Photodiode detection using Comparator not working

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Anonymous
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Hi,

I am new to PSOC

I am using PSOC 5LP with PSoC Programmer 4.2

I have a photodiode & resistor are connected externally, using Vdd and GND(Vss) pins on board as shown in picture.

This should be able to detect obstacle on photodiode and indicate it through the on board LED.

pastedImage_0.png

By default the LED is ON after programming.

What can be corrected in this setup?

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Vasanth
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250 sign-ins 500 solutions authored First question asked

Dear Ajeya,

You may have to modify your circuitry. The photodiode will have a dark current passing through it even at complete darkness. So at any point of time your comparator +ve terminal is not going to have a voltage less than -ve terminal for the circuit to work. You can use another potential divide(or a pot to adjust sensitivity) in one of the terminals while the photo diode-resistor divider is connected in the other terminal.

pastedImage_0.png

Best Regards,
VRS

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