P.I.R. sensor to detect small birds

I would have thought that a PIR would detect a bird if it was close enough, but maybe feathers are too good as thermal insulation. Perhaps IR beam(s) instead of a PIR?

Or maybe a microwave doppler motion sensor? I once used one of those as a possum detector but then possums are a bit bigger than most birds. Again it would depend on how close they are.

I'm assuming you don't mean emus or cassowaries...

Andy Wood snipped-for-privacy@trap.ozemail.com.au

Laser trip wire sensor or a weight detector or perhaps a touch switch in the form of a perch.

Another thought. Didn't you previously mention using Canon cameras? If CHDK is available for the camera you are using then you could use the motion detection feature provided by CHDK. Andy Wood snipped-for-privacy@trap.ozemail.com.au

"L.A.T."

A microwave ( Doppler) or possibly ultra-sonic movement detector is what you need.

..... Phil

Maybe a CAT sensor tied to a trigger switch.

Tie a cat to the shutter release? (CAT sensor - wtf?)

Pull , ( thrower operating noises) roowwwwshrechhhh (flailing cat) Boom boom ( thats a shoty folks) seems fitting

Check out this link

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Even if you don't get ripped off, that looks like it would be pretty expensive.

The OP seems capable of some serious DIY so perhaps could make something using this:

Andy Wood snipped-for-privacy@trap.ozemail.com.au

The story so far: Thank you all for your responses. I have looked at them all, including the article in Everyday Practical Electronics May 2003 and the module from New Zealand. The remote places I have in mind don't lend themselves to a trip wire or something based on the bird breaking an I.R. beam. I have looked at one or two methods involving a laptop, but I'd rather avoid that added piece of hardware if possible. For the time being I am trying out a cheap PIR motion detector from the cornucopia that is Ebay.

When i enquired a while ago, it sold for $120, you just have to add camera and SD card.

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I have had mixed results. Most big(gish) birds trigger the PIR but many small birds do not. I can't seem to see any pattern as to which little guys set off the PIR and which are ignored. Mrs. tt92 has suggested illuminating the area with an array of I.R.LEDs which might add some reflected IR to the radiated IR of the small birds and thus make them more likely to trigger the PIR. The additional radiation may tun out to be anything from insignificant to really useful. I don't know how to find this out except by trial (and error). Any thoughts? The project has subtly changed from being a hunt for bird pictures to being a technical challenge.

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IR leds operate in the very near IR at only just outside human sight, and some energy also inside this range. The PIR detects wavelengths several to many times this, as this is the range emitted from body warmth. So I would predict that though the target may reflect some of the near IR, the pyroelectric IR film will not be sensitive to this wavelength.

By chance I got hold of a small toy with a really simple motion detector in it, which would probably do this job.

The toy is an Echo Bot from

But the sensor appears to be simply a photodiode mounted at the far end of a 2mm ID black plastic tube. I presume its AC coupled to an amplifier, so that any motion in front of the sensor generates enough change in the light level to trip a comparator. Really simple, but quite effective. Range is around 1m max, but might do what you want. I would not bother buying the gadget, just set up something using say a BPW34 or similar, with a dual opamp to do both amplify and comparator.