Tag Archives: stepper motor

Enchanting images with Inky Lines, a Pi‑powered polargraph

Post Syndicated from Helen Lynn original https://www.raspberrypi.org/blog/enchanting-images-inky-lines-pi-powered-polargraph/

A hanging plotter, also known as a polar plotter or polargraph, is a machine for drawing images on a vertical surface. It does so by using motors to control the length of two cords that form a V shape, supporting a pen where they meet. We’ve featured one on this blog before: Norbert “HomoFaciens” Heinz’s video is a wonderfully clear introduction to how a polargraph works and what you have to consider when you’re putting one together.

Today, we look at Inky Lines, by John Proudlock. With it, John is creating a series of captivating and beautiful pieces, and with his most recent work, each rendering of an image is unique.

The Inky Lines plotter draws a flock of seagulls in blue ink on white paper. The print head is suspended near the bottom left corner of the image, as the pen inks the wing of a gull

An evolving project

The project isn’t new – John has been working on it for at least a couple of years – but it is constantly evolving. When we first spotted it, John had just implemented code to allow the plotter to produce mesmeric, spiralling patterns.

A blue spiral pattern featuring overlapping "bubbles"
A dense pink spiral pattern, featuring concentric circles and reminiscent of a mandala
A blue spirograph-type pattern formed of large overlapping squares, each offset from its neighbour by a few degrees, producing a four-spiral-armed "galaxy" shape where lines overlap. The plotter's print head is visible in a corner of the image

But we’re skipping ahead. Let’s go back to the beginning.

From pixels to motor movements

John starts by providing an image, usually no more than 100 pixels wide, to a Raspberry Pi. Custom software that he wrote evaluates the darkness of each pixel and selects a pattern of a suitable density to represent it.

The two cords supporting the plotter’s pen are wound around the shafts of two stepper motors, such that the movement of the motors controls the length of the cords: the program next calculates how much each motor must move in order to produce the pattern. The Raspberry Pi passes corresponding instructions to two motor circuits, which transform the signals to a higher voltage and pass them to the stepper motors. These turn by very precise amounts, winding or unwinding the cords and, very slowly, dragging the pen across the paper.

A Raspberry Pi in a case, with a wide flex connected to a GPIO header
The Inky Lines plotter's print head, featuring cardboard and tape, draws an apparently random squiggle
A large area of apparently random pattern drawn by the plotter

John explains,

Suspended in-between the two motors is a print head, made out of a new 3-d modelling material I’ve been prototyping called cardboard. An old coat hanger and some velcro were also used.

(He’s our kind of maker.)

Unique images

The earlier drawings that John made used a repeatable method to render image files as lines on paper. That is, if the machine drew the same image a number of times, each copy would be identical. More recently, though, he has been using a method that yields random movements of the pen:

The pen point is guided around the image, but moves to each new point entirely at random. Up close this looks like a chaotic squiggle, but from a distance of a couple of meters, the human eye (and brain) make order from the chaos and view an infinite number of shades and a smoother, less mechanical image.

An apparently chaotic squiggle

This method means that no matter how many times the polargraph repeats the same image, each copy will be unique.

A gallery of work

Inky Lines’ website and its Instagram feed offer a collection of wonderful pieces John has drawn with his polargraph, and he discusses the different techniques and types of image that he is exploring.

A 3 x 3 grid of varied and colourful images from inkylinespolargraph's Instagram feed

They range from holiday photographs, processed to extract particular features and rendered in silhouette, to portraits, made with a single continuous line that can be several hundred metres long, to generative images spirograph images like those pictured above, created by an algorithm rather than rendered from a source image.

The post Enchanting images with Inky Lines, a Pi‑powered polargraph appeared first on Raspberry Pi.

