[Solved / Archived] VIN precision for low voltage

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Last Post by uugear 5 months ago

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marcot77

(@marcot77)

Posts: 8

Active Member

Topic starter

I need to monitor the cell of my battery and I would like to use the VIN in P2. The cells I’m using divides the voltage by 2 giving me back a monitor voltage around 1.6V max. What level of precision I can expect from the Witty Pi 4 mini VIN? Is there a way to improve the precision in reading voltages that are in a range that spans between 1 and 2volts?

thanks

Posted : 15/06/2024 3:20 pm

uugear

(@admin)

Posts: 479

Member Admin

There is a 57:1 voltage divider between the VIN pin and the 10-bit ADC, and Witty Pi's firmware uses 1.1V as internal voltage standard. So the VIN pin can measure up to 62.7V and its resolution is about 0.06V.

Although it can detect 0.06V difference, it doesn't mean its error is lower than that value. You may calibrate the result by properly setting the Vin adjustment value (search "Vin adjustment" in the user manual).

Posted : 17/06/2024 12:37 pm