I am working on the receiver part of a Visible Light Communication project. I'm using a TEMT6000 to receive the visible light, then this sensor is connected to a PCB powered by an ATmega328 SMD that will perfrom the demodulation scheme and then this PCB is serially connected to an Arduino to do another task that it is not important now.
My question is related to the PCB design. I want to make it as smaller as possible. I attached the schematics I did so far. What I'm not sure is where to connect the analog signal (SIG) from the phototransistor (The TEMT6000).
Should it be the voltage input from the voltage regulator and then the voltage output should be 5V (voltage I'm working with in the Arduino).
what about the AREF pin from the chip? maybe the SIG should also be connected there?
For your question about the regulator, Since the maximum voltage you can get from the sensor is 5V, the output of the regulator would not be 5V. Regulators need an input voltage that is some amount higher than the output. This difference is called the "dropout voltage". For example, if I am using a 5V regulator with a 1V dropout voltage, the minimum input voltage I can use would 6V. In short, don't connect the sensor to the regulator.
The AREF pin is the AnalogReference voltage that the analog pins compare to, so I wouldn't connect the sensor there either.
