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Hello, I'm currently completing a project for my uni course and am struggling. I'm trying to use photodiodes to detect and IDENTIFY light sources - basically I need to design a system that can output what the light source is e.g. sunlight, artificial light, torch, candle light etc. I will use the output from an Op-Amp to feed into a processor which will output to a display (7-segment) showing what the light source is. I have a very rudimentary circuit I am using which involves using photodiodes connected to Op-Amps to amplify any current that passes through them. I'm struggling with there being enough difference between different light sources to successfully identify what the light source is. Measuring the voltage coming out from the various Op-Amps just shows the resistor being being used to provide the gain is what's causing results to differ from the next. I've tried using various different types of photodiodes too but they just provide a voltage regardless of what the light source is too. Is there anything anyone knows that could help me in any way? Much appreciated.