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InfaRed (IR) Motion Sensor Answered

So...If I buy an IR Emitter LED and an IR Receiver LED ...and put them face to face...and get power to each of them....Can I somehow create a motion sensor out of that? For example, if someone walked between the 2 LEDs, it would trigger lights to go on. Is that possible?


Wow, that circuit seems ridiculously over my head. :) O well, I'll have to come up with a better motion sensor i suppose. Thanks!

Search this site and you can usually find several other circuits (you could also spend hours there when you see other ideas that snag your interest :P ).

well there was a small platform supported on four rubber buds and the switch in centre underneath the platform.. (my kids call it a board...I call it a platform). weight of cat does the rest and opens his cat dish..but the mice our house was plagued by are too light to open it and let them eat or crap on our cats dinner

Cool, sounds like I'm definitely going to do that. Thanks.

glad you think so.... I made one using a stand on light switch from a lamp....It works fine..except for an ominous clunk as the switch is depressed

So....did you just make ... a large platform (which you can step on) which, when depressed, hits the switch that turned on the light? Right?

ok i im a low tech kinda guy..What about a pressure pad..Easy rig and hardly any electronics..What do ya think

Where could I buy a pressure pad?? Or are you saying simply make a pad, with a button inside of it? Hey...thats not a bad idea at all...just have a button built into the pad that turned a circuit on or off...Genius and WAY MORE SIMPLE!! THANKS MAN!

. That's almost their raison d'etre. For short distances, you can use the pair from an old ball mouse.
. Instead of going to all the trouble of modulating the beam (as per W'burg), just mount them in tubes to narrow their field of view.

W'burg--I like that. It's nice and gets the idea across.

i like the tubes idea - never thought of that.


10 years ago

Can anyone else help me with this?

I tried to make a motion sensor for halloween like this and it didn't work, just sharing my expierence, but you might be able to do it since it's for a different application

You might need to have the IR LED blink at some rate (like your TV remote) so that the receiver knows the difference between it and normal IR light, then you'd need some sort of controller to recognize that no more IR light means to turn on the lights. Certainly possible though.

Ok, so i make the emitter blink using say...a 555. Then you said i need some sort of "controller." What exactly do you mean by a controller? Furthermore, I am a bit of a beginner, so please be specific! Thanks!