zero’s Actor class, which amongst other things keeps track of an object’s location in the game world, and takes care of loading and displaying sprites. Bat and Ball define the behaviour of the corresponding objects in the game, while Impact is used for an animation which is displayed briefly whenever the ball bounces off something. The Game class’s job is to create and keep track of the key game objects, such as the two bats and the ball.

Further down, we find the update and draw functions. Pygame Zero calls these each frame, and aims to maintain a frame rate of 60 frames per second. Gameplay logic, such as updating the position of an object or working out if a point has been scored, should go in update, while in draw we tell each of the Actor objects to draw itself, as well as displaying backgrounds, text, and suchlike.



Our update and draw functions make use of two global variables: state and game. At any given moment, the game can be in one of three states: the main menu, playing the game, or the game-over screen. The update and draw functions read the state variable and run only the code relevant to the current state. So if state is currently State.MENU, for example, update checks to see if the SPACE bar or the up/down arrows are pressed and updates the menu accordingly, and draw displays the menu on the screen. The technical term for this kind of system is ‘finite state machine’.

The Game class’s job is to create and keep track of the key game objects

The game variable references an instance of the Game class as described above. The __init__ (constructor) method of Game optionally receives a parameter named controls. When we create a new Game object for the main menu, we don’t provide this parameter and so the game will therefore run in attract mode – in other words, while you’re on the main menu, you’ll see two computer-controlled players playing against each other in the background. When the player chooses to start a new game, we replace the existing Game instance with a new one, initialising it with information about the controls to be used for each player – if the controls for the second player are not specified, this indicates that the player has chosen a single-player game, so the second will be computer-controlled.

Two types of movement

In Boing!, the Bat and Ball classes inherit from Pygame Zero’s Actor class, which provides a number of ways to specify an object’s position. In this game, as well as games in later chapters, we’re setting positions using the x and y attributes, which by default specify where the centre of the sprite will be on the screen. Of course, we can’t just set an object’s position at the start and be done with it – if we want it to move as the game progresses, we need to update its position each frame. In the case of a Bat, movement is very simple. Each frame, we check to see if the relevant player (which could be a human or the computer) wants to move – if they do, we either subtract or add 4 from the bat’s Y coordinate, depending on whether they want to move up or down. We also ensure that the bat does not go off the top or bottom of the screen. So, not only are we only moving along a single axis, our Y coordinate will always be an integer (i.e. a whole number). For many games, this kind of simple movement is sufficient. Even in games where an object can move along both the X and Y axes, we can often think of the movement along each axis as being separate. For example, in the next chapter’s game, Cavern, the player might be pressing the right arrow key and therefore moving along the X axis at 4 pixels per frame, while also moving along the Y axis at 10 pixels per frame due to gravity. The movement along each axis is independent of the other.

Able to move at any angle, the ball needs to move at the same speed regardless of its direction

For the Ball, things get a bit more complicated. Not only can it move at any angle, it also needs to move at the same speed regardless of its direction. Imagine the ball moving at one pixel per frame to the right. Now imagine trying to make it move at a 45° angle from that by making it move one pixel right and one pixel up per frame. That’s a longer distance, so it would be moving faster overall. That’s not great, and that’s before we’ve even started to think about movement in any possible direction.

The solution is to make use of vector mathematics and trigonometry. In the context of a 2D game, a vector is simply a pair of numbers: X and Y. There are many ways in which vectors can be used, but most commonly they represent positions or directions.

You’ll notice that the Ball class has a pair of attributes, dx and dy. Together these form a vector representing the direction in which the ball is heading. If dx and dy are 1 and 0.5, then each time the ball moves, it’ll move by one pixel on the X axis and a half a pixel on the Y axis. What does it mean to move half a pixel? When a sprite is drawn, Pygame Zero will round its position to the nearest pixel. So the end result is that our sprite will move down the screen by one pixel every other frame, and one pixel to the right every frame (Figure 1).

We still need to make sure that our object moves at a consistent speed regardless of its direction. What we need to do is ensure that our direction vector is always a ‘unit vector’ – a vector which represents a distance of one (in this case, one means one pixel, but in some games it will represent a different distance, such as one metre). Near the top of the code you’ll notice a function named normalised. This takes a pair of numbers representing a vector, uses Python’s math.hypot function to calculate the length of that vector, and then divides both the X and Y components of the vector by that length, resulting in a vector which points in the same direction but has a length of one (Figure 2).

Vector maths is a big field, and we’ve only scratched the surface here. You can find many tutorials online, and we also recommend checking out the Vector2 class in Pygame (the library on top of which Pygame Zero is built).

Try Boing!

Update Raspbian to try Boing! and other Code the Classics games on your Raspberry Pi.

