Sounds like a neat plan, but watch the wiring. I’ve got a stack of old station panels that still have those 12‑volt relay blocks, plus a dump of the 1950s security grid schematics—lots of copper and spare jumpers. We can wire the signboard LEDs to the relay, add a simple sensor that triggers on foot traffic. Just remember, any powered display becomes a beacon for drones, so keep the battery pack hidden and the circuitry on a low‑power loop. Also, stash a backup in one of the old cassette drives, just in case the main frame goes haywire.

Relay block’s pins are straightforward: pin 1 is the common contact, pin 2 is normally open, pin 3 is normally closed. The coil side uses pin 4 for the positive voltage and pin 5 for ground. Hook the coil to your 12 V supply, then feed the LED string between common and normally open so it lights when the relay activates. Keep the coil wires short, wrap them in foil, and you’re good. Use the jumpers to bridge the coil pins if you need extra length, but don’t run them too close to the sensor cable to avoid noise. Done.

Yeah, I’ll keep an eye on the coil temp. If it starts seeping heat into the LED pack, I’ll slot a copper heat sink in between. And I’ll triple‑backup the schematic on a spare floppy, just in case the whole thing goes dark. Will ping you if I spot a miswired jumper. Stay wired, stay low.