Digitising film reels with Pi Film Capture

Post Syndicated from Janina Ander original https://www.raspberrypi.org/blog/digitising-reels-pi-film-capture/

Joe Herman’s Pi Film Capture project combines old projectors and a stepper motor with a Raspberry Pi and a Raspberry Pi Camera Module, to transform his grandfather’s 8- and 16-mm home movies into glorious digital films.

We chatted to him about his Pi Film Capture build at Maker Faire New York 2016:

Film to Digital Conversion at Maker Faire New York 2016

Uploaded by Raspberry Pi on 2017-08-25.

What inspired Pi Film Capture?

Joe’s grandfather, Leo Willmott, loved recording home movies of his family of eight children and their grandchildren. He passed away when Joe was five, but in 2013 Joe found a way to connect with his legacy: while moving house, a family member uncovered a box of more than a hundred of Leo’s film reels. These covered decades of family history, and some dated back as far as 1939.

Super 8 film reels

Kodachrome film reels of the type Leo used

This provided an unexpected opportunity for Leo’s family to restore some of their shared history. Joe immediately made plans to digitise the material, knowing that the members of his extensive family tree would provide an eager audience.

Building Pi Film Capture

After a failed attempt with a DSLR camera, Joe realised he couldn’t simply re-film the movies — instead, he would have to capture each frame individually. He combined a Raspberry Pi with an old Super 8 projector, and set about rigging up something to do just that.

He went through numerous stages of prototyping, and his final hardware setup works very well. A NEMA 17 stepper motor  moves the film reel forward in the projector. A magnetic reed switch triggers the Camera Module each time the reel moves on to the next frame. Joe hacked the Camera Module so that it has a different focal distance, and he also added a magnifying lens. Moreover, he realised it would be useful to have a diffuser to ‘smooth’ some of the faults in the aged film reel material. To do this, he mounted “a bit of translucent white plastic from an old ceiling fixture” parallel with the film.

Pi Film Capture device by Joe Herman

Joe’s 16-mm projector, with embedded Raspberry Pi hardware

Software solutions

In addition to capturing every single frame (sometimes with multiple exposure settings), Joe found that he needed intensive post-processing to restore some of the films. He settled on sending the images from the Pi to a more powerful Linux machine. To enable processing of the raw data, he had to write Python scripts implementing several open-source software packages. For example, to deal with the varying quality of the film reels more easily, Joe implemented a GUI (written with the help of PyQt), which he uses to change the capture parameters. This was a demanding job, as he was relatively new to using these tools.

Top half of GUI for Pi Film Capture Joe Herman

The top half of Joe’s GUI, because the whole thing is really long and really thin and would have looked weird on the blog…

If a frame is particularly damaged, Joe can capture multiple instances of the image at different settings. These are then merged to achieve a good-quality image using OpenCV functionality. Joe uses FFmpeg to stitch the captured images back together into a film. Some of his grandfather’s reels were badly degraded, but luckily Joe found scripts written by other people to perform advanced digital restoration of film with AviSynth. He provides code he has written for the project on his GitHub account.

For an account of the project in his own words, check out Joe’s guest post on the IEEE Spectrum website. He also described some of the issues he encountered, and how he resolved them, in The MagPi.

What does Pi Film Capture deliver?

Joe provides videos related to Pi Film Capture on two sites: on his YouTube channel, you’ll find videos in which he has documented the build process of his digitising project. Final results of the project live on Joe’s Vimeo channel, where so far he has uploaded 55 digitised home videos.

m093a: Tom Herman Wedding, Detroit 8/10/63

Shot on 8mm by Leo Willmott, captured and restored by Joe Herman (Not a Wozniak film, but placed in that folder b/c it may be of interest to Hermans)

We’re beyond pleased that our tech is part of this amazing project, helping to reconnect the entire Herman/Willmott clan with their past. And it was great to be able to catch up with Joe, and talk about his build at Maker Faire last year!

Maker Faire New York 2017

We’ll be at Maker Faire New York again on the 23-24 September, and we can’t wait to see the amazing makes the Raspberry Pi community will be presenting there!