The full BOING! tutorial, including challenges, further explanations, and a link to the downloadable code can be found in Code the Classics, the latest book from Raspberry Pi Press.

We’re offering £1 off Code the Classics if you order it before midnight tomorrow from the Raspberry Pi Press online store. Visit the store now, or use the discount code PONG at checkout if you make a purchase before midnight tomorrow.

As always, Code the Classics is available as a free PDF from the Wireframe website, but we highly recommend purchasing the physical book, as it’s rather lovely to look at and would make a great gift for any gaming and/or coding enthusiast.

The post Create Boing!, our Python tribute to Pong appeared first on Raspberry Pi.

How to play sound and make noise with your Raspberry Pi

Post Syndicated from Andrew Gregory original https://www.raspberrypi.org/blog/how-to-play-sound-and-make-noise-with-your-raspberry-pi/

If your amazing project is a little too quiet, add high-fidelity sound with Raspberry Pi and the help of this handy guide from HackSpace magazine, written by PJ Evans.

The PecanPi HAT features best-in-class components and dual DACs for superior audio reproduction

It’s no surprise that we love microcontrollers at HackSpace magazine. Their versatility and simplicity make them a must for electronics projects. Although a dab hand at reading sensors or illuminating LEDs, Arduinos and their friends do struggle when it comes to high-quality audio. If you need to add music or speech to your project, it may be worth getting a Raspberry Pi computer to do the heavy lifting. We’re going to look at the various audio output options available for our favourite small computer, from a simple buzz, through to audiophile bliss.

Get buzzing

Need to keep it simple and under a pound?
An active buzzer is what you need

The simplest place to start is with the humble buzzer. A cheap active buzzer can be quickly added to Raspberry Pi’s GPIO. It’s surprisingly easy too. Try connecting a buzzer’s red wire (positive) to GPIO pin 22 (Broadcom numbering) and the black wire (ground) to any GND pin. Now, install the GPIO Zero Python library by typing this at the command line:

sudo apt install python3-gpiozero

Create a file called buzz.py in your favourite editor and enter the following:

import time
from gpiozero import Buzzer
buzzer = Buzzer(22)
buzzer.on()
time.sleep(1)
buzzer.off()

Run it at the command line:

python3 buzz.py

You should hear a one-second buzz. See if you can make Morse code sounds by changing the duration of the sleep statement.

Passive but not aggressive

Raspberry Pi computers, with the exception of the Zero range, all have audio output on board. The original Raspberry Pi featured a stereo 3.5mm socket, and all A and B models since feature a four-pole socket that also includes composite video. This provides your cheapest route to getting audio from your Raspberry Pi computer.

A low-cost passive speaker can be directly plugged in to provide sound, albeit probably quieter than you’d like. Of course, add an amplifier or active speaker and you have sound as loud as you like. This is the most direct way of adding sound to your project, but how to get the sound out?

Need a simple solution? USB audio devices come in all shapes and sizes but are mostly plug-and-play

Normally, the Raspbian operating system will recognise that an audio device has been connected and route audio through it. Sometimes, especially if you’ve connected an HDMI monitor with sound capability (e.g. an HDMI TV), sound will not come out of the correct device.

To fix this, open up a terminal window and run sudo raspi-config. When the menu appears, go to Advanced Options and select Audio, then select the option to force the output through the audio jack. You may need to reboot Raspbian for all changes to take effect.

Plug and playback

A USB sound device is another simple choice for audio playback on Raspberry Pi. Literally hundreds are available, and a basic input/output device with better audio quality than the on-board system can be purchased for a few pounds online. Installation tends to be no more complicated than plugging the device into the USB port. You may need to select the new output, as the underlying audio system, ALSA (see the ALSA and PulseAudio section for more), may mute it by default. To fix this, run alsamixer from the command line, press F6 to select the new sound device, and if you see ‘MM’ at the bottom of the volume indicator, press M to unmute and adjust the volume with the cursor keys.

Many DACs also come with on-board amplifiers. Perfect for passive speakers

Unsurprisingly, when choosing your USB sound device, you can start at a few pounds and go right up to professional equipment costing hundreds. As they are low-power, USB devices do not tend to feature amplification, unless they have a separate power source.

Let’s play

The simplest way to play audio on Raspbian is to use OMXPlayer. This is a dedicated hardware-accelerated command-line tool that takes full advantage of Raspberry Pi’s capabilities. It sends audio to the analogue audio jack by default, so playing back an MP3 file is as simple as running:

omxplayer /path/to/audio/file.wav

There are many command-line options that allow you to control how the audio is played. Want the audio to loop forever? Just add --loop to the command. You’ll notice that when it’s running, OMXPlayer provides a user interface of sorts, allowing you to control playback from within the terminal. If you’d just like it to run in the background without user input, run the command like this:

omxplayer --no-keys example.wav &

Here, —-no-keys removes the interface, and the ampersand (&) tells the operating system to run the job ‘in the background’ so that it won’t block anything else you want to do.

