Weird-feeling breakthrough

Oct 8, 2017 • AKA

As the outdated Hacakday.io page indicates, I spent over a year more or less stuck on my circuit design. The main issue was that it was my first boost / flyback converter, and I did not really understand which variables were critical and which were ancillary. Additionally, sensing current from the high side of the circuit had flummoxed me, and this was a pretty important part of making a board that was suitable to distribute to a larger audience. Recently I had even enlisted the paid help of an EE contractor I know, who (sort of reassuringly) encountered the same difficulties I did when trying to balance stability, feedback, and effectiveness.

However, I was browsing Tindie, as one does, and I happened across a promising breakout board built by Fyber Labs. The driver chip it exposes is not designed for electrovibration, but its application parameters were similar enough for it to be worth a shot. There was a high upside to it working, since the chip itself does a good deal of the work in a significantly smaller package.

After hooking it up, it’s clear: the electrovibration sensation is there. You can run your finger across an insulated electrode and feel the unmistakable stick-and-slip of the phenomenon. In fact, at some settings you can feel a little too much, and I suspect the dielectric is actually conducting slightly. More research, especially into various dielectric coatings and electrode materials, will be necessary before this is a solved problem, but it’s nice to move on from a blocking problem space to an under-explored one ;-)

It is also a bit disheartening, mostly in selfish ways. My original WEFT board was the result of many, many hours just brute-forcing my way to understanding; I have an attachment to the board, imperfect though it is, because it’s more original than most of my work. My work generally involves some clever bricolage, and little originality (in my opinion)—it was cool to have actually reverse-engineered the circuit from the awesome-but-vague Disney Research papers that formed the genesis of my interest in the phenomenon.

But! There’s plenty of work to do. The library currently supporting the chip is pretty bare-bones, and I am taking that opportunity to build out a more complete library that includes some electrovibration-specific methods. There’s also the Hackaday Workshop to prepare for, which means I’ll need to spin up 10 new boards that incorporate the new IC. To make sure I deliver my customers a durable kit in limited time, those boards will likely be motherboards with Fyber Labs’ breakout board riding on it. The board after the Workshop will be a wholly-new, low-profile board that might be available on Kickstarter.

If you’re interested in any of this, could you please drop me a line? I’m noah@weft.rocks, and I have questions for you about what you want in a WEFT board, and what projects you’d like to use it in…