Tag Archives: GPIO Zero

Ms. Haughs’ tote-ally awesome Raspberry Pi bag

Post Syndicated from Alex Bate original https://www.raspberrypi.org/blog/pi-tote-bag/

While planning her trips to upcoming educational events, Raspberry Pi Certified Educator Amanda Haughs decided to incorporate the Pi Zero W into a rather nifty accessory.

Final Pi Tote bag

Uploaded by Amanda Haughs on 2017-07-08.

The idea

Commenting on the convenient size of the Raspberry Pi Zero W, Amanda explains on her blog “I decided that I wanted to make something that would fully take advantage of the compact size of the Pi Zero, that was somewhat useful, and that I could take with me and share with my maker friends during my summer tech travels.”

Amanda Haughs Raspberry Pi Tote Bag

Awesome grandmothers and wearable tech are an instant recipe for success!

With access to her grandmother’s “high-tech embroidery machine”, Amanda was able to incorporate various maker skills into her project.

The Tech

Amanda used five clear white LEDs and the Raspberry Pi Zero for the project. Taking inspiration from the LED-adorned Babbage Bear her team created at Picademy, she decided to connect the LEDs using female-to-female jumper wires

Amanda Haughs Pi Tote Bag

Poor Babbage really does suffer at Picademy events

It’s worth noting that she could also have used conductive thread, though we wonder how this slightly less flexible thread would work in a sewing machine, so don’t try this at home. Or do, but don’t blame me if it goes wonky.

Having set the LEDs in place, Amanda worked on the code. Unsure about how she wanted the LEDs to blink, she finally settled on a random pulsing of the lights, and used the GPIO Zero library to achieve the effect.

Raspberry Pi Tote Bag

Check out the GPIO Zero library for some great LED effects

The GPIO Zero pulse effect allows users to easily fade an LED in and out without the need for long strings of code. Very handy.

The Bag

Inspiration for the bag’s final design came thanks to a YouTube video, and Amanda and her grandmother were able to recreate the make using their fabric of choice.

DIY Tote Bag – Beginner’s Sewing Tutorial

Learn how to make this cute tote bag. A great project for beginning seamstresses!

A small pocket was added on the outside of the bag to allow for the Raspberry Pi Zero to be snugly secured, and the pattern was stitched into the front, allowing spaces for the LEDs to pop through.

Raspberry Pi Tote Bag

Amanda shows off her bag to Philip at ISTE 2017

You can find more information on the project, including Amanda’s initial experimentation with the Sense HAT, on her blog. If you’re a maker, an educator or, (and here’s a word I’m pretty sure I’ve made up) an edumaker, be sure to keep her blog bookmarked!

Make your own wearable tech

Whether you use jumper leads, or conductive thread or paint, we’d love to see your wearable tech projects.

Getting started with wearables

To help you get started, we’ve created this Getting started with wearables free resource that allows you to get making with the Adafruit FLORA and and NeoPixel. Check it out!

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Darth Beats: Star Wars LEGO gets a musical upgrade

Post Syndicated from Janina Ander original https://www.raspberrypi.org/blog/darth-beats/

Dan Aldred, Raspberry Pi Certified Educator and creator of the website TeCoEd, has built Darth Beats by managing to fit a Pi Zero W and a Pimoroni Speaker pHAT into a LEGO Darth Vader alarm clock! The Pi force is strong with this one.

Darth Beats MP3 Player

Pimoroni Speaker pHAT and Raspberry Pi Zero W embedded into a Lego Darth Vader Alarm clock to create – “Darth Beats MP3 Player”. Video demonstrating all the features and functions of the project. Alarm Clock – https://goo.gl/VSMhG4 Speaker pHAT – https://shop.pimoroni.com/products/speaker-phat

Darth Beats inspiration: I have a very good feeling about this!

As we all know, anything you love gets better when you add something else you love: chocolate ice cream + caramel sauce, apple tart + caramel sauce, pizza + caramel sau— okay, maybe not anything, but you get what I’m saying.

