Light This PCB Candle with an Actual Flame

LEDs can reasonably approximate candles in situations where you need light, but don’t want to risk burning your house or restaurant down. On the other hand, they can’t quite take the place of the real thing, and of course you don’t get the fun of lighting them on fire with a match or gas lighter. At least that’s normally the case.

Miroslav Hancar has come up with a PCB alternative featuring RGB LEDs that can be lit by holding a flame up to them. While details of how this works are somewhat slim, the activation method would seem related to how LEDs can act as photodetectors as well as light emitters.

So yes, you literally burn the LEDs to get this electronic device to start, and Hancar reports that “they can survive hundreds, if not thousands of ignitions.” He does note, however, that you shouldn’t expose them to high temperatures for too long. The unit can be powered over USB, and includes charging hardware for a 3.7V battery. There's also a button used to check the charge state via LEDs and turn the candle off.

If you need to see it to believe it, Hancar lights a series of through-hole candles in the first video below, an SMD version in the second, and one can be seen diffused in a holder in the third clip.