Project start: Movement alarm for bag theft prevention

So one of my new projects is to create a movement alarm for preventing bag theft.

The motivation for creating this is threefold:

1) When I go to a happy-hour or a cocktail party, I often have my computer bag with me. But I do not want to carry it around with me, so I put it down somewhere, hoping that no one takes it. I may check on it periodically, or strategically stand in an area so that my bag is in view, but not on my shoulder. I would love to have a small, portable box that I could carry on a daily basis, that will help reduce that anxiety by being an alarm if my bag is taken.

2) My parents just went on a trip through South America, and while they were there they unfortunately had their bag stolen while they slept on a bus.  I felt horrible for my mother, who had taken a bunch of pictures that were on the camera that was in the bag when it was stolen.  I would like to make them a Christmas gift that they can take on their future travels.

3) There is an ‘everyday carry’ contest going on right now at, and I would like to create something to enter that contest.  The rules of the contest are simple: must fit in a pocket, be battery powered, use a Trinket Pro, and be documented on Hackaday.  I will be tracking the project development both here as well as on the project page on

I would like to have it battery operated, but without an on/off switch, otherwise the potential thief could just hit the off button. As a result, I will have an ‘arm’ button, and then you have say 20 second to but the bag + device stationary. After being armed, if the bag/device is moved it would sound an alarm (noise at minimum, and possibly LEDs but that is secondary) until the correct code is entered (I am thinking 4 button / digit code). Could also have a threshold: eg. only if moved for 5+ seconds.

Time to build!


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