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The Hand Held Maneuvering Unit

Ok I've changed the name of the gemini reader device. I was reading through the Gemini wikipedia articles and found that on the EVA missions they tested several iterations of something called the Hand Held Maneuvering Unit (HHMU). It was a portable gas thruster which fired a gas out of a nozzle to propel the user around. Astronauts found it hard to use as you had to align it with your centre of mass, or it causes you to spin.

My gemini reader will be a handheld unit for maneuvering around Geminispace, so the name fits perfectly. Like the real HHMU, the device will probably be a bit cumbersome to use! The name is also a little clunky but I'll probably mostly refer to it as the HHMU or HMU.

I ordered a Waveshare 3.7 inch monochrome e-paper display plus their ESP32 drive board for it, and a few weeks ago they arrived. So far all I've done is put on a "blink" Arduino sketch to check that the board works and I can program it.

Not sure yet whether it makes more sense to program this in Arduino C++ or Micropython. You can do either of course but I need to check whether the libraries I need are available for either. There are e-paper display drivers for both but I'm not sure about the Gemini communication over WiFi. It'd definitely be easier to program in Python but I'm a little worried about the performance.

Speaking of performance, this display has a stated "full refresh" time of 3 seconds. Not ideal - hopefully you can do a partial refresh of the display. Otherwise my plans for typing on it won't go so well! It's fine for reading but I wouldn't want to enter a URL on a display that's only updating every 3 seconds. At least I wouldn't need to worry about the ESP32 being too slow!

Typing on this thing will be a challenge. I don't want to make a full physical keyboard for it, which I've mentioned before. What I'm trying to figure out is whether you can type with just a clickable scroll wheel. Non-painfully, that is. I've been posting about my experiments on the Fediverse but I'll write them up soon.

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