Test and Adjustment of IR Sensor System
Educational Revision BEST Robotics Inc © 2019 Page 3
Step 2: Setup and Test Beam Breaking Operation
This is the simplest testing option, needing only a +5V power supply. The IR emitter runs
continuously. It is suitable for a “beam break” application.
Note: Be sure to get the polarity of the power supply correct.
Using a 3-wire cable, connect the power supply to the receiver board. The male end of the cable
connects to the power supply. Using a solderless breadboard makes this a lot easier than trying to clip
on to those tiny connector pins without shorting anything. The female end of this cable plugs onto 3 of
the 4 pins on the receiver board (J2) with the black wire connected to the pin closest to U2 (the dark 3-
pin IR detector IC). The 4th pin on the receiver board, the pin closest to the edge of the board, remains
unconnected.
Using another 3-wire cable, connect the receiver board to the transmitter board. The male end
of the cable plugs into the 3-pin socket on the receiver board (J3), with black wire connected to the
same end as that of the first cable on J2. Note that the cable’s connector will be offset 0.1” from the
first cable’s connector. The female end of this cable plugs onto the 3-pin connector on the XMT board
(J1), with the black wire connected to the pin closest to the bright yellow capacitor (C2), away from the
corner of the board.
When you apply power the red LED on the XMT board should turn on. You can monitor the
operation using the red LED on the RCV board. When the RCV board detects the signal from the XMT
board, the red LED on the RCV board will turn on. When you block the IR signal or turn the XMT board
in a different direction, the red LED on the RCV board will go out. Note that as drawn in figure 1 the
transmitter emits light up, out of the page, and the receiver is “looking” toward the bottom of the page.
Please see assembly instructions for more details.