OMXPlayer is a great choice for Raspbian, but other players such as mpg321 are available, so find the tool that’s best for you.

Another useful utility is speaker-test. This can produce white noise or vocal confirmation so you can check your speakers are working properly. It’s as simple as this:

speaker-test -t wav -c 2

The first parameter sets the sound to be a voice, and the -c tests stereo channels only: front left and front right.

Phat Beats

If space is an issue, a Raspberry Pi 4, amplifier, and speaker may not be what you have in mind. After all, your cool wearable project is going to be problematic if you’re trailing an amplifier on a cart with a 50-metre extension lead powering everything. Luckily, the clever people at Pimoroni have you covered. The Speaker pHAT is a Raspberry Pi Zero-sized HAT that not only adds audio capability to the smallest of the Raspberry Pi family, but also sports a 3 W speaker. Now you can play any audio with a tiny device and a USB battery pack.

Small, cheap, and fun, the Speaker pHat features a 3 W speaker and LED VU meter

The installation process is fully automated, so no messing around with drivers and config files. Once the script has completed, you can run any audio tool as before, and the sound will be routed through the speaker. No, the maximum volume won’t be troubling any heavy metal concerts, but you can’t knock the convenience and form factor.

Playing the blues

An easy way to get superior audio quality using a Raspberry Pi computer is Bluetooth. Recent models such as the 3B, 4, and even the Zero W support Bluetooth devices, and can be paired with most Bluetooth speakers, even from the command line. Once connected, you have a range of options on size and output power, plus the advantage of wireless connectivity.

Setting up a Bluetooth connection, especially if you are using the command line, can be a little challenging (see the Bluetooth cheatsheet section). There is a succinct guide here: hsmag.cc/N6p2IB. If you are using Raspbian Desktop, it’s a lot easier. Simply click on the Bluetooth logo on the top-right, and follow the instructions to pair your device.

If you find OMXPlayer isn’t outputting any audio, try installing mpg321:

sudo apt install mpg321

And try again:

mpg321 /path/to/audio/file.mp3

But seriously

If your project needs good audio, and the standard 3.5 mm output just isn’t cutting it, then it’s time to look at the wide range of DACs (digital-to-analogue converters) available in HAT format. It’s a crowded market, and the prices vary significantly depending on what you want from your device. Let’s start at the lower end, with major player HiFiBerry’s DAC+ Zero. This tiny HAT adds 192kHz/24-bit playback via two RCA phono ports for £12.50. If you’re serious about your audio, then you can consider the firm’s full HAT format high-resolution DAC+ Pro for £36, or really go for it with the DSP (digital sound processing) version for £67. All of these will require amplification, but the sound quality will rival audio components of a much higher price.

Money no object? The Allo Katana is a monster DAC, and weighs in at £240, but outperforms £1000 equivalents

If money is no object and your project requires the best possible reproduction, then you can consider going full audiophile. There are some amazing high-end HATs out there, but one of the best-performing ones we’ve seen is the PecanPi DAC. Its creator Leonid Ayzenshtat sourced each individual component carefully, always choosing the best-in-class. He even used a separate DAC for each audio channel. The resulting board may make your wallet wince at around £200 for the bare board, but the resulting audio is good enough to be used in professional recording studios. If you’ve restored a gorgeous old radio back to showroom condition, you could do a lot worse than add the board in with a great amp and speaker.

ALSA and PulseAudio

There’s often confusion between these two systems. Raspbian comes pre-installed with ALSA (Advanced Linux Sound Architecture), which is the low-level software that makes sound work. It comes with a range of utilities to control output device, volume, and more. PulseAudio is a software layer that sits on top of ALSA to provide more features, including streaming capabilities. Chances are, if you need to do something a bit more clever than just play audio, you’ll need to install a PulseAudio server.

Bluetooth cheatsheet

If you want to pair a Bluetooth audio device (A2DP) on the command line, it can be a little hairy. Here’s a quick guide:

First-time installation:

sudo apt-get install pulseaudio pulseaudio-module-bluetooth
sudo usermod -G bluetooth -a pi
sudo reboot

Start the PulseAudio server:

pulseaudio --start

Run the Bluetooth utility:

bluetoothctl

Put your speaker into pairing mode. Now, within the utility, run the following commands (pressing Enter after each one):

power on
agent on
scan on

Now wait for the list to populate. When you see your device…
pair <dev>
Where <dev> is the displayed long identifier for your device. You can just type in the first few characters and press Tab to auto-complete. Do the same for the following steps.

trust <dev>
connect <dev>

Wait for the confirmation, then enter:

quit <dev>

Now try to play some audio using aplay (for WAV files) or mpg321 (for mp3). These instructions are adapted from the guide by Actuino at hsmag.cc/N6p2IB.

