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IR receiver and output over short distance Answered

  I want to set up a short distant IR sensor(<1"). I just want it to register when something is between the two items. Its a pretty simple circuit I just have no experience with optical receivers. Any help would be greatly appreciated, thanks



6 years ago

You should just need an IR LED and an IR phototransistor for such a short distance.

If you are just wanting to detect when the beam is obstructed or not, connect the collector to positive voltage (say 5V) through a 10 k resistor. Now, when the IR LED is driven on and it shines on the phototransistor, the transistor will turn on and the collector will be pulled low, almost to ground. If the beam is interupted, then the transistor will turn off and the collector will be pulled up to positive voltage. The voltage on the collector of the transistor can be used to drive other logic to interface to whatever circuitry you have in mind.