thermal printer

38 Articles

Get GitHub Tickets IRL With A Raspberry Pi And A Receipt Printer

March 25, 2022 by 15 Comments

Thermal receipt printers are finding their way into all sorts of projects that are well beyond the point-of-sale environment that they normally inhabit. And while we applaud all the creative and artistic uses hackers have found for these little gems, this GitHub physical ticket printer has to be the best use for one yet.

According to [Andrew Schmelyun], seeing a fast-food order pop up on a thermal printer was the inspiration for this build. Maintaining over one hundred GitHub repos as he does, it’s easy for the details of any one bug report or feature request to get lost in the swarm of sticky notes that [Andrew] previously used to keep track of his work. To make it happen, he teamed an Epson thermal printer up to a Raspberry Pi Zero W and worked out the details of sending data to the printer using PHP. Luckily, there’s a library for that — the beauty of GitHub.

With the “Hello, World!” bit out of the way, [Andrew] turned his attention to connecting to GitHub. He set up some webhooks on the GitHub side to send a POST request every time an issue is reported on one of his repos. The POSTs are sent via ngrok to a PHP web server running on the Pi, which formats the data and sends the text to the printer. There’s a short video in the tweet below.

Between the sound of the printer working and the actual dead-tree ticket, it’ll be hard for [Andrew] to miss issues now. We’ve seen thermal printers stuffed into cameras, used to send pictures to Grannie, and even watched them commit suicide slowly, but we say hats off to [Andrew] for his solid work ethic and a fun new way to put a receipt printer to use.

Continue reading “Get GitHub Tickets IRL With A Raspberry Pi And A Receipt Printer” →

Thermal printer with a loop of thermochromic foil inserted in it, printing digits of Pi on the loop.The digits gradually disappear from the foil as it exits the printer.

Celebrating The Infinity Of Pi Day With Thermochromic Foil

March 21, 2022 by 8 Comments

It might take you some time to understand what’s happening in the video that Hackaday alum [Moritz Sivers] shared with us. This is [Moritz]’s contribution for this year’s Pi Day – a machine that shows digits of Pi in a (technically, not quite) infinite loop, and shows us a neat trick we wouldn’t have thought of.

The two main elements of this machine are a looped piece of thermochromic foil and a thermal printer. As digits are marked on the foil by the printer’s heating element, they’re visible for a few seconds until the foil disappears from the view, only to be eventually looped back and thermally embossed anew. The “Pi digits calculation” part is offloaded to Google’s pi.delivery service, a π-as-a-Service endpoint that will stream up to 50 trillion first digits of Pi in case you ever need them – an ESP8266 dutifully fetches the digits and sends them off to the thermal printer.

This machine could print the digits until something breaks or the trillions of digits available run out, and is an appropriate tribute to the infinite nature of Pi, a number we all have no choice but to fundamentally respect. A few days ago, we’ve shown a similar Pi Day tribute, albeit a more self-sufficient one – an Arduino calculating and printing digits of Pi on a character display! We could’ve been celebrating this day for millennia, if Archimedes could just count a little better.

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Sending Pics To Grandma, No Smartphone Needed

January 21, 2022 by 32 Comments

When it comes to keeping in touch with the grandparents, a lack of familiarity with modern technology can get in the way. [palmerabollo] wanted to share photos with his grandmother, but found that it was difficult as she didn’t have a smartphone or an Internet connection to receive photos. Thus, a custom build for grandma was in order! (translated)

To minimise maintenance requirements, the build relies on a thermal receipt printer. Each roll of thermal paper is good for printing off about 150 images before needing a change, so it’s a low-cost, fuss-free solution with no need for ink changeovers.

A Raspberry Pi Zero 2W runs the show, paired with a HAT that provides cellular internet connectivity. Photos are sent over Telegram with some custom Python code that [palmerabollo] put together. The system uses the Python “thermalprinter” library, with the Floyd-Steinberg dithering algorithm baked in allowing nice quality even on the simple thermal printer.

It’s a fun build, and lets [palmerabollo] send his grandmother fun photos and messages without requiring any effort on her part. It’s super cute to see the photos stuck up on the refrigerator, too.

There’s plenty of fun to be had with thermal printers, so don’t be afraid to get stuck in yourself! Video after the break. Continue reading “Sending Pics To Grandma, No Smartphone Needed” →

Mini Wireless Thermal Printers Get Arduino Library (and MacOS App)

September 21, 2021 by 23 Comments

[Larry Bank]’s Arduino library to print text and graphics on BLE (Bluetooth Low Energy) thermal printers has some excellent features, and makes sending wireless print jobs to a number of common models about as easy as can be. These printers are small, inexpensive, and wireless. That’s a great mix that makes them attractive for projects that would benefit from printing out a hardcopy.

It’s not limited to simple default text, either. Fancier output can be done using Adafruit_GFX library-style fonts and options, which sends the formatted text as graphics. You can read all about what the library can do in this succinct list of concise functions.