The formula, in the form of “LEGO + Star Wars”, applies to Dan’s LEGO Darth Vader alarm clock. His Darth Vader, however, was sitting around on a shelf, just waiting to be hacked into something even cooler. Then one day, inspiration struck: Dan decided to aim for exponential awesomeness by integrating Raspberry Pi and Pimoroni technology to turn Vader into an MP3 player.

Darth Beats assembly: always tell me the mods!

The space inside the LEGO device measures a puny 6×3×3 cm, so cramming in the Zero W and the pHAT was going to be a struggle. But Dan grabbed his dremel and set to work, telling himself to “do or do not. There is no try.”

Darth Beats dremel

I find your lack of space disturbing.

He removed the battery compartment, and added two additional buttons in its place. Including the head, his Darth Beats has seven buttons, which means it is fully autonomous as a music player.

Darth Beats back buttons

Almost ready to play a silly remix of Yoda quotes

Darth Beats can draw its power from a wall socket, or from a portable battery pack, as shown in Dan’s video. Dan used the GPIO Zero Python library to set up ‘on’ and ‘off’ switches, and buttons for skipping tracks and controlling volume.

For more details on the build process, read his blog, and check out his video log:

Making Darth Beats

Short video showing you how I created the “Darth Beats MP3 Player”.

Accessing Darth Beats: these are the songs you’re looking for

When you press the ‘on’ switch, the Imperial March sounds before Darth Beats asks “What is thy bidding, my master?”. Then the device is ready to play music. Dan accomplished this by using Cron to run his scripts as soon as the Zero W boots up. MP3 files are played with the help of the Pygame library.

Of course, over time it would become boring to only be able to listen to songs that are stored on the Zero W. However, Dan got around this issue by accessing the Zero W remotely. He set up an online file upload system to add and remove MP3 files from the player. To do this, he used Droopy, an file sharing server software package written by Pierre Duquesne.

IT’S A TRAP!

There’s no reason to use this quote, but since it’s the Star Wars line I use most frequently, I’m adding it here anyway. It’s my post, and I can do what I want!

As you can imagine, there’s little that gets us more excited at Pi Towers than a Pi-powered Star Wars build. Except maybe a Harry Potter-themed project? What are your favourite geeky builds? Are you maybe even working on one yourself? Be sure to send us nerdy joy by sharing your links in the comments!

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Updates to GPIO Zero, the physical computing API

Post Syndicated from Ben Nuttall original https://www.raspberrypi.org/blog/gpio-zero-update/

GPIO Zero v1.4 is out now! It comes with a set of new features, including a handy pinout command line tool. To start using this newest version of the API, update your Raspbian OS now:

sudo apt update && sudo apt upgrade

Some of the things we’ve added will make it easier for you try your hand on different programming styles. In doing so you’ll build your coding skills, and will improve as a programmer. As a consequence, you’ll learn to write more complex code, which will enable you to take on advanced electronics builds. And on top of that, you can use the skills you’ll acquire in other computing projects.

GPIO Zero pinout tool

The new pinout tool

Developing GPIO Zero

Nearly two years ago, I started the GPIO Zero project as a simple wrapper around the low-level RPi.GPIO library. I wanted to create a simpler way to control GPIO-connected devices in Python, based on three years’ experience of training teachers, running workshops, and building projects. The idea grew over time, and the more we built for our Python library, the more sophisticated and powerful it became.

One of the great things about Python is that it’s a multi-paradigm programming language. You can write code in a number of different styles, according to your needs. You don’t have to write classes, but you can if you need them. There are functional programming tools available, but beginners get by without them. Importantly, the more advanced features of the language are not a barrier to entry.

Become a more advanced programmer

As a beginner to programming, you usually start by writing procedural programs, in which the flow moves from top to bottom. Then you’ll probably add loops and create your own functions. Your next step might be to start using libraries which introduce new patterns that operate in a different manner to what you’ve written before, for example threaded callbacks (event-driven programming). You might move on to object-oriented programming, extending the functionality of classes provided by other libraries, and starting to write your own classes. Occasionally, you may make use of tools created with functional programming techniques.

