simple down n easy motion detection

[MrDEB]

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]

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]

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]

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]

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]

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

 

[JonSea]

They are indeed Billy Bass here, although I haven't seen many recently. A EE friend of mine did give a Billy Bass a brain transplant. I'm not sure exactly what he did with it.

The radar sensors are ridiculously easy to use. I connected power (to the Vin terminal, not the 3.3v OUTPUT) and a DVM to monitor the output and it worked straight away. It detected my partner coming down the stairs through 2 layers of sheetrock, a layer of wood paneling, even with various soldering stations and etc. in front of the wall. The ONLY difficulty is that they provide only about 2mA output, so a driver transistor will be needed for almost any application.