Comment by ErroneousBosh

> Pressure switches, flow sensors, mechanical flame detectors, power supply monitoring, watchdog timers, and XX years of Honeywell or whoever knowing what they are doing.

Nope, nothing as complicated as that. You're close with the watchdog timer.

The solenoid is driven by a charge pump, which is capacitively coupled to the output of the controller. The controller toggles the gas grant output on and off a couple of times a second, and it doesn't matter if it sticks high or low - if there's no pulses the charge pump with "go flat" after about a second and drop the solenoid out.

Do the same thing. If a sensor at the edge of the LIDAR's scan misses a scan, kill the beam.

Same way we used to do for electron beam scanning.