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ADC Resolution Scale

Question asked by Stevo on May 2, 2015
Latest reply on May 2, 2015 by baird.hal.001
Hi All,

I am using the ADC on the STM32F407VGE to detect water through an infrared sensor. 

I am getting a very small change between seeing the water and not. With the sensor clear there is 0.1 volts which reads around 130bits on the conversion and with water it is around 140bits which should be around 0.103 volts.

If I cover the sensor over with my finger I get full range of 4095 which will be 3.3volts, so i know that it works.

There is a possibility that the sensor is still receiving some light from the emitter through the water but I am still getting a change even though it is small.

Is it possible to alter the resolution to be able to make the difference of the 0.1v to 0.103v larger on the ADC converted value?

Is there a possibility to use a look up table to determine the resolution scale?

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