Detect Electronics

For the duration, you sense the presence of electronics within 30 feet of you. If you sense electronics in this way, you can use your action to see a faint aura around any visible creature or object in the area that is mechanical in nature, and you learn the field of technology it is based in, if any.

The spell can penetrate most barriers, but it is blocked by 1 foot of stone, 1 inch of biological life, or 3 feet of dirt.