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IR Blocking Detection Circuit

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dragone

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Hi All,

Anybody where can I find the circuitry diagram for IR blocking detection.
The circuit is for detection of a near object (e.g. hand).
I saw some circuit will use a MCU and one 4069.
Pls help me if you know where I can get it.

Regards,
 

ME

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Many systems for detecting nearby objects doesn't use IR blocking detection but IR reflection detection. The advantage of the IR reflection system is that you can place the IR transmitter and IR receiver in the same spot. If you use IR blocking detection you have to place the receiver on the other side of the object you need to detect.
Bang & Olufsen uses IR reflection to open the glass doors on BeoSound 3000 / 3200: https://www.bang-olufsen.com/sw599.asp
 

flatulent

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some pointers

Here are some pointers for your design. Use detectors with IR filters on them. This is a commmon feature. It reduces the false signals generated by room lighting. Use pulse drive above the audio band on the emitter so that room light does not affect your receiver circuit which should be AC coupled.
 

dragone

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ME said:
Many systems for detecting nearby objects doesn't use IR blocking detection but IR reflection detection. The advantage of the IR reflection system is that you can place the IR transmitter and IR receiver in the same spot. If you use IR blocking detection you have to place the receiver on the other side of the object you need to detect.
Bang & Olufsen uses IR reflection to open the glass doors on BeoSound 3000 / 3200: https://www.bang-olufsen.com/sw599.asp

Yes, I'm looking for reflective detection circuitry.
 

mr_ghz

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Hi dragone,

one additional point to flatulent's advices: if you integrate several pulses
you can increase your sensitivity drastical. This is because the noise will
cancel out (it's a stochastical signal) and the amplitude of the signal will
rise. The detection-time will be slower, but with a high repetition rate this
can be corrected.

Bye
 

bobcat1

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Use IS471S IR proximity detector chip

Use IS471S IR proximity detector chip !!

This lowcost chip avaliable from futuare electronics use to detect

the END OF PAPER in printer


LINK to DS: www.acroname.com/robotics/parts/is471f.pdf

cost is around 3$ in 100's

best

Bobi
 

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