I am dealing with some three-way light switches that people are always forgetting to turn off.
Any suggestions/schematics for making a simple LED indicator at each switch to indicate if the circuit is on or off, which doesn't require an extra wire for the indicator? (The wiring is already installed and covered, so adding wires is not feasible.)
I would prefer mains-powered solutions (no batteries).
Update: Here's how it's currently wired. We use 14/3 with ground (4 conductors in the cable, not allowed to use the earth ground as a neutral). In the US we're required to have a neutral in all switch boxes, and are required to break the hot wire with all switches.
simulate this circuit – Schematic created using CircuitLab
These circuits are switching 120VAC 60HZ USA electrical mains.
Thank you!