Motion detector ic ?

[bouvett]

HI,
i am designing a circuit which alerts people when something moves.. say a box is displaced. now i once saw somewhere on the internet that there exists some piezo electric device which is suitable for this.... any one knows of it and has some links? other methods of doing this are also appreciated though things like an infrared make or break technique is not really preferable...

thanks a lot for your help
regards

 

[KMoffett]

Google: ultrasonic motion detector

Ken

 

[georgetwo]

hay
what about placing a highly sensitive momentery switch that triggers when whatever object or load been placed on it is removed. you can link a million together. to make every thing hidden, use tiny copper wires for small transformer.

 

[audioguru]

Ultrasonic is not used for a burglar alarm motion detector. Infrared is used.
Look in Google at PIR Motion Detector.
But infrared will not detect a dead box that is moved, just a warm mammal.

 

[Nigel Goodwin]

Ultrasonic is not used for a burglar alarm motion detector.

It used to be though, but now it's PIR's.

 

[gerty]

Actually they're both used in the same device, it's called Dual Technology. Both types must be tripped at the same time to put the detector into alarm.Supposed to cut way down on false alarms.
Microwave is also used, but it has the bad habit of looking through walls, wooden doors, etc, all of which mean false alarms.

 

[bouvett]

no its more like for a mountain bike type of alarm... i just wanted to avoid any wires as much as i can you know?


thanks

 

[MrDEB]

A bike alarm?

go with a tilt switch
anyone move your bike BAM the alarm sounds

 

[EN0]

I was going to build a project that involved a tilt switch, but could never find the one I needed. It consisted of mercury and was obsolete due to RoHS restrictions. I know that NKK Switches has a few new ones and you might be able to use those if you'd like to even use a tilt switch.

 

[astronomerroyal]

Consider browsing the sensors at SparkFun

SparkFun Electronics - Sensors

as for tilt switches I bought some quite good non-mercury ones at a surplus store; electronic goldmine or allelectronics.