Need ideas for simple motion sensor


Joined Sep 26, 2009
Has anyone tried to couple the PIR with something that can send a signal to a remote receiver? For alarm purposes. This would make 1/2 of what I have in mind. Think of a car driving up your driveway (or a deer in the garden...), and you get an audible notification in the house. Perhaps my actual question has more to do with radio than the detection aspect! The area I'm looking to cover is too far away to run wires (plus, that's messy...).
You should be able to use the circuit in the above post to close a contact on a remote control module (by connecting some leads to a button on the transmitter so the relay acts as a button press), you can also try to make your own modules or purchase some premade ones from reynolds electronics ( You will also most likely have to use decoders/encoder IC, they have some 4 bit ones available (I think those are the smalles ones they have), atleast with those, you can incorporate 3 other sensors to transmit data.....

And I would use the Linx Technologies RF Modules (434 Mhz) >> better range,

I have built several of these circuits my self a lot cheaper than you can purchase them from anywhere, Digikey has all the parts you would need (RF Tx/Rx IC's and 1/4 Whip antennas)....

I will have to dig up my Seismic Deer Detector circuit I built years ago that I used to detect deer with in my garden, that can be used in conjunction with the PIR sensor...
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Thread Starter


Joined Feb 4, 2005
Sweet, BMorse, I'd love to have a look if they make an appearance. Those PIR's look really neat; I checked 'em out online - didn't realize they're quite common and people have many hacks for them. I probably have one on the motion-sensing light right out front! For short-term use, I suppose I could rig up something with 22 ga. magnet wire to send the signal out to the house, until I get project-obsessed enough to try to assemble a radio gadget!
Glad I don't have to try to align a beam and collimator now ;o)