Tindie

There is probably a reasonable percentage of the Tindie blog readership who appreciate the glow of a Nixie tube. However lovely they are it’s fair to say they can be a little tricky to work with on the average modern and mostly digital home workbench. This Plexiglass Digit module circumvents the challenges of delivering the classic Nixie look with modern addressable LEDs.

Supplied assembled, these excellent modules are essentially a stack of layered Plexiglas with each layer laser-etched with a number. The base of the unit contains an array of WS2812 addressable LEDs all connected to the 3-pin header connector. With a little power and your choice of a microprocessor, you can address LEDs directly under certain Plexiglas panels to light the laser-engraved number. A big advantage is not having to work with the high voltage required to drive real Nixie tubes, which can be both a hassle to get working and also a safety issue, especially if you are working with younger makers.

The beauty of this approach is the light doesn’t bleed to other layers, and you get a clean crisp number. They do have a slightly different look than traditional Nixies – the digits almost look like miniature micro-LEDs floating in mid-air. Of course, this means you can include these modules in all manner of projects to get a heavily tuneable Nixie-like display. Set in a 3D printed case clamped with threaded studs which are terminated at the top with round-headed hex nuts, these modules scream out for a steampunk-style clock, or the display for your next time machine build!

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Digital calipers have been an important tool in machine shops and hackerspaces for a long time now. Being able to quickly get an accurate length measurement can greatly speed up design and prototyping. While many low-end calipers output their measurement over a serial port, MuTko wanted to make a truly hackable pair of calipers from the ground up.

Of course, the digital variety descended from the much older dial or scale calipers. These gave just as much accuracy, but reading scale calipers in particular took a few seconds longer, and when taking many measurements this could add up quickly. Digital calipers come in a wide range of accuracy and price points and are all based on the same concept: a row of PCB traces on the stationary caliper emit a signal that measures the movement and direction of the opposite caliper using capacitive coupling.

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I’m old enough to remember the pre-smartphone heyday of the PDA. It was a great era with a large diversity of devices. I was a Palm fan and still have a drawer full of old handhelds that I’m reluctant to ever get rid of. Of course, like any technology, the PDA movement came armed with a lot of peripherals and accessories, with a common add-on for your device being a folding keyboard. Often these came with either some kind of physical connector or used IR to hook up to your PDA. These devices weren’t cheap so lots of the older folding keyboards are of excellent quality. This Bluetooth module enables you to convert numerous older folding keyboards to be compatible with your modern smartphone.

The currently supported folding keyboard models are the HP or Compaq G750, the Dell G7L0 and the Treo G740 with different module options for each. For all these folding keyboards the installation is similar in that you replace the old docking connector in the keyboard with the new module. Once fitted the keyboard will function as a Bluetooth or a wired USB-C keyboard and can be used wirelessly with any host that supports BLE/Bluetooth 4.0 and later.

The module contains a small battery which can be recharged via the USB connector with charge and power LEDs providing feedback. The project creator offers a neat customisation service for the firmware. If you have a non US keyboard variant or want to otherwise customise the keyboard mapping it just takes a message or two after placing your order.

It’s great to see projects like this on Tindie. It’s so important to try and reduce the amount of e-waste hitting landfill and often, with a little effort to modernise older technology, you’ll end up with a great device that’s also a good conversation starter!

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With Hackaday’s Supercon in the rearview mirror for another year, I wanted to take the time to highlight some of the great SAOs that came out of the Hackaday SAO Contest for Supercon. Simple Add-Ons (hastily renamed Supercon Add-Ons for the event) are little circuits that you attach to your conference badge using a standard, simple 6-pin header. In this case, it’s the Etch-sAo-Sketch, coming to you from the same designer who created the core memory-based SAO.

