thermal printer

37 Articles

Old Polaroid Gets A Pi And A Printer

September 27, 2020 by 3 Comments

There’s nothing like a little diversion project to clear the cobwebs — something to carry one through the summer doldrums and charge you up for the rest of the hacking year. At least that’s what we think was up with [Sam Zeloof]’s printing Polaroid retro-conversion project.

Normally occupied with the business of learning how to make semiconductors in his garage, or more recently working on his undergraduate degree in electrical engineering, [Sam], like many of us, found himself with time to spare this summer. In search of a simple, fun project that wouldn’t glaze over the eyes of people when he showed it off, he settled on a printing party camera. The guts are pretty standard fare: a Raspberry Pi and Pi cam, coupled with a thermal receipt printer for instant hardcopy. The donor camera was a Polaroid Pronto from eBay, in good shape on the outside and mostly complete on the inside. A Dremel took care of the latter, freeing up space occupied by all the plastic bits that held the film cartridge and running gear of the film handling system.

The surgery made enough room to squeeze in the Pi Zero and a LiPo battery pack, along with a buck converter. Adding in the receipt printer and its drive board and mounting the Pi cam presented some challenges, but everything fit without breaking the original look and feel of the Polaroid. The camera now produces low-res hardcopy instantly using a dithering algorithm, and store high-resolution images on an SD card for later download. As a bonus, [Sam] included a simulated time and date stamp in the lower corner of the saved images, like those that used to show up on film.

[Sam]’s camera looks like a ton of fun. We’ve seen other Polaroid conversions, including a stunning SX-70 digital upgrade, but this one shines for its simplicity and instant hardcopy.

[via Tom’s Hardware]

Print With Plasma!

August 8, 2020 by 29 Comments

Over the years there have been a variety of methods for a computer to commit its thoughts to paper. Be it a daisy wheel, a dot matrix, a laser, or an inkjet, we’ve all cursed at a recalcitrant printer. There’s another type of printer that maybe we don’t think of quite as often but is workhorse in a million cash registers and parking ticket machines: the thermal printer. These mechanisms can be readily found as surplus items and have made their way into more than one project here over the years. [HomoFaciens] has taken thermal printing a step further by building a plasma printer from scratch that makes use of the thermal paper.

A thermal printer does its job as its name suggests, by burning the image into the paper. It may not deliver the best quality print, but scores on not needing ink ribbons, cartridges, or toner. This DIY version uses an off-the-shelf battery-powered plasma lighter to do the job, mounted on a 3D printed XY printer mechanism driven by two stepper motors. Behind the scenes is an Arduino Uno, which receives its instructions via USB from a command-line program on a Linux box. It’s admitted that this is hardly the pinnacle of printing technology, but it does at least make for a fascinating project. You can see it in action in the video below the break.

This isn’t [HomoFaciens]’ first printer, we’re instantly reminded of this ink drop printer from a few years ago.

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A Hot Printer For Cool Selfies

May 7, 2020 by 12 Comments

Randomly buying some hackable gadgets just because they are cheap and seem potentially interesting for future projects is something that most of us can relate to. It also happened to [fruchti] when he bought five thermal printer modules without any specific purpose for them in mind. It was not until several years later that he put them to good use for his inverse thermal camera project.

The name perfectly summarizes the device’s function which is to convert images to heat instead of the other way around. To put it in a less cryptic manner, [fruchti] built a selfie camera that instantly prints out pictures on thermochromic paper. The project would have been easy to implement on a Raspberry Pi but instead, he chose a more minimalist approach by using an STM32 microcontroller. This involved some challenges because the MCU didn’t have enough RAM to store an entire frame and the camera module came without a FIFO buffer. To capture and store the image data [fruchti] applied a line-by-line dithering algorithm which is described in detail in his accompanying blog post while the corresponding code is available on GitHub. Even though the case was improvised from scrap PCB materials the finished device still looks great. In particular, the fuse holders that are being used to hold the paper roll make it almost steampunk.

Naturally, this is not the first time we have seen thermal printers being used for instant picture taking and it probably won’t be the last.

Warm Up To Cooking With A Recipe-Randomizing Toaster

April 8, 2020 by 10 Comments

Did you get a thermal printer when they were hot stuff, but then your interest cooled when you couldn’t decide what to do with it? Something similar happened to [Sunyecz22], and the poor printer sat unused until that magical day when the perfect use for it popped up — a random recipe receiver in the form of a toaster.

