Polaroid Gets Thermal Printer and Raspberry Pi

Despite what you may have read in the comments, we here at Hackaday are not unaware that there’s something of a “Pi Fatigue” brewing. Similar to how “Arduino” was once a dirty word around these parts, projects that are built around the world’s most popular Linux SBC are occasionally getting dismissed as lazy. Hacker crams Raspberry Pi into an old electronic device, applies hot glue liberally, posts a gallery on Imgur, and boom! Lather, rinse, repeat.

We only mention this because the following project, despite featuring the Raspberry Pi Zero grafted into a vintage Polaroid camera, is anything but lazy. In the impeccably detailed and photographed write-up, [mitxela] explains how the Pi Zero and a thermal camera recreated the classic Polaroid experience of going from shutter button to physical picture in seconds. The workmanship and attention to detail on this build is simply phenomenal, and should quell any doubts our Dear Readers may have about Raspberry Pi projects. For now, anyway.

The video after the break will show you the modded camera in operation and goes over a few highlights of the build, but for this one you really should take the time to read the entire process start to finish. [mitxela] starts off by disassembling the Polaroid camera, complete with plenty of fantastic pictures that show how this legendary piece of consumer electronics was put together. If you’ve never seen the inside of one of these cameras, you might be surprised to see what kind of interesting hardware is lurking underneath that rather unassuming exterior. From the screw-less construction to the circuits with paper substrate, a lot of fascinating engineering went into getting this camera to a mass-market price. Frankly, the teardown alone is worth checking out.

But once the camera has been stripped down to the bare frame, the real fun begins. At the conceptual level, [mitxela] replaces the camera optics with a cheap webcam, the “brains” with a Raspberry Pi Zero, and the film mechanism with the type of thermal printer used for receipts. But how he got it all connected is why this project is so impressive. Nearly every decision made during the design and construction of this camera was for the purposes of reducing boot-time. Nobody wants a camera that takes 30, 15, or even 10 seconds to boot. It has to be available as soon as you need it.

Getting this Linux-powered camera boot up in as little as 2 seconds took a lot of clever software hacks that you’ll absolutely want to check out if you’ve ever considered building an embedded Linux device. You can’t just throw a stock Raspbian image on an SD card and hope for the best. [mitxela] used buildroot to craft a custom Linux image containing only what was needed for the camera to operate, plus a bunch of esoteric tweaks that the Junior Penguin Wrangler would likely never consider. Like shaving a full second off of the boot time by disabling dumping kernel messages to the serial port during startup.

[mitxela] brought his camera to show off at the recent Hackaday London meetup, but it was far from the first time we’ve come across his handiwork. From his servo-powered music box earlier this year to his penchant for tiny MIDI devices, he’s consistently impressed our cold robot hearts.

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I’ll Have a Beer With a Compliment Chaser

[Andrew MacPherson] found out that compliments, even insincere ones, make the recipients feel better. So, he put together a thermal printer and a hilariously large button with an Arduino and created a machine that prints compliments. And where best to put a machine that prints out compliments? The local bar, where else?

An Arduino Nano clone runs the show connected to a thermal printer. The Nano clone didn’t like the 9 volt power supply, so a buck converter was used to reduce the voltage down to 5 volts for the Nano, while the printer gets the full power. During initial trials, the printer was very slow to print and it took [Andrew] a while to adjust the parameters – after tweaking the speed as well as the heating time, he was able to get the printer working without burning the paper or taking forever to print.

Once the machine was working, it was time to add a button. A large, light-up button was connected and glued to the side of the printer. More glue was used (after some “modifications” to the printer chassis) to secure a barrel connector for the power adapter.

[Andrew] decided that since he’s down at his favorite bar quite a lot, he’d set it up there. The customers could push the button and receive a compliment while drowning their sorrows. He got a friend of his who’s a copywriter to come up with some nicely written compliments to print out. The printer was such a hit that the bartender sent [Andrew] a message on Facebook saying so. If you have a thermal printer lying around, you can use this tutorial to connect it to the internet, or, if you don’t have one, you can build your own.

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Reflective Sensor Becomes Kart Racing Lap Counter

Once you have a track and a kart to race on it, what’s missing? A lap counter that can give your lap times in hardcopy, obviously! That’s what led [the_anykey] to create the Arduino-based Lap Timer to help him and his kids trim those precious seconds off their runs, complete with thermal printer for the results.

The hardware uses an infrared break-beam sensor module (a Velleman PEM10D) to detect when a kart passes by. This module is similar to a scaled-up IR reflective object sensor; it combines an IR emitter and receiver on one end, and is pointed at a reflector placed across the track, up to 10 meters away. When a kart breaks the beam, the module reports the event to the rest of the hardware. Only needing electronics on one side allows the unit to be self-contained.

An obvious shortcoming of this system is the inability to differentiate between multiple karts, but for timing a single driver’s performance it does the trick. What’s great about this project is it showcases how accessible hardware is today; a device like this is possible to put together with what are essentially off-the-shelf components available to any hobbyist, using an Arduino as the glue to hold it together. We’d only comment that a red-tinted piece of plastic as an overlay for the red display (and a grey-tinted one for the green) would make the LED displays much easier to read. Still, this is a very clean and well-documented build. See it in action in the video embedded below.

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Instant Camera with This Year’s Hottest Dithering Technique

Digital cameras are great, because you can take thousands of pictures without running out of film. But there’s something to be said for having a tangible image you can hold in your hand. The Polaroid cameras of yesteryear were great for this, but now they’re hard to find and the price per photograph is ludicrously expensive.

