3 ms·
How does the light bulb know it's unscrewed? How is that different from turning the switch off? it could easily measure this by either: - a limit switch, or
by DoctorOetker 7y ago
How does the light bulb know it's unscrewed? How is that different from turning the switch off?
it could easily measure this by either:
- a limit switch, or
- a split center electrode: if there is a conducting path between left and right halves between center electrode, then the bulb is screwed in, or
- measuring the capacitance between outer and center electrode: in open air there is the known capacitance, when screwed in both the electrodes of the housing, and the long parallel conductors going to the switches will alter the capacitance
- myriad other ways: electrically there is a huge difference between an unscrewed bulb, and a screwd-in bulb in an open circuit
- StavrosK 7y agoHow does it do all this with no power?
- DoctorOetker 7y agoa capacitor to power the microcontroller for a few milliseconds? actually, if the goal is to detect a reset operation by unscrewing: while unscrewing and shortly after the circuit is open, the previously contacting electrodes are still close by, such that it can be powered capacitively while it realizes it is being reset... this is probably noticable by measuring the change in complex impedance
- StavrosK 7y agoYour solution is to make laypeople unscrew the bulb with the socket still live, while increasing the cost of each bulb by a lot?