Make: Projects – Ball-in-cage alarm switch

Photography & Video Technology
Make: Projects – Ball-in-cage alarm switch


I’ve been looking for an excuse to build one of these clever tamper-detecting switches for a long time. When a mystery critter recently started raiding the fresh catnip I grow outside as a treat for my indoors-only cat, I saw my opportunity. Sure, I could’ve bought or borrowed a commercial trail camera, or hacked a PIR motion detector circuit, or set up an IR webcam with software-level motion detection, but I’ve long been charmed by the simple low-tech design of the ball-in-cage switch. Here’s how I did it.


2 thoughts on “Make: Projects – Ball-in-cage alarm switch

  1. Becky Stern says:

    This is great, but to really capture the full essence of the project, I think it needs a picture of Moonie with her catnip… =]

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I am descended from 5,000 generations of tool-using primates. Also, I went to college and stuff. I am a long-time contributor to MAKE magazine and My work has also appeared in ReadyMade, c't – Magazin für Computertechnik, and The Wall Street Journal.

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