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IR sensor not working

February 5, 2012

Based on design from internet i redraw circuit and changing few elements. I just cant get IR sensor to work. IR sensing part is just based on reversed IR diode. It should basicly just sens the beam interrupted or reflected. ( I even tried putting diodes facing each other)

I took some measurments and the reciver IR diode is not letting any current trought it (0V  0mA). I also tried to put reflective surface above and same result. Can sombody figure out what is missing here?

(I checked IR diodes and both are working normaly if not in circuit, Transmitter diode is working non stop)

Here is picture of left part of the board (transmitter)

R1 = 47Ohm
R2 = 220Ohm
R3 = 3.3kOhm
C1 = 0.1uF

This is right part of the board(reciver)

R1 = 1kOhm
R2 = 1kOhm
R3 =  4.7kOhm
R4 =  1kOhm
R5 =  33kOhm
R6 =  22kOhm
R7 = 4.7kOhm
C1 = 0.1uF
C2 = 47uF

Here is picture of evrything on breadboard (yea its crowded its the small one all i got so far)

Picture of scope measurments. Bare in mind that A and B chanel have different values seted:

CH.A: 10mV/Dev
CH.B: 100mV/Dev
Time per Division: 50uS

  1. Keep it simple permalink

    Try to replace the transmitter ir-diode with a normal led- diode. If your transmitter circuit is ok, than the led must be lightning up 😉

  2. nny permalink

    hye… i just want to ask something about this circuit.. can u help me,,,??? how to connect the transmitter n receiver to combination of circuit if the diagram of circuit at gnd??? ..hope u can help me.. :).. thanx.. sorry my english so bad…

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