Attempting to set vRef on DRV8825 with Arduino Uno R3 using screw driver method to 0.9V, but it's reading high voltage around 4.2V?
Using a few tutorials off youtube I have tried using both external power 12V, 3A as well as the standard 5V from Arduino since my stepper motor is not attached.
When I go to adjust the DRV8825 potentiometer to adjust the vref (for Nemo 17 = 2.0A, so Vref = 2.0/2 - 10% = 0.9V) 0.9 is what I'm trying to achieve but when I place the screwdriver on it's around 4.2V. Tried turning screw and not much different so I'm guessing something else is not correct.
See attached image
Total understand.
Issue is just setting the vref only and I tried using the external power supply as I mentioned 12V, 3A connected as well as the other option of using the 5V from Arduino since the Stepper Motor is not connected and I'm just setting the Vref. Both provide high V (around 4.2V) at the screw when trying to adjust vref to the desired 0.9V.
Below is an image using the external power source.
My question is what would be causing these high V readings at the screw (faulty driver boards, faulty wiring, faulty capacitor, user error etc)
I was able to resolve the issue.
Poor Connection to Breadboard
The breadboard doesn't offer great connections, so I tried to connect wires directly to the DRV8825 board and this solved my issue. I could now get proper readings off the screw at my 0.9V setting.
I was able to hook the rest up and drive the NEMA 17 2.5A stepper motor without any issues.
What does the datasheet of the DRV8825 say about minimum motor supply voltage? I would be surpriced if 5 volt is enough.
That indicates something is wrong.
Using breadboards for motor currents is not good. The BB might get damaged by such currents.
