For IR development I've always fetched the thin cardboard tube that you find inside a roll of toilet paper. First off wrap the tube end to end with black plastic electrical tape. Then position the tube so the IR receiver is nestled down inside of one end of the tube. Use more tape around the back of the IR receiver and up onto the sides of the tube so that it both holds the tube in place and seals out light from coming in the near end of the tube.

Arrange this assembly in your development work area. I've then typically taped the IR transmitter to the other end of the tube so that the only thing the IR detector will see is the IR light coming from the transmitter. It is also possible to position this so that you can simply pickup the IR transmitter and aim it into the end of the tube.

If you find that works too crappy (pun intended) you could go for the longer tube from a roll of paper towels to give the IR receiver even more tunnel vision.

Michael Karas