The first prototype: part 3

The polymer-clay experiment was less than successful. The material is too soft and strengthening it with chicken wire is unpractical. But more importantly, the whole idea appeared flawed, as it was very hard to type with this prototype. No worries though, we’ve learnt a lot in the process ans started working on version 2.0 of the prototype with renewed enthousiasm.

wit-plastic toetsenbord case, getoond met twee handen die er op rusten
We decided to abandon the idea of two separate parts, and assume a tilted hand position that results in less strain on the wrists (as seen in the picture to the side).

Twee metalen profielen met draadeinden er tussen geschroefd. Op de draadeinden zijn schakelaars en langwerpige plastic toetsen gemonteerd.
Positioning the switches on wire ends turned out to be a good idea. Together with some sheet metal profiles, this provides a flexible positioning system. We decided to include the keys themselves in this design, which makes it easier to position them relative to the microswitches. It still needs some fine-tuning, some keys snag, but that’s nothing that can’t be solved with a few rings or maybe remaking a couple of keys.

Wit plastic toetsenbord, waarin getoond wordt hoe de toetsen er in passen. This picture shows how it all comes together. The key unit hasn’t been fastened to the case yet at this time though. The angle and placement of the keys relative to the case have to be rather precise because our method of producing the case is rather imprecise right now. It’s been guess work. Once we are finished with prototyping, we can switch to a more robus production process, which should remove this problem entirely.

As for building materials, we switched from plymer clay to polymorph, also known as friendly plastic. You can find it in hot glue guns for example. At 60 degrees celsius this plastic becomes moldeable, and at 90 degrees celsius, it turns into glue. This makes it an ideal prototyping material, as it’s moldeable by hand, and infinitely so (it doesn’t degrade after re-heating). Aditionally, it’s non-toxic and biodegradeable. The only downside it that it’s unsuitable for use in hot environments. If you leave it out in the sun behind a window, it might just lose it’s shape. It took us a while to discover some knacks for working with this material, the most important being the use of a hot air gun instead of hot water for heating it.

We’ve come a long way in a year, but not as far as we would have liked. At least there is progress! What needs to happen now?

The key/switch block needs to be fastened to the case. After that, the electronics need to be soldered in place so we can continue testing and developing the code. Once that’s done, we need to put two keys under the left thumb, and a trackball under the right. Then it’s ready for use, and we only need a name (and a more reliable production process).

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