The idea of a lightning detector crossed my mind as I was thinking about building a weather station (https://www.thingiverse.com/thing:2849562). There’s at least one pretty good quality complete chip for doing so that seems to run between $25 and $35, but I did also find a couple of DIY sensors that look promising.
- http://rienquepourlesyeux.free.fr/Detecteur%20de%20foudre/Lightning%20detector.htm#
- Have most of the parts to build this (with a couple of substitutions), ordered the op amp and would still need a pot
- https://www.electroschematics.com/1021/lightning-detector/
- Ran across this one first, which linked to the other in the comments. Didn’t have BC109C’s, but looked up a couple of 2N3904’s to see if I can get this built as well.