Show-mode build · to scale · 140 mm reactor
The rim LEDs spin up one by one, flicker, then lock blue as the bubbles start. Press Power to replay it.
Brightness and pulse speed follow the current, the way an INA219 sensor on the Pico would drive them.
The blue hydrogen column bubbles twice as fast as the red oxygen one. Turn the current down and both slow.
The screen on the stand shows live Faraday's-law numbers: current, H₂ per minute and total made.