Five buttons in different colours

Take control of the buttons in your life

It’s much the same with GPIO Zero: you can start using it very easily, and we’ve made it simple to progress along the learning curve towards more advanced programming techniques. For example, if you want to make a push button control an LED, the easiest way to do this is via procedural programming using a while loop:

from gpiozero import LED, Button

led = LED(17)
button = Button(2)

while True:
    if button.is_pressed:
        led.on()
    else:
        led.off()

But another way to achieve the same thing is to use events:

from gpiozero import LED, Button
from signal import pause

led = LED(17)
button = Button(2)

button.when_pressed = led.on
button.when_released = led.off

pause()

You could even use a declarative approach, and set the LED’s behaviour in a single line:

from gpiozero import LED, Button
from signal import pause

led = LED(17)
button = Button(2)

led.source = button.values

pause()

You will find that using the procedural approach is a great start, but at some point you’ll hit a limit, and will have to try a different approach. The example above can be approach in several programming styles. However, if you’d like to control a wider range of devices or a more complex system, you need to carefully consider which style works best for what you want to achieve. Being able to choose the right programming style for a task is a skill in itself.

Source/values properties

So how does the led.source = button.values thing actually work?

Every GPIO Zero device has a .value property. For example, you can read a button’s state (True or False), and read or set an LED’s state (so led.value = True is the same as led.on()). Since LEDs and buttons operate with the same value set (True and False), you could say led.value = button.value. However, this only sets the LED to match the button once. If you wanted it to always match the button’s state, you’d have to use a while loop. To make things easier, we came up with a way of telling devices they’re connected: we added a .values property to all devices, and a .source to output devices. Now, a loop is no longer necessary, because this will do the job:

led.source = button.values

This is a simple approach to connecting devices using a declarative style of programming. In one single line, we declare that the LED should get its values from the button, i.e. when the button is pressed, the LED should be on. You can even mix the procedural with the declarative style: at one stage of the program, the LED could be set to match the button, while in the next stage it could just be blinking, and finally it might return back to its original state.

These additions are useful for connecting other devices as well. For example, a PWMLED (LED with variable brightness) has a value between 0 and 1, and so does a potentiometer connected via an ADC (analogue-digital converter) such as the MCP3008. The new GPIO Zero update allows you to say led.source = pot.values, and then twist the potentiometer to control the brightness of the LED.

But what if you want to do something more complex, like connect two devices with different value sets or combine multiple inputs?

We provide a set of device source tools, which allow you to process values as they flow from one device to another. They also let you send in artificial values such as random data, and you can even write your own functions to generate values to pass to a device’s source. For example, to control a motor’s speed with a potentiometer, you could use this code:

from gpiozero import Motor, MCP3008
from signal import pause

motor = Motor(20, 21)
pot = MCP3008()

motor.source = pot.values

pause()

This works, but it will only drive the motor forwards. If you wanted the potentiometer to drive it forwards and backwards, you’d use the scaled tool to scale its values to a range of -1 to 1:

from gpiozero import Motor, MCP3008
from gpiozero.tools import scaled
from signal import pause

motor = Motor(20, 21)
pot = MCP3008()

motor.source = scaled(pot.values, -1, 1)

pause()

And to separately control a robot’s left and right motor speeds with two potentiometers, you could do this:

from gpiozero import Robot, MCP3008
from signal import pause

robot = Robot(left=(2, 3), right=(4, 5))
left = MCP3008(0)
right = MCP3008(1)

robot.source = zip(left.values, right.values)

pause()

GPIO Zero and Blue Dot

Martin O’Hanlon created a Python library called Blue Dot which allows you to use your Android device to remotely control things on their Raspberry Pi. The API is very similar to GPIO Zero, and it even incorporates the value/values properties, which means you can hook it up to GPIO devices easily:

from bluedot import BlueDot
from gpiozero import LED
from signal import pause

bd = BlueDot()
led = LED(17)

led.source = bd.values

pause()

We even included a couple of Blue Dot examples in our recipes.

Make a series of binary logic gates using source/values

Read more in this source/values tutorial from The MagPi, and on the source/values documentation page.