Are you going to be at MFNY to show off your awesome Pi-powered project? Tweet us, so we can meet up, check it out and share your achievements!

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The CNC Wood Burner turning heads (and wood, obviously)

Post Syndicated from Alex Bate original https://www.raspberrypi.org/blog/cnc-wood-burner/

Why stick to conventional laser cutters or CNC machines for creating images on wood, when you can build a device to do the job that is a beautiful piece of art in itself? Mechanical and Computer Science student and Imgur user Tucker Shannon has created a wonderful-looking CNC Wood Burner using a Raspberry Pi and stepper motors. His project has a great vinyl-turntable-like design.

Raspberry Pi CNC Wood Burner

Tucker’s somewhat hypnotic build burns images into wood using a Raspberry Pi and stepper motors
GIF c/o Tucker Shannon

A CNC Wood Burner?

Sure! Why not? Tucker had already put the knowledge he acquired while studying at Oregon State University to good use by catching a bike thief in action with the help of a Raspberry Pi. Thus it’s obvious he has the skills he needed to incorporate our little computer into a project. Moreover, his Skittles portrait of Bill Nye is evidence of his artistic flare, so it’s not surprising that he wanted to make something a little different, and pretty, using code.

Tucker Shannon

“Bill Nye, the Skittles Guy”
Image c/o Tucker Shannon

With an idea in mind and sketches drawn, Tucker first considered using an old record player as the base of his build. Having a rotating deck and arm already in place would have made building his project easier. However, he reports on Imgur:

I thought about that! I couldn’t find any at local thrift shops though. Apparently, they’ve become pretty popular…

We can’t disagree with him. Since his search was unsuccessful, Tucker ended up creating the CNC Wood Burner from scratch.

Raspberry Pi CNC Wood Burner

Concept designs
Image c/o Tucker Shannon

Taking into consideration the lumps and bumps of the wood he would be using as a ‘canvas’, Tucker decided to incorporate a pivot to allow the arm to move smoothly over the rough surface.

The code for the make is currently in ‘spaghetti form’, though Tucker is set to release it, as well as full instructions for the build, in the near future.

The build

Tucker laser-cut the pieces for the wood burner’s box and gear out of birch and pine wood. As the motors require 12v power, the standard Raspberry Pi supply wasn’t going to be enough. Therefore, Tucker scavenged for old computer parts , and ended up rescuing a PSU (power supply unit). He then fitted the PSU and the Raspberry Pi within the box.

Raspberry Pi CNC Wood Burner

The cannibalised PSU, stepper motor controller, and Raspberry Pi fit nicely into Tucker’s handmade pine box.
Image c/o Tucker Shannon

Next, he got to work building runners for the stepper motor controlling the position of the ‘pen thing’ that would scorch the image into the wood.

Raspberry Pi CNC Wood Burner

Initial tests on paper help to align the pen
Image c/o Tucker Shannon

After a few test runs using paper, the CNC Wood Burner was good to go!

The results

Tucker has used his CNC Wood Burner to create some wonderful pieces of art. The few examples he’s shared on Imgur have impressed us with their precision. We’re looking forward to seeing what else he is going to make with it!

Raspberry Pi CNC Wood Burner

The build burns wonderfully clean-lined images into wood
Image c/o Tucker Shannon

Your turn

Image replication using Raspberry Pis and stepper motors isn’t a new thing – though doing it using a wood-burning device may be! We’ve seen some great builds in which makers set up motors and a marker pen to create massive works of art. Are you one of those makers? Or have you been planning a build similar to Tucker’s project, possibly with a new twist?

Share your project with us below, whether it is complete or still merely sketches in a notebook. We’d love to see what you’re getting up to!

The post The CNC Wood Burner turning heads (and wood, obviously) appeared first on Raspberry Pi.

