0.9.0 - pressing the power button from a browser
A KVM that can see a hung machine but not restart it is half a tool. This release adds the other half, with no custom hardware: a PC817 two-channel optocoupler module on each side does the whole job.
The device can now press the target's front-panel power and reset buttons, and read its power LED back the same way. Optocouplers mean there is no electrical connection between the two machines - light crosses the gap, nothing else.
The console gets a Power panel that drives it, and asks before doing anything destructive. There are three actions: a click of the power button, a five second hold for a hard off, and a reset.
Everything about the wiring is a setting rather than a build: which GPIO pins you used, how long a pulse should be, and which way round the module triggers. So the same firmware runs on a board with nothing wired at all - it simply says the feature is unavailable and why - and guessing a module's polarity wrong is a checkbox, not a reflash.
The wiring guide is in docs/wiring.md.