"Signal tracer" driven by UV light

Just an electronics project for me to learn the basics.
This is a darlington array with uv leds as the main signal source and another uv LED feeding into those. this makes a sensitive antenna for listening to electromagnetic radiation. At least this is my understanding. I just stumbled into this when messing with my UV oscillation receiver.
Sorry about the poor sound. It's literally a dollar store earbud scotch taped to my phone's mic.
What you don't hear in this video is you can actually hear the crystall oscillation signal on the thermometer breadboard as you get closer to it on the circuit.
I've also used this to listen to the clock on my coffee maker and oven. kinda cool that you can listen for electronics that have a timing device. It's also "cool" to hear how many electronics components are still on when they're "off"
I also have an infrared LED on this to listen to signals coming from remote controls. Just listening to everything besides sound.
I may take this outside during the solar eclipse to hear the sun come and go (I'll turn off the feeder LED)