Printable Keycaps Keep The AlphaSmart NEO Kicking

Today schools hand out Chromebooks like they’re candy, but in the early 1990s, the idea of giving each student a laptop was laughable unless your zip code happened to be 90210. That said, there was an obvious advantage to giving students electronic devices to write with, especially if the resulting text could be easily uploaded to the teacher’s computer for grading. Seeing an opportunity, a couple ex-Apple engineers created the AlphaSmart line of portable word processors.

The devices were popular enough in schools that they remained in production until 2013, and since then, they’ve gained a sort of cult following by writers who value their incredible battery life, quality keyboard, and distraction-free nature. But keeping these old machines running with limited spare parts can be difficult, so earlier this year a challenge had been put out by the community to develop 3D printable replacement keys for the AlphaSmart — a challenge which [Adam Kemp] and his son [Sam] have now answered.

In an article published on, [Sam] documents the duo’s efforts to design the Creative Commons licensed keycaps for the popular Neo variant of the AlphaSmart. Those who’ve created printable replacement parts probably already know the gist of the write-up, but for the uninitiated, it boils down to measuring, measuring, and measuring some more.

Things were made more complicated by the fact that the keyboard on the AlphaSmart Neo uses seven distinct types of keys, each of which took their own fine tuning and tweaking to get right. The task ended up being a good candidate for parametric design, where a model can be modified by changing the variables that determine its shape and size. This was better than having to start from scratch for each key type, but the trade-off is that getting a parametric model working properly takes additional upfront effort.

A further complication was that, instead of using something relatively easy to print like the interface on an MX-style keycap, the AlphaSmart Neo keys snap onto scissor switches. This meant producing them with fused deposition modeling (FDM) was out of the question. The only way to produce such an intricate design at home was to use a resin MSLA printer. While the cost of these machines has come down considerably over the last couple of years, they’re still less than ideal for creating functional parts. [Sam] says getting their keycaps to work reliably on your own printer is likely going to involve some experimentation with different resins and curing times.

[Adam] tells us he originally saw the call for printable AlphaSmart keycaps here on Hackaday, and as we’re personally big fans of the Neo around these parts, we’re glad they took the project on. Their efforts may well help keep a few of these unique gadgets out of the landfill, and that’s always a win in our book.

Custom Inlaid Retro Keycaps: Clay Is The Way

They say experience is the best teacher, and experience tells us they are right. When [Thomas Thiel] couldn’t find any resources about re-creating the groovy ‘caps of thocky old keebs like the Space Cadet and the C64 (or find any to buy), it was time for a little keycap experimentation.

These babies are printed in black resin and the inlay is made with white air-dry clay. After printing, they are sprayed with acrylic, and then [Thomas] works a generous amount of clay into the grooves and seals the whole thing with clear spray. [Thomas] soon figured out that the grooves had to be pretty deep for this to work right — at least 1 mm. And he had better luck thick fonts like Arial Black instead of thin fonts.

Of course, as [Thomas] mentions, you’re not restricted to white or even air-dry clay. You could go nuts with colored clay and make a retro-RGB clackable rainbow.

Still not tactile or custom enough for you? These hand-stitched keycaps are technically re-legendable, though it would take a considerable amount of time.

Handmade Keyboards For Hands

There were some truly bizarre computer keyboards in the 1980s and 90s. The Maltron keyboard was a mass of injection-molded plastic with two deep dishes for all the keys. The Kinesis Advantage keyboard was likewise weird, placing the keys on the inside of a hemisphere. This was a magical time for experimentations on human-computer physical interaction, the likes of which we haven’t seen since.

Now, though, we have 3D printers, easy to use microcontrollers, and Digikey. We can make our own keyboards, and make them in any shape we want. That’s what [Andrey]’s doing. The 32XE is an ergonomic keyboard and trackball combo made for both hands.

The keyboard has curved palm rests, a trackball under the right thumb, and is powered by the ever popular DIY mechanical keyboard microcontroller, the Teensy 2.0. This keyboard is equipped with a trackball, and that means [Andrey] needed a bit of extra electronics to handle that. The mouse/trackball sensor is built around the ADNS-9800 laser motion sensor conveniently available on Tindie. This laser mouse breakout board is built into the bottom of the keyboard, with enough space above it to hold a trackball… ball.

Since this is a very strange and completely custom keyboard, normal mechanical keyboard keycaps are out of the question. Instead, [Andrey] 3D printed his own keycaps on an FDM printer. Printing keyboard keycaps on a filament-based printer is extremely difficult — the tolerances for the connector between the switch and cap are tiny, and nearly at the limit of the resolution of a desktop filament printer. [Andrey] is taking it even further with inlaid keyboard legends. He’s created a keycap set with two color legends on two sides of the keycaps. If you’ve ever wanted to print keycaps on a 3D printer, this is a project to study.