ADC reading Calibration

Robotics and electronics discussion Software and microcontrollers
1

Hi all
I am working on a balancing robot, I am using Pololu Dual Motor driver MC33926. on the board there is an out pin FB which sense the current form the motor and gives 525mv/A (according to the data sheet).
My Question is how can i convert this reading to a number in miliAmpere. I am using 12 bit ADC and the reference voltage for the ADC is 3v. besides there is 15k resistor connected in series with the input of ADC.
i know this basic formula
Volatge of ADC=(Vin/Vref)*4096 to know the out put of the ADC but what i want is to know how to convert the ADC reading to Motor current.

Thanks
Eyob

2

Hello, Eyob.

The voltages you read from the ADC can be divided by the voltage to current ratio (525mV/A) to get the current. For example, if you read 787.5 mV, you can divide it by 525mV/A, and you will get 1.5A.

- Jeremy

3

Thank you Jermy, now it works and i manged to balance my two wheel robot, now i am working to improve it more and try to trace a line or a path…
thanks again