Clarification for IR sensors

I am learning how to work with the X-Y IR sensor and I have a neophyte question. I power the IR sensors from the receiver, with Vout~5V from the BEC. The same source powers ardupilot (I guess it is denoted Vcc in the schematic, assuming that no external battery is connected). So Aref=Vcc=Vout right? Then, I am correct in assuming that when the IR sensors are level, the output is Vout/2, and when read from an analog pin the pin reads 511 at level? Or does the IR board regulates the input V to its own 5V? The reason I am asking, is that if the IR board references to an internal (fixed) voltage, then a bias is introduced in one of the attitude signals, unless Aref is set to the same voltage.

I would assume that the IR references to Vout, and since Aref=Vout fluctuations in Vout only affect marginally the resolution, but not the centering of the sensor. I am wrong?

Thank you
Alberto

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Alberto June 25, 2010 at 3:28am

Thank you. If the FMA are put together as the Paparazzi, a voltage divider supplies Vout/2 to one leg of the OpAmp. So at zero angle the sensor reads Vout/2. That makes sense.
3D Robotics

Chris Anderson June 24, 2010 at 7:26pm

All necessary theory and specs are here.

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Clarification for IR sensors

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