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ADC stuck on high reading

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ADC stuck on high reading

By uncleSax
-  Mon Jul 06, 2015 1:29 am #183183
I've wired my adc module to a battery pack and I was trying to read a pressure sensor made of velostat.
But even is the VDD cable is not connected to the sensor, I keep reding the maximum value 2047 ( I'm using the reference voltage +- 2048).

I'm pretty sure the everything is wired up correctly. What could it be? IS the ADC module broken?

Re: ADC stuck on high reading

By uChip
-  Mon Jul 06, 2015 8:23 am #183188
It is certainly possible that the ADC is damaged, but it is also possible that the unpowered sensor has a high impedance and the ADC input circuit floats up. Without seeing your entire circuit it's impossible to say.

Some things to try: Did the ADC ever give a reading other than 2047? If so, under what conditions? Can you try those conditions again? Can you try reading the wiper on a pot? Have you tried grounding the ADC input?

Good luck,
- Chip
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