[Sunyecz22] was tired of searching for recipes every week before going to the grocery store. Between the millions of recipe options on the internet and the 1000-word essays that precede them all, the process was like a part-time job. Now all they have to do is push the little lever down and wait for a recipe to get toasted into some thermal paper. It doesn’t print the full recipe, only the essentials, and we love that. You get the name, the prep time, a rating, and a QR code that links to the recipe page.

This toaster runs on a Raspberry Pi Zero W that fetches recipes using the Spoonacular API and sends the deets to the printer. The lever makes use of some old pen springs to activate a limit switch and start the recipe-getting process. We think it would be extra cool if it stayed down until the recipe popped up. Butter your way past the break to see a short demo video.

We must say, this toaster is way more helpful than the talkie toaster from Red Dwarf.

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Little Printer Dispenses Short Stories

February 25, 2020 by 11 Comments

We know how it happens. You buy a fancy new label printer, thinking this is the answer to your disorganized space, but soon entropy grabs the printer as well, and it becomes just another item in the pile. When you find such items later, though, they can spark ideas. The idea that struck [Eric Nichols] was to turn his diminutive thermal printer into a dedicated one for short stories.

Inspired by an article about a vending machine that dispenses stories selected by the reader’s time constraints, [Eric] took on the task of getting his Dymo LabelWriter 400 Turbo working in this new capacity. The first task was finding some continuous roll paper that would fit, because the official stock for this thing is all labels. He got lucky on the first try and a roll of 2 7/16″ receipt paper fit the bill perfectly.

The printer itself doesn’t have much brains; it prints bitmaps 672 bits wide, and as long as you care to make them. While the initial experiments succeeded in printing graphics, [Eric] needed a way to convert his stories to bitmapped text to send to the printer. The human-readable font file format known as BDF (glyph Bitmap Distribution Format) was a perfect fit, since a library to render it was readily available. On top of that, the open-source tool otf2bdf will convert a TrueType (TTF) font to BDF, completing his font-rendering chain.

[Eric] has these printers working with both Linux and windows, either one running on a PC where his software resides, and has it all well-documented on his site. With this in place, it’s simply a matter of coming up with the stories to print. We think it would be perfect for Hackaday dailies!

We’ve seen interesting hacks with disused printers before, like this ascii-art generating cartridge.

A Thermal Typewriter For Burning Thoughts

December 5, 2019 by 15 Comments

There’s a certain charm to old technologies that have been supplanted by newer versions. And we’re not just talking about aesthetic nostalgia this time. With older versions of current technology, you are still connected to the underlying process, and that’s a nice feeling.

Part of the typewriter’s charm is in its instant permanence. These days, its so easy to backspace, delete, and otherwise banish thoughts to the void without giving them a fair trial, though it’s nice not to have to pound the keys to make an impression. At the typewriter, your words are immediately committed to paper, for better or worse. You can usually see them pretty well, although maybe not on the current line, and that is good for letting the words flow without judgment.

[Murtaza Tunio] recently used a thermal POS printer in an art project, but it had since grown cold with disuse. Why not turn it into a typewriter? All it took was a Raspberry Pi, a USB keyboard, and an existing Python library for communicating with these parallel printers. Typing is a bit challenging for a few reasons. For one thing, [Murtaza] has to type five lines before the words become visible. The enter key doesn’t come across for some reason, so a different one had to be assigned. On the upside, [Murtaza] can trigger the paper cutter with a keystroke.

Not too hot on thermal printers? You might find this e-ink typewriter refreshing.

This Clapperboard Prints Movie Posters

June 10, 2019 by 3 Comments

The clapperboard is a device used in video to synchronize audio and video. Its role in movies is well known and its use goes back in one form or another to the 1920s. [Gocivici] is a big movie fan and created a clapperboard that is able to print out posters of recently announced movies when the clapper is clapped.

The poster is not a big, full color job, but rather a black and white one, roughly the size of a movie ticket. [Gocivici] keeps his movie tickets in a journal and wanted to be able to keep small posters in there along with them. A thermal printer is used to print the poster along with the title, the release date, and some information about the movie. In addition to the printer, the hardware involved is a Raspberry Pi, a switch, and an LED. The clapperboard itself is 3d printed and then painted. A bit of metal is used to keep the clappers apart and give a bit of resistance when pressing them together. A nice touch is a metal front, so you can use magnets to keep your posters on the board.

[Gocivici] has detailed build instructions up along with a video (available after the break) showing the printer in action. The 3d models are available as well as the code used to create the posters after grabbing data from TMDb. If you need your clapperboard to be as accurate as possible, take a look at this atomic clock clapperboard.

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