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3.2.2 Infrared Obstacle Avoidance
3.2.2.1 Introduction of Infrared Obstacle Avoidance Sensor
Infrared obstacle avoidance module is a pair of infrared transmitting and receiving tubes, the former
launches a certain frequency infrared, the receiving tube will receive the reflected infrared when the infrared
detects the obstacles. After the signal is processed by the comparator circuit, the green LED lights, and the
signal output port outputs digital signal at the same time (a low level signal). The detection distance can be
adjusted through the potentiometer knob, the effective distance range is 2-30cm, the working voltage is 3.3V-
5V. The sensor uses infrared, so the anti-interference ability is very strong, the measurement accuracy is very
high when the distance is moderate. In addition, the module can be assembled easily and used conveniently,
it can be widely used in robot obstacle avoidance, car obstacle avoidance and the black&white line tracing
and many other occasions.
3.2.2.2 Working Principle
1, The module output port OUT can be directly connected with the IO port of the microcontroller, and
directly drive a 5V relay; the connection mode is: VCC-VCC; GND-GND; OUT-IO (A3 and A4), as shown
in Fig.3.2.9 and Chart 3.2.1.
2, The module uses the 3-5V DC power as power supply. When the power is on, the indicator will light.
3, The diameter of installation hole is 3mm, you can use the same size screws (screws in the kit).
Pin wiring definition (only for reference, you can define according to your own ideas):
arduino Uno
3.2.2.3 Module Parameters
The working principle of infrared obstacle avoidance sensor is very simple, that is the reflection property
of objects. In a certain range, if there is no obstacle, the infrared ray emitted will gradually weaken because of
the farther distance of transmission, and finally disappear. If there are obstacles, the infrared will be reflected
to the receiving head. As soon as the sensor detects the signal, it can confirm that there are obstacles in front
of the circuit board, the green indicator will light, the OUT port continuously outputs low level signal to MCU
at the same time, the MCU conducts a series of analysis to ensure that the two wheels of car works properly
and avoids the obstacle beautifully. The schematic diagram of the sensor is shown in Fig.3.2.8. Infrared
detector can be divided into active and passive according to its working mode.
Active infrared detector is equipped with infrared light source, it can detect the location of the object
through covering the light source, reflection, refraction and other optical means.
VCC
GND
A3
A4
Chart 3.2.1 Pin Wiring Definition
Infrared Obstacle Avoidance Module
VCC
GND
The left module
The right module
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