MAKE subscriber Rob Miles of Tacoma, WA, made a cootie detector for his kids out of an ATtiny45 with a paper clip for the biometric sensor.

Kids love games of exclusion. “You’re a zombie!”, “You’ve got cooties!”, “You can’t come in my room because….”. I must hear this 500 times a week around the house. Well, after some exhausting research we have discovered that zombification and cooties have a similar galvanometric effect on the victim’s skin. Sooo….

This device will provide the following feedback depending on your skin’s resistance:
“CLEAR” = Green light after test sequence.
“INFECTED” = Red flashing light and then solid red after test sequence.
“DEVICE TAMPERED” = Alternating red and green lights (as seen when I shorted it with the screwdriver).