Can anyone point me at some circuits showing how to connect an IR photodiode (note a 2-pin photodiode not one of those fancy "photodiode plus decoding circuitry" 3-pin sensors) to the ESP32's RMT circuitry?
I'm guessing something that boosts the photodiode's output is required - opamp? transistor?
I would prefer to use the ESP32's won RMT decoding, otherwise what's the point of having it .
Thanks.
Connect IR photodiode to ESP32 RMT?
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Re: Connect IR photodiode to ESP32 RMT?
That's kinda hard. The decoding circuitry is there to make those chips specifically sensitive to a 38KHz carrier, ignoring everything else, and that is why they can give such a good binary output. A photo diode does not filter a carrier wave, so it picks up everything and everything goes in the analog output value it gives. Sunlight on photo diode? That's a DC bias in the output. 50 or 100Hz from an incandescent lightbulb? That's a 50 or 100Hz sine in your output. Got something that uses IR light like an Apple phone or a VR lighthouse? That ends up in the output. If you simply threshold that to get a binary value, you'll get an undecodable mess, with all of those influences jumbled together rather than a simple binary stream you can feed into the RMT.
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