Estefannie’s Automated French Press

Post Syndicated from Alex Bate original https://www.raspberrypi.org/blog/estefannie-automated-french-press/

Why press a french press when the french press can press itself? Here’s Estefannie to explain it all…

Internet Button Controlled Automated French Press

Hey World! What’s better than making coffee? Not making coffee. But still drinking coffee. I decided to make my own automated French Press machine. To automate it, I used a Raspberry Pi, a Photon (Internet Button), two stepper motors, wood, glue, and a lot of imagination.

Okay, okay. I’m sure you get it by now. Here at Pi Towers, we love a good coffee hack. In truth, we love any coffee hack. And we also love Estefannie … so you can see where today’s blog is going.

Building an automated french press

For the build, Estefannie uses the Particle Internet Button to tell a wooden castle when it’s ready to press her coffee. Wooden castle? We’ll get there – hold on.

Estefannie Explains it All Raspberry Pi French Press

Wait, I said hold on … never mind.

The Internet Button houses a Photon, a small programmable WiFi development board for Internet of Things (IoT) prototyping. Alongside RGB LEDs, tactile buttons, and an accelerometer, the Internet Button allows wireless control, via the cloud, to the Raspberry Pi. Perfect for the self-pressing french press.

Esteffannie Explains it All Raspberry Pi French Press

Like so…

So, wooden castles? Two wooden castles act as housings for servo-powered screws that raise and lower the french press pressing bar. When the coffee is ready to be pressed, they turn in one direction, lowering the bar. When the press is complete, they turn the other way to raise it, giving access to the perfectly brewed coffee. Everything is controlled using Python code on the Raspberry Pi, triggered by the press of the Internet Button.

Esteffannie Explains it All Raspberry Pi French Press

The button has three states. Green indicates that everything is ready to press. Magenta indicates the four-minute brew time, and a rainbow tells you that your coffee is ready for consumption. Beautiful.

Automate your own

Once you have perfected the basic build, the same rig could be used to automate no end of household chores. How about setting a timer to slowly press tofu? Turning the rig on its side to open and close a door? Or how about raising and lowing the bar much more quickly to plunger the toilet? Too much? Yeah, I thought the same as I typed it.

You can find the code for the build on Estefannie’s Github. I also suggest subscribing to her YouTube channel for more fun tech hacks and Raspberry Pi builds.

Afterthought

If Simone Giertz is the Queen of Sh!tty Robots, is it fair to say that Estefannie is rightly claiming her spot at the Queen of un-Sh!tty ones?

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FlipFrame – the rotating picture frame

Post Syndicated from Alex Bate original https://www.raspberrypi.org/blog/flipframe-rotating-picture-frame/

You know the drill: you fill your digital photo frame with your favourite snaps, watch them flash up one after another and suddenly, ugh… an image appears at a different orientation to the rest. Those black boxes at the sides or top, shrinking the detail, or – even worse – a distorted stretch and skew of faces and landscapes.

Yuck.

Luckily for us, Tim shared his rotating digital picture frame, the FlipFrame, on Hackaday, giving us all the chance to solve this very trying issue.

FlipFrame – A Rotating Digital Picture Frame

I wanted a nice way to display my digital pictures, but I didn’t want to sacrifice the quality of my vertically oriented pictures. I couldn’t find a rotating digital picture so I made my own. The frame is built on a discarded 27″ LCD TV. The slideshow runs on a Raspberry PI 3.

The frame incorporates both a Raspberry Pi and Arduino, the former hosting the images, and notifying the latter when to rotate the frame smoothly via a stepper motor.

The images are stored on an SD card, Tim’s original plan of importing directly from Google Photos having been hindered by API limitations.

FlipFrame

The frame uses a 27” LCD display and speakers, with several 3D-printed and laser-cut parts. Tim has made all files available via Hackaday, along with a component list and brief rundown of how they all fit together.

Have you made something similar? Share your photo frame-based projects with us in the comments below.

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