Here is a smart ring light fitted for the LED era. This one is powered by LEDs. This huge contraption was invented by Gvido Mūrnieks who also made a [.
Wedges of an orange generate enough current and electrical juice – volts – to power an LED. The fruit’s citric acid helps electrons flow from galvanized nails to copper wire in this exposure. (Photo by Caleb Charland/National Geographic)
Hacking Photography - one Picture at a time
Long Exposure Pictures with Sparklers (image by Nick Pelletier)