Do You hear a sound when only one IR LED (right) is detecting an obstacle? if all is correct, You must hear a sound.
When an obstacle is detected, the received signal is sent to the receiving module which
will then instruct the robot to take evasive action:
a) When the emitting diode (IR led clear) to the right detects an obstacle, you will hear a single beep.
The left motor goes into reverse mode.
b) When the emitting diode (IR LED clear) to the left detects an obstacle, you will hear a single beep.
The right motor goes into reverse mode.
c) When the emitting diode (IR LED clear) in the middle detects an obstacle, you will hear two beeps.
The two motors go into reverse mode. Subsequently, the procedure explained in a) is followed.
d) When all three emitting diodes (IR LED clear) detect obstacles, you will hear three peeps.
The device then follows the procedure described above in c), but turning takes somewhat longer
If You hear no sound when covering one IR LED (clear), check if the IR leds are connected in the right position.
Because the IR leds has a polarisation. thus check the polarity of the IR leds.
The sensitivity may be affected by fading battery power and a change in environment.
Try to find the ideal position for the IR receiving module.
If this doesn’t solve the problem, You can bring it back to Your local shop for a check-up or repair.