But [Larry] hasn’t stopped there. While experimenting with microcontrollers and BLE thermal printers, he also wanted to explore talking to these printers from his Mac using BLE directly. Print2BLE is a MacOS application that allows dragging image files into the application’s window, and if the preview looks good, the print button makes it come out of the printer as a 1-bpp dithered image.

Small thermal printers make for neat projects, like this retrofitted Polaroid camera, and now that these little printers are both wireless and economical, things can only get easier with the help of a library like this. Of course, if that’s all starting to look a little too easy, one can always put the thermal back in thermal printing by using plasma, instead.

Coding A Custom Driver For The Adafruit Mini Thermal Printer

June 26, 2021 by 6 Comments

Thermal printers are cool… or, uh, warm actually. They use heat to make images, so they never need ink and they print on receipt rolls. The thermal printer available from Adafruit is a particularly tasty example, as it comes fully documented for the budding hacker. [Ed] is one such person, who set about writing his own driver to use the hardware with Linux on a Raspberry Pi.

The project came about as [Ed] didn’t like the halftone output from the standard Adafruit CUPS driver. Thus, a dithering-capable driver was needed instead. The first step of the project was to get dithering working via running such an algorithm into a custom driver, as well as to vary the heating time of the print head to gain greyscale capability. From there, the driver was integrated with CUPS and could be used with the Linux lp command. Finally, measures to deal with the paper running out were coded in as well.

It’s a fun dive into the nitty-gritty of talking to printers at the low level, something that few of us think about when printing concert tickets in a rush. There’s a lot that goes on to get a page to print successfully, and [Ed]’s work leaves us more respect for everything that goes on to get an image on the paper. The driver is available for keen tinkerers over at Github.

Meanwhile, consider a thermal printer for all your banner-printing needs.

You Won’t Believe How Much Tech Is Hiding In This Desk

April 20, 2021 by 23 Comments

Say what you will about office life: there were definitely some productivity perks, but the coffee is much better at home. Like many of us, [Pierre] has been working from home for the last year or so. And as much as he might enjoy spending so much time in his small Parisian apartment, it lacks many of the amenities of the office such as a scanner, printer, and, you know, a reasonable amount of space in which to work.

Inspired by another build, [Pierre] set out to build his dream desk that is maximum PC power in minimum space. It is chock full of easily-accessible cavities that hide everything you’d expect, plus a few things you don’t, like a flatbed scanner, a printer, a router, and a wireless charging pad. One cavity is dedicated to I/O, and another has three international power sockets. The only thing it doesn’t hide is the 22″ pen display that [Pierre] uses for sketching, signing documents, and occasionally as a second monitor.

A home-brew jig makes consistent dowel drilling much easier.

This desk may look like solid wood, but the top is a veneer that’s glued on to a custom-cut 1mm steel sheet. The inside frame is made of hardwood and so are the legs — one of them has a hidden channel for the only two cords that are even somewhat visible — the power and Ethernet cables. He joined all the frame pieces with dowel rods, and made a 3D-printed and metal-reinforced drilling jig to get the holes just right.

[Pierre] started this build by planning out the components and making meticulous notes about the dimensions of every piece. Then he sketched it and modelled it in FreeCAD to get all the cavities and cable runs correct and ensure good airflow through the desk. After that it was on to woodworking, metalworking, and PCB fab for relocated and hidden display controls and a custom-built amplifier.

It’s obvious that a lot of thought went in to this, and there’s a ton of work appreciate here, so clear off that inferior desk of yours and check out the build video after the break. Wish you had a PC desk? [Pierre] is seriously considering a Kickstarter if enough people show interest.

Are you into minimalism, but don’t want to build something of this magnitude? There’s more than one way to get there.

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ESP8266-Powered Receipt Printer Puts RESTful API On Dead Trees

March 10, 2021 by 1 Comment

Taking his digital information into the real-world, [Davide Gironi] has built his own note transcriber from a point-of-sale receipt printer and an ESP8266.

You’ve seen these receipt printers at the order window of restaurants. A server puts in an order from any of the machines throughout the restaurant and a paper summary spits out for the chef line to start in on (and even cuts itself off from the roll).  Why shouldn’t we have this convenience in our own lives?

The printer communicates using a variant of the Epson Standard Code for Printers, for which [Davide] has written a library and thankfully shared the code. Adding an ESP8266 using a couple voltage regulators and some passive components makes this wireless, except for power. It has all the fun bells and whistles to set up the WiFi credentials and once running, just push the button on the base and it’ll spit out your data.

But wait, where is that data coming from? The web-based settings page lets you configure a URI to the RESTful source of your choosing. (XKCD has one, don’t they?) It also lets you configure header, footer, error messages, and of course your company hacker logo.

One of our favorite receipt-printer moments was when Hackaday editor of yore [Eliot Phillips] brought a selfie receipt printer to Supercon. We couldn’t find any pictures of that one, so we’ll leave you with the excellent hack [Sam Zeloof] pulled off by cramming one of these into a Polaroid camera.

Continue reading “ESP8266-Powered Receipt Printer Puts RESTful API On Dead Trees” →