Ghost detector

Unexplained cold spots? Feeling of being watched? Could you have misbehaving tech, or ghosts? Let's build a cute little ghost detector you can leave all around you for ambient observance.

First you'll need a simple near-field tester for electromagnetic compatibility. I cut the battery holders off the back and started prodding around the circuit with a multimeter and crocodile clips.

( Explore )

I wanted the unit to be as small and neat as possible so I tried to squeeze everything in behind the LED board.

Wire up circuit into a neat package
Photo by chebe

( Build )

That's it. Now all you need to do is leave it where it will encounter electromagnetic disturbance.