I have a photointerrupter sensor that is near an electric motor in a scooter and i'm tyring to tap into it. When I tapped into the sensor with a wire, the scooter stops running. Initially I thought it was my speedo circuit but then i found out that if I tap into the sensor with just a plain wire the scooter would also stop running. The wire is not connected to anything! If the wire is long enough the scooter would stop running. This suggests that it is because of the EM waves of the motor cause voltage spikes in the wire tapping into the sensor and distored to the signal thus cause the computer to stop the motor. Can somebody tell me how to overcome this?