IR object sensor design

[otuzsubat]

Hi. i need an Ir object sensor. For this i designed receiver and transmitter circuits. Transmitter circuit will produce continuous Ir pulses. When an object comes in front of sensor, it will reflect IR light to the receiver. When receiver detect Ir signal, its output will be low (logic 0). I will connect the output of receiver to microcontroller.

My problem is, when i put an object in front of sensor. The output of the receiver is not stable. I obtain a square wave. I want to obtain a continuous low level signal for microcontroller. How can i do this? Do you have any suggestion?
Best regards

Transmitter

**broken link removed**


Receiver
**broken link removed**

 

[PaulHolland]

Hi, What is the frequency of your square wave ?. What you can do is make a PLL with an NE567 chip that is tuned to this squarewave frequency and if you put the output IR signal into the NE567 input you will get a stable and nice signal on pin 8 ONLY when there is a sqware wave frequency on the input of the sensor due to reflection. NO Microcontroller is needed this way.

 

[Abhishek K]

you can directly use a IR Tx-Rx pair...no 555 req in that case...power req might change thoug. but thats a lot more easier.. and works fine