Sean Ragan just put up a tutorial for this simple analog tamper-detecting switch for guarding his garden over on Make: Projects:

This clever mechanical switch remains open so long as it is balanced in an upright position. But disturb it in any way, and the ball falls against the bars of the cage and closes the circuit. Use it to control an alarm to protect your valuables, or to trigger a camera to photograph wildlife.

Becky Stern

Becky Stern

Becky Stern (sternlab.org is a DIY guru and director of wearable electronics at Adafruit. She publishes a new project video every week and hosts a live show on YouTube. Formerly Becky was Senior Video Producer for MAKE. Becky lives in Brooklyn, NY and belongs to art groups Free Art & Technology (“release early, often, and with rap music”) and Madagascar Institute (“fear is never boring”).