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Dithering allows the camera to print a much better image.

Over the past few years, a few people have sought a way to create printed photographs at a lower cost. One of the best ways to do this is to find something much cheaper than Polaroid film — like thermal paper.

[Fabien-Chouteau]’s thermal printing camera isn’t the first — you’ve got the Gameboy Camera/Printer and a few others to thank for that. But it’s a great example of the form. The camera combines an Adafruit thermal receipt printer with an OpenMV camera, both easily sourced, if not exactly cheap. It even adds a ST7735 LCD for live display of the camera’s image, just like consumer-grade cameras!

It’s not just a slapped together kludge of parts bin components, however. While the thermal printer is only capable of printing black or white pixels, its resolution is much higher than the image from the camera. This allows the camera to use a 3×3 block of printed pixels to represent a single pixel from the camera, and with some fancy dithering techniques, can emulate shades of grey quite effectively. It’s tricks like this that really add polish to a project, and make a big difference to the picture quality at the end of the day.

It’s not the first thermal printer camera we’ve seen – [Ch00f]’s woodgrain instant camera build highlighted the issues of careful camera selection when pursuing this type of build.

Video after the break.

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Towards More Interesting Instant Cameras

When [Ch00f] was getting jeans rung up at Nordstroms, he noticed how fast thermal receipt printers can put an image on a piece of paper. This observation isn’t unique to the circles [Ch00f] frequents – there are a few small receipt paper printers out there that connect to the Internet, iPhones, and a whole bunch of other Kickstarter-friendly keyword devices.

Nevertheless, a device that can make a hard copy of an image quickly and cheaply isn’t something you just stop thinking about. After rolling the concept around in his head for a few years, [Ch00f] finally came up with the perfect build – a camera.

The hardware for the build is based around an STM32F4 Discovery board. It’s a bit overpowered for this sort of application, and this is one of [Ch00f]’s first adventures in ARM-land. The rest of the hardware consists of a thermal receipt printer and a JPEG camera, the latter of which replaced a cellphone CMOS camera module that was lost in a move.

A custom camera requires a custom enclosure, and for this [Ch00f] made something remarkable. The entire enclosure is CNC milled out of a beautiful piece of figured walnut. The end result looks far too good for a prototype, but it does polish up nicely with a bit of linseed oil.

Now [Ch00f] has an instant camera that takes the idea of a Polaroid and turns it into something that produces a print for tenths of a cent. There’s a time-lapse function – just a zip tie on the shutter button – filters with the help of highlighters, and the ability to record movies in flipbook format.

It’s a great project, and also something that will make for a great crowdfunding campaign. [Ch00f] has already started work on this. He already has a sleek, modern-looking website that requires far too much scrolling than should be necessary – the first step to a winning Kickstarter. [Ch00f] also learned a lot about ARMs, DMA, dithering, gamma correction, and the JPEG format, but that’s not going to get anyone to open up their wallet. You know what will? A slick video. You’ll find that below.

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Electric Imp Thermal Printer

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If you’re the type of person that doesn’t mind having a pocket/purse full of crumpled receipts, then maybe you should check out this tutorial from [tombrew] on giving a thermal printer internet-connectivity.

For some of us, there’s something kind of cool about thermal printers, but it’s probably not the kind of project you’d want to burn a lot of calories on. As a developer over at Electric Imp, [tombrew] agrees with this statement, but since the Electric Imp contains both a WiFi module and processor built in, it makes it pretty easy to get your thermal printer printing off the daily weather, stock prices, news headlines, etc… In fact, the claim here is that you could have this project completed before you even finish your morning coffee… knock on wood!

From a hardware standpoint, the project is pretty straight forward; an Electric Imp with breakout board, thermal printer, and a power supply are pretty much all that’s needed. Local communication between the Electric Imp and the thermal printer is accomplished through a simple serial interface. With the roll-out of the new Electric Imp IDE a few months back, we were introduced to ‘Agents’. This is kind of a neat concept, and this tutorial breaks everything down, but basically the agent is server-side code that runs in the ‘ImpCloud’, thus giving your Electric Imp more power and capabilities to deal with complex APIs. Also, handling images (like something you want to print) can take up a ton of memory, so for this project, the agent is used to send down slices of the image you want to print one at a time. This project is just the beginning of what [tombrew] has planned, so we can’t wait to see more insanely detailed tutorials.

Put in pocket change, get bitcoins

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[gbg] put together a neat little project to get people familiarized with Bitcoins. A lot of techies know what Bitcoins are, but the impetus to download the Bitcoin client and start mining is a bit too much for some. [gbg] has a solution for this – a Bitcoin vending machine. Just dump your pocket change in the coin slot, and out comes a QR code that allows you to add Bitcoins to your wallet.

Inside this Bitcoin briefcase is a Raspberry Pi that connects to a local WiFi connection. Every five seconds, the Raspi looks at the current conversion rate of USD to Bitcoins. Once coins are deposited into the briefcase, a receipt complete with a scannable QR code is printed on a small thermal printer.

When [gbg] took this to the latest DEFCON, a lot of people were interested in the project and started shoveling change into the machine. So many people were interested that [gbg] and his compatriots are planning on turning this into a proper open-source device, complete with a bill reader and possibly an ASIC miner so the Pi can sell the coins it produces.

Check out the video below for some more info.

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