1 / 32
Anglerfish LED costume stick
I built a simple LED costume piece, an anglerfish style lure on a stick, deliberately limited to nothing more than an LED, a battery and a resistor, with the battery hidden under tape on my skull and about 30cm of wire running up and back. I had wanted the LEDs to light up when two of us got close to each other, but there was no time to work that out before the event.
Description
I made an anglerfish style LED piece worn on a stick, with about 30cm of wire running each way and the battery hidden on my skull under the tape. I set myself a limit of just an LED and a battery, and a resistor, so there is no microcontroller in it.
The thing I wanted and did not manage was for the LEDs to light up when we got close to each other. There simply was no time for it. Stavros suggested putting a photodiode in each, blinking them and measuring the time between voltage spikes, then lighting up if the timing matches the other LED, and he wondered whether the LED itself could be read as a photodiode while still being driven as an LED. That would need an MCU, which is outside the limit I set, but I want to try it next time.
My worry with it is interference. With 30cm of wire going both ways carrying charge, I think the stick picks up the electric field and the capacitance gets affected, so it may be hard to tell the other person's LED from ambient light. It is not about waves but about charge. Putting the LED closer to the MCU might just work.