Remote GPIO control

GPIO Zero supports multiple low-level GPIO libraries. We use RPi.GPIO by default, but you can choose to use RPIO or pigpio instead. The pigpio library supports remote connections, so you can run GPIO Zero on one Raspberry Pi to control the GPIO pins of another, or run code on a PC (running Windows, Mac, or Linux) to remotely control the pins of a Pi on the same network. You can even control two or more Pis at once!

If you’re using Raspbian on a Raspberry Pi (or a PC running our x86 Raspbian OS), you have everything you need to remotely control GPIO. If you’re on a PC running Windows, Mac, or Linux, you just need to install gpiozero and pigpio using pip. See our guide on configuring remote GPIO.

I road-tested the new pin_factory syntax at the Raspberry Jam @ Pi Towers

There are a number of different ways to use remote pins:

  • Set the default pin factory and remote IP address with environment variables:
$ GPIOZERO_PIN_FACTORY=pigpio PIGPIO_ADDR=192.168.1.2 python3 blink.py
  • Set the default pin factory in your script:
import gpiozero
from gpiozero import LED
from gpiozero.pins.pigpio import PiGPIOFactory

gpiozero.Device.pin_factory = PiGPIOFactory(host='192.168.1.2')

led = LED(17)
  • The pin_factory keyword argument allows you to use multiple Pis in the same script:
from gpiozero import LED
from gpiozero.pins.pigpio import PiGPIOFactory

factory2 = PiGPIOFactory(host='192.168.1.2')
factory3 = PiGPIOFactory(host='192.168.1.3')

local_hat = TrafficHat()
remote_hat2 = TrafficHat(pin_factory=factory2)
remote_hat3 = TrafficHat(pin_factory=factory3)

This is a really powerful feature! For more, read this remote GPIO tutorial in The MagPi, and check out the remote GPIO recipes in our documentation.

GPIO Zero on your PC

GPIO Zero doesn’t have any dependencies, so you can install it on your PC using pip. In addition to the API’s remote GPIO control, you can use its ‘mock’ pin factory on your PC. We originally created the mock pin feature for the GPIO Zero test suite, but we found that it’s really useful to be able to test GPIO Zero code works without running it on real hardware:

$ GPIOZERO_PIN_FACTORY=mock python3
>>> from gpiozero import LED
>>> led = LED(22)
>>> led.blink()
>>> led.value
True
>>> led.value
False

You can even tell pins to change state (e.g. to simulate a button being pressed) by accessing an object’s pin property:

>>> from gpiozero import LED
>>> led = LED(22)
>>> button = Button(23)
>>> led.source = button.values
>>> led.value
False
>>> button.pin.drive_low()
>>> led.value
True

You can also use the pinout command line tool if you set your pin factory to ‘mock’. It gives you a Pi 3 diagram by default, but you can supply a revision code to see information about other Pi models. For example, to use the pinout tool for the original 256MB Model B, just type pinout -r 2.

GPIO Zero documentation and resources

On the API’s website, we provide beginner recipes and advanced recipes, and we have added remote GPIO configuration including PC/Mac/Linux and Pi Zero OTG, and a section of GPIO recipes. There are also new sections on source/values, command-line tools, FAQs, Pi information and library development.

You’ll find plenty of cool projects using GPIO Zero in our learning resources. For example, you could check out the one that introduces physical computing with Python and get stuck in! We even provide a GPIO Zero cheat sheet you can download and print.

There are great GPIO Zero tutorials and projects in The MagPi magazine every month. Moreover, they also publish Simple Electronics with GPIO Zero, a book which collects a series of tutorials useful for building your knowledge of physical computing. And the best thing is, you can download it, and all magazine issues, for free!

Check out the API documentation and read more about what’s new in GPIO Zero on my blog. We have lots planned for the next release. Watch this space.

Get building!

The world of physical computing is at your fingertips! Are you feeling inspired?

If you’ve never tried your hand on physical computing, our Build a robot buggy learning resource is the perfect place to start! It’s your step-by-step guide for building a simple robot controlled with the help of GPIO Zero.

If you have a gee-whizz idea for an electronics project, do share it with us below. And if you’re currently working on a cool build and would like to show us how it’s going, pop a link to it in the comments.

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