Possible bug in SimpleFOCShield v3_2024-06-23

[Antun_Skuric]

@runger

IMHO that significantly complicates things, as then the output would be ratiometric around 5V/2… this would not be in the middle of the 3.3V MCUs ADC range, so then you’d have to down-shift the current sense signals, but only for the 3.3V MCUs

In my experience reagardless of supplying 3.3V or 5V to these sensors, they are centered around 2.5V (even if using 3.3v).
So you still lose some current measuring capacity, but not much really.
At 3.3V you can measure ± 4.32Amps and on 5V ±5Amps

Does the SimpleFOCShield v3.x actually support 3.3v MCUs?

Hi @Jeremiah_Rose , You are abosolutely right! The ACS712 does not support 3.3V, at least in their datasheets. However, in my tests I was able to run them consistently at 3.3V without any issues. Also if you use them at 5V rather than on 3.3V. The gain is 0.185 V/Amp and the range of 5Amps would give you the voltage range: [ 2.5 - 5\times0.185,\quad 2.5 + 5\times0.185 ] = [ 1.575,\quad 3.425] So it would be just shy outside the range of the 3.3V adc input. The max current you co…