Ambient-light-ignoring-sensor


Posted on Jan 7, 2013

A resonance-tuned narrow-band amplifier reduces this optical object detector`s sensitivity to stray light. C1 and L1 in IC2A`s feedback loop cause tbe op amp to pass only those frequencies at or near the LED`s 5-kHz modulation rate.


Ambient-light-ignoring-sensor
Click here to download the full size of the above Circuit.

IC2B"s output increases when the received signal is sufficient to drop the negative voltage across C2 below the reference set by R2.




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