A homemade alarm system made from two “normally closed” audio jacks is the focus of our most recent Weekend Project, the Alarm Bag. The alarm system, built into an enclosure (above), can be installed into any bag (in our project, a messenger bag is used) or even modified to act as a door or window alarm. The 2-jack design means the alarm will activate whenever the second audio jack (the trigger) is removed. It’s an interesting use of components not typically designed for this purpose, except for the 102dB Piezo siren which is an absolute screecher of an alarm!

See all of the RadioShack Weekend Projects posts (to date)

Nick Normal

Nick Normal

I’m an artist & maker. A lifelong biblioholic, and advocate for all-things geekathon. Home is Long Island City, Queens, which I consider the greatest place on Earth. 5-year former Resident of Flux Factory, co-organizer for World Maker Faire (NYC), and blogger all over the net. Howdy!

  • http://autofolks.wordpress.com/ autofolks

    That was a wonderful experiment. 

  • http://www.facebook.com/profile.php?id=611449350 Robert Neulreich

    This looks like just the type of thing I have been looking for. I plan on adapting it into an ammo can and installing in my Jeep for low end theft alarm.