Noise coming from the VNH5019 on the MxPWM line to the Ard


I am using a Dual VNH5019 motor driver shield with an Arduino UNO R3 where the Arduino is powered separately by the Notebook (jumper is off)

The issue: I get some big noise on the pot feedback line ONLY coming from the M1/M2PWM lines (VNH5019) to the Arduino and ONLY if the PSUs (24V) are on.

Second there is something which makes me stunning: the mouse pad of my notebook does not respond respectively there is a big lag on it, ONLY if the PWM line is shared to the Ard and the PSUs are powered on.

To be clear: no 5V line is connected from the VNH to the Ard, ONLY the PWM line is shared.

Thank you.


I could solve the issue myself, it was by accident and coincidently coming from the notebook (had this never before because testing any motor drivers I have never used the power saving respectively the battery mode): if the notebook is running on battery mode, the usb port seems to be jammed, compared with this running on power charging mode no issues have been detected. Sorry for the inconvenience.

Hello, Peter.

I am glad you were able to get your set up working. You should keep in mind that there should be a GND line connected between the Arduino and the VNH5019 to allow the Arduino and the Driver board to agree on what voltage 0V is. Otherwise, the PWM signaling probably will not work. If you do not have a GND connected, it is possible that there is some sort of ground path when both your power supply and laptop are plugged into the mains, but that is not an ideal configuration. If you post pictures that show how your system is connected, I can look for anything that is out of place or missing.

By the way, one potential difference between having your laptop plugged in or not is that your laptop might be able to supply more current to the USB bus when connected to the mains power than when running from its internal battery.


Hello @Nathanb

Thank you for the support. Of course a GND line is shared to both boards normally, my testing purposes was only to pinpoint the issue. Your VNH5019 boards are high quality samples and are working on 24V like a charm. I linked a youtube video where you can see the VNHs in action (not yet finished, this is the first layer of a sway surge table of a racing simulator running at almost half speed)


That looks like a pretty cool project. What software are you using to make the Arduino run PID control?