Peter "Bobricius" Misenko's Self-Charging LED Necklace Is the "Ultimate Useless Gadget"
Energy-harvesting three-component gadget uses a through-hole LED as both a power and light source.
Maker Peter "Bobricius" Misenko has released what he claims could be the "ultimate useless gadget" — a self-charging LED necklace.
"This delightfully pointless little pendant is the perfect conversation starter and nerdy accessory. An LED that charges itself using light, stores energy in a tiny capacitor, then flashes when you press the button," Misenko explains of the compact board, with only three core components. "It's absolutely, gloriously useless — and that's exactly why you need it!"
Misenko's creation is made up of a compact PCB hosting a through-hole LED, a tactile push-button momentary switch, and a capacitor. You may note that nowhere in the limited bill of materials is anything approaching a solar panel — because the LED itself acts as both a light source and a light sink, harvesting ambient light and converting it to electrical energy to be stored in the capacitor.
There's a reason that the ability for an LED to generate electricity from light isn't commonly used as an energy source: they're capable of doing so, but they're not exactly efficient at it. Misenko estimates it takes around ten seconds to a minute for the LED to harvest enough energy to briefly flash at the push of the button, depending on ambient light levels.
"Warning," Misenko jokes of the device. "May cause excessive explanations about how LEDs can work backwards. Side effects include feeling like a wizard every time you press the button and becoming instantly more interesting at parties. Embrace the uselessness. Wear your science today!"
The Self-Charging LED is available on Misenko's Tindie store now, at $8.98.