I'm currently trying to install some IR sensors on an Arduino robot and am having issues with the sensor readings anytime the motors (2 of them) turn on.
I'm using an Arduino Uno connected to an Arduino Motor Shield. The IR sensors are Vishay IR detector modules powered from the regulated supply rail (5V) on the Arduino.
Anytime the motors are powered off, everything works just fine; that is when it detects IR the output of the sensor goes to GND.
But as soon as the motors turn on, the output keeps dropping to GND regardless. I used an oscilloscope to confirm that indeed there is high frequency (~10 MHz) noise. I'm assuming this is noise introduced into the supply by the motor/Motor Shield PWM control signal?
But isn't the whole point of a regulated 5V supply to provide a stable voltage?
I even tried connecting the sensors straight to the Battery (3300 MAh NiMh cells, so current draw isn't a problem) and it made no difference. I've also tried putting capacitors across the motor terminals, across the IR sensor Vin and GND, and also tried them across the Output and GND. No dice. So are the motors actually causing ripples on the Battery voltage?
This is the IR detector: http://www.pololu.com/file/0J19/TSOP34156.pdf