I'm curious if anyone has built one of these before? It is a radiation detector based on an BC517 NPN Darlington transistor. The way I'm seeing it is the radiation excites the leg and allows voltage.
It also shows the "Dave" effect where she stands up and the meter jumps.
One of the comments to the video says since the transistor can handle more voltage, she could connect two 9v batteries in series to increase the sensitivity.
I'm also wondering about what the signal looks like going into the meter, is it a constant voltage that goes up and down, or with a lot of static where it might be suitable to connect to an amplifier and speaker? It would be interesting to replicate using a scope instead of a DMM.
I guess the next time I make a trip to the parts store I'll pick up some of these transistors and try some different things, maybe even figuring out a way to connect it to an ADC pin on an AVR. I'm not sure yet.
Based on what you've seen, is the BC517 the best for this or would there be another one which might be even more sensitive?