I wanted to make a ring that didn’t need batteries, so I looked around the house for lemons, onions, etc, but they weren’t charging the capacitor at ring scale. Our smoke detectors have Americium-241 in them, and I had one to be recycled, so I did the recycling myself. I originally tried a Polonium 210 refill for a Staticmaster Alpha Ionizing Brush (old photographic equipment I had laying around) but it was past date (halflife).
How it works: Alpha particles are released onto the shank of the ring from the alpha source (Americium) charging it with both positive and negative ions. The wearer’s finger acts as a dielectric between the charged plates (ring shank) creating the necessary polarity to charge the electrolytic capacitor and then light the LED.
NOTE: I don’t recommend trying this experiment because my hands broke out into a rash after handling the Americium–but it works!
O.K., now that April is over, many folks have contacted me regarding the safety or the veracity of this Ring-A-Day. This was my April Fools Day Ring based on the true-life story of the Radioactive Boy Scout.