I have an aruino mega for piloting a motor driver card, using PWM to control the speed and one pin other pin for controlling the rotation way.
Each time the arduino boot up (by connecting the USB or the 9V) also when I established a serial connection, the motors impulse at full speed for really short time.
The pin out from the arduino are connected directly to the motor board ; Do I need some kine of filter like capacitor, resistor ?
Do I need shielded cables ?
see the picture of the motor card bellow, bought on Ebay