The Etch-sAo-Sketch is a great idea for an add-on — something simple, yet entertaining and effective as a badge accessory. It has two potentiometers for the X/Y controls, but also has a 3-axis accelerometer. This SAO makes great use of the I2C bus, which was something the contest wanted to highlight. This add-on depends on the badge’s microcontroller to drive it. The OLED and accelerometer use the I2C bus, and the two pots connect via ADC inputs on the accelerometer as well as the two GPIO pins.

Pick one up while they last and use them to display info about yourself or your company, or have it draw random stick figures until someone touches the knobs — there are a lot of possibilities here! It can even be used as a general display output for any other app running on the badge.

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You may well have seen the Micro Journal device before as it’s featured heavily over on Hackaday and been picked up by lots of sites. It’s a fabulous concept for those looking to dramatically reduce distraction whilst writing. Built around an ESP32 microcontroller and a display with an SD card, slot the Micro Journal adds mechanical keyswitches to round out this chic portable device. Often sold as a complete device, it’s great to see this Micro Journal DIY Kit version hit the Tindie shelves.

The kit supplies the majority of the bill of materials needed to create a revision 6 build of the Micro Journal. This includes the custom PCB for the mechanical keyboard, the enclosure parts, the ESP32, the display and SD card holder, the battery holder and all the fixings and fasteners. You’ll need to add an 18650 cell which are pretty common to source; you’ll also need to add the Cherry MX (or compatible) keyswitches and keycaps of your choice to round out the build.

The onboard SD card acts as local storage and, as Micro Journal is all text based, even a tiny 2GB card is going to be able to contain an individual’s lifetime of work. Yes, it will hold around 400 million words! For ease of use though you can set up Micro Journal to sync to your Google Drive (and, presumably, other similar services) meaning your work is near instantly available for further editing.

An 18650 cell will give around 30 hours of distraction free writing time and due to the nature of the ESP32 and firmware the device is instant on, meaning it’s ready whenever and wherever you are when inspiration strikes.  You’ll need a few basic tools like screwdrivers and a glue gun to assemble the kit but the build process and the whole project is well documented. Just check out the GitHub and documentation links on the product page!

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If you’ve even just skirted the periphery of badge life culture, you’ll know of SAO, or Simple Add Ons. They are small boards that add some decorative or functional features to many conference badges with a compatible SAO 6-pin connector. The six pins are a 3.3V supply and ground, a pair of GPIO and an I2C bus. If you are working on a SAO that uses more than just the power pins it can be cumbersome to have to use a conference badge for testing and development. The SAO Demo Controller solves this with a small standalone RP2040-based SAO development board.

Supplied in kit form, the included RP2040- Zero is hooked up to a custom PCB and there are two SAO connectors oriented at 90 degrees to each other. This is a simple but fantastic feature that accommodates a wide variety of SAO form factors. There is also a pair of qwiic/STEMMA QT sockets on board making it trivial to add further I2C devices for experimentation and development.

All the pins of the RP2040-Zero are broken out and the unit is powered via the USB C connector. On board the RP2040-Zero there is an RGB LED visible which can be utilised as a power indicator or for other feedback. It’s a perfect device for SAO development if you aren’t lucky enough to have a SAO equipped conference badge, but it also could be handy when doing simple demonstrations or for simply showing off your SAO collection. Bring one of these along to Supercon in case someone has trouble with their SAO at the last minute!

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The CardKB from M5Stack is a useful, tiny keyboard. With it’s small low-profile tactile switches and its credit card footprint, it’s become a popular choice for small builds requiring keyboard input. This Silicone Cover for CardKB adds a layer of luxury and protection to your tiny keyboard.

Whilst the CardKB isn’t included in this product it’s worth noting a few details about the CardKB itself. It’s primarily a keyboard layout with an I2C interface via a Grove connector. It can be programmed via the Arduino IDE or M5Stack’s UIFlow environments. There’s an addressable RGB LED on board for feedback and interestingly the device is somewhat Lego compatible with two mounting holes being the standard brick size and spacing. With all this functionality in a small package and a low price, it’s become a popular add-on for all manner of projects, both within the M5Stack ecosystem and beyond.

