# simple down n easy motion detection

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#### MrDEB

##### Well-Known Member
Have a craft fair in May and presently working on some whirligigs. Two of them are Saquatch and idea came about to put some red leds for eyes.
Well now I am considering a Sasquatch silhouette with red led eyes for a room ornament (not really a night light but a conservation piece)
Thinking a motion sensor that isn't too big. I have several PIR modules but they are kinda big in size so something smaller or even just a photo cell??
Be really cool to have the Sasquatch flap his arms (the whirligigs do this)using a servo motor.

#### Beau Schwabe

##### Active Member
Look at two sensors in a differential mode. ... what this does is mathematically cancel out any common mode signals leaving you with a greater signal to noise ratio. The two sensors can be light, sound, etc.

#### AnalogKid

Ultrasonic proximity sensors on ebay for $2, light sensor modules, etc. ak #### JonSea ##### Well-Known Member Most Helpful Member Try these "radar" sensors. They will detect people at 5 meters (which can be decreased by adding R or C), they will detect people THROUGH walls, they are cheap, small and easy to use. They are about 1" × 2" and will work over a large voltage range. You will need to use a transistor to switch any current. #### dr pepper ##### Well-Known Member Most Helpful Member You can get Pir sensors on ebay the size of a 10mm Led. I've seen cheap plastic ornaments at the pound shop that use a single photo resistor for motion sensing, must just look for a change in light level. #### MrDEB ##### Well-Known Member Delt with stand alone PIR sensors and they can be finicky. The radar sensor sounds interesting as does the ultrasonic sensors. Thanks for suggestions #### large_ghostman ##### Well-Known Member Most Helpful Member Goto the thrift shop and find a couple of billy bass, take apart and use the bits. Are those flappy fish things called billy bass there? might have the name a bit wrong, but essentially its all in and cant cost more than$5

Would save poor old jonsea some stress, but might also deprive the rest of us some giggles. But would do the job