Some shopping suggestions

 

motion sensing alarm (maybe could be hacked?) - allelectronics.com
glass break sensor - allelectronics.com
flex sensor - jameco.com
force sensor - electronic goldmine
infrared object detector, 8 inch range - electronic goldmine
infrared detector, 30 inch range - acroname
digital compass - imagesco.com
PIR detector - electronic goldmine

 

 

 

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