I am working on a Robot that will utilise a differential drive with two DC motors. For that job I’ve chosen the 12V DC Motor 251RPM with Encoder by DFRobot. When implementing these motors and one of the encoder channels (I only care about rpm) the reading changes with outside influences like picking it up or even getting my hand only near it. Also if both motors are running or only one already makes a difference. I am kind of lost in finding the cause. I read the encoder channel using an interrupt on an arduino uno and increasing a counter. The motors are driven by a motor controller and an external battery. The command for the intended motorspeed is send via pwm.
Thanks in advance