Electronics > Beginners

motion activated led without use of microcontroller

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dennisyuki:
I wanted to build a motion actived LED light bar.   Project specs are that when some on walks by the light bar the LEDs will light up and stay on for 20 secs, then shut off.   I would like to build it without the use of a microcontroller.   Is this a simple circut to build without a microcontroller.   I searched google, but I cannot find a circuit that would work.  maybe I am not using the right search words.

Your help is appreciated.

Rerouter:
you want to detect motion or more importantly presence? if presence you could use an infrared tranciever with a very high gain, this would generate a large signal whenever something increases the reflected beam, e.g. a person, this then gets fed into an op amp peak detector, and use that buffered peak to switch on or off your leds,

PA0PBZ:
Get yourself a PIR (Passive InfraRed sensor). They are very cheap, all you have to do is extend the active time to 20 seconds, either in the device itself or something external like a 555.

EEVblog:
Is this a bargraph? or just a single LED strip that goes on/off?

Paul Price:
Here attached is a most elegant solution I created quite a few years ago, modified for this golden age.

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