File types

There are command-line players available for just about every audio format in common use. Generally, MP3 provides the best balance of quality and space, but lower bit-rates result in lower sound quality. WAV is completely uncompressed, but can eat up your SSD card. If you don’t want to compromise on audio quality, try FLAC, which is identical in quality to WAV, but much smaller. To convert between audio types, consider installing FFmpeg, a powerful audio and video processing tool.

HackSpace magazine

This article comes direct from HackSpace magazine issue 28, out now and available in print from your local newsagent, the Raspberry Pi Store in Cambridge, and online from Raspberry Pi Press.

If you love HackSpace magazine as much as we do, why not have a look at the subscription offers available, including the 12-month deal that comes with a free Adafruit Circuit Playground! Subscribers in the USA can now get a 12-month subscription for $60 when joining by the end of March!

And, as always, you can download the free PDF from the Raspberry Pi Press website.

The post How to play sound and make noise with your Raspberry Pi appeared first on Raspberry Pi.

How to use an LED with Raspberry Pi

Post Syndicated from Alex Bate original https://www.raspberrypi.org/blog/how-to-use-an-led-with-raspberry-pi/

Learn how to use an LED with Raspberry Pi in our latest How to use video on YouTube.

HOW TO USE an LED with Raspberry Pi

Subscribe to our YouTube channel: http://rpf.io/ytsub Help us reach a wider audience by translating our video content: http://rpf.io/yttranslate Buy a Raspberry Pi from one of our Approved Resellers: http://rpf.io/ytproducts Find out more about the #RaspberryPi Foundation: Raspberry Pi http://rpf.io/ytrpi Code Club UK http://rpf.io/ytccuk Code Club International http://rpf.io/ytcci CoderDojo http://rpf.io/ytcd Check out our free online training courses: http://rpf.io/ytfl Find your local Raspberry Jam event: http://rpf.io/ytjam Work through our free online projects: http://rpf.io/ytprojects Do you have a question about your Raspberry Pi?

Using LEDs

LEDs (light-emitting diodes) are incredibly useful in digital making projects. You can use one to indicate whether a script is running or when an action can take place, or as decoration, and for so much more besides.

Blinking an LED with the help of Raspberry Pi has become a rite of passage for new digital makers: it’s the physical equivalent of the ‘hello world’ program! Therefore, it’s the first thing that the participants in our Picademy training, and many young people in physical computing sessions at coding clubs in our networks, learn how to do.

Follow the steps in our latest How to use video to learn how to control an LED with your Raspberry Pi, and go get making.

More Raspberry Pi videos

You can find the How to use YouTube playlist here, and you can subscribe to our channel and never miss a video!

And, while you’re in a subscribe-y mood, also subscribe to the Raspberry Pi Press YouTube channel, the home of all content from The MagPi, HackSpace magazine, WireFrame, Custom PC, and more.

The post How to use an LED with Raspberry Pi appeared first on Raspberry Pi.

USA magazine subscriptions offer: 48% off standard prices

Post Syndicated from Alex Bate original https://www.raspberrypi.org/blog/usa-magazine-subscriptions-offer-48-off-standard-prices/

Today we’re launching a time-limited special offer on subscriptions to HackSpace magazine and The MagPi magazine for readers in the USA, saving you a whopping 48% compared to standard overseas subscriptions. We want to help as many people as possible get their hands on our fantastic publications.

Starting today, you can subscribe to these magazines for the discounted price of $60 a year – just $5 per issue. Not only will you receive twelve issues direct to your door, but you’ll also receive a free gift and save up to 35% compared with newsstand prices!

You’ll need to be quick – this discounted offer is only running until 31 March 2020.

HackSpace magazine

HackSpace magazine is packed with projects for fixers and tinkerers of all abilities. We’ll teach you new techniques and give you refreshers on familiar ones, from 3D printing, laser cutting, and woodworking to electronics and the Internet of Things. HackSpace magazine will inspire you to dream bigger and build better.

Your $60 subscription will get you twelve issues per year and a free Adafruit Circuit Playground Express, worth $25. Click here to subscribe today!

The MagPi magazine

The MagPi is the official Raspberry Pi magazine. Written by and for the community, it’s packed with Raspberry Pi-themed projects, computing and electronics tutorials, how-to guides, and the latest news and reviews.

Your $60 subscription will get you twelve issues per year and a free Raspberry Pi Zero W with accessories. Click here to subscribe today!

The post USA magazine subscriptions offer: 48% off standard prices appeared first on Raspberry Pi.