Back to the silicone cover; it covers the entire CardKB PCB apart from the Grove connector, so as well as making the whole device a little softer, it offers some protection to the keyboard. While it doesn’t make the device waterproof, we can imagine this cover combined with some kind of enclosure making for a pretty rugged setup.

The cover is available in black or white silicone with printed characters on all the keycaps. Check it out if you want to add some style to your next pocket computer project!

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It’s truly a testament to the huge computational power we’ve seen come to less expensive microcontrollers over the last years that many of them can generate video signals on the fly. The Pico has recently been used to directly generate DVI for HDMI signalling, and many other microcontrollers can generate VGA using a simple resistor ladder DAC. However, controlling six VGA displays at the same time truly is absolute madness!

In the past few years, an application like this would almost certainly have been done with an FPGA using six VGA design blocks, with a very fast serial interface to a microcontroller to get the display information. The fact that a single ESP32 can do this is truly remarkable and is a testament to the hardware and software skills of bitluni.

Why would you want to control 6 VGA displays at the same time? Well, other than it just being a super cool challenge, you could use the inexpensive ESP32 to generate a large 3×2 tiled screen for message display — bezels can sometimes be an issue in these applications, so your options are to look for VGA displays with tiny bezels or remove the bezels altogether and 3D print a custom retaining bracket for all the display guts.

It looks like there are only a few of these available due to parts shortages right now, but we are really hoping to see a future version released here! bitluni also has a few other VGA-related boards on their store page, so make sure to check them out if you miss out on this batch of the VGA Madness boards.

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While the name “SAO” might generate lots of heated discussion about what it should stand for (Simple Add On, SuperCon Add On, or its earlier more unmentionable name) the premise of what they are is straightforward. These little SAO doohickeys are small circuits that can be added on to SAO-compatible badges, with many hacker/geek/maker conferences badges being SAO compliant, featuring the standard SAO 6-pin header on board. These revamped Rocket SAO are a beautiful example of a fabulous badge adornment using diffused reverse mount NeoPixel addressable RGB LEDs to light and animate parts of the design.

The lovingly crafted PCBs are now available in red, blue or purple solder masks and each one features 3 NeoPixel mounted on the reverse. Aside from the SAO 6-pin connector, there is an ATtiny 412 microcontroller on board with one of the 6-pin connectors used as a UPDI pin to make it easy to program. If you haven’t used the slightly newer ATtiny412 before there are plenty of excellent tutorials online and it’s very similar to using the older ATtiny85 variants, plus they are compatible with the Arduino IDE.

While we can appreciate how good these would look attached to a nice conference badge SAO connector, we love that these also have fittings to attach to a small lanyard or key ring and we think they would look lovely connected as a series of rockets in flight!

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The Open Souce Hardware Association have been a driving force in certifying and promoting open-source hardware. This year, they’re having a fundraising drive and will be doing a live stream on October 2nd to kick off October, which is Open Hardware Month! Part of this stream is about sharing and discussing open hardware projects, talking about how to get projects certified, and also trying to get 100 new OSHWA members.

Supporting OSHWA is a great way to help promote open hardware in general and OSHWA certification in particular! It also helps them organize and put on the annual Open Hardware Summit, which this year was in Montreal, Canada if you missed it. It was an awesome event with tons of great talks and workshops, and the 2025 event promises to be just as amazing. It will be taking place in Edinburgh, Scotland this coming May 30th and 31st, 2025!

I (Tindie Blog editor Alexander Rowsell) will be on the Show & Tell stream at 9:20PM Eastern Time to talk about Tindie’s relationship with Open Hardware and how we promote Certified Open Hardware on the website! Drop by if you have any questions for me, and be sure to tune in and catch all the fabulous people that will be talking about all sorts of cool projects.

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