IR Infrared 2 - 30cm Obstacle Detaction Sensor Module [AD-032]

The basic concept of IR(infrared) obstacle detection is to transmit the IR signal(radiation) in a direction and  a signal is received  at the IR receiver when the IR radiation bounces back from a surface of the object.

There are two potentiometers on the module one controlling operating frequency (centered at 38 kHz) the other controlling intensity. The detector was designed for 38 kHz and the onboard oscillator circuit is based on a 555 timer. Tweaking gives a little better range but I'd suggest leaving it alone because the useful range is narrow.

The maximum reliable range in some test was around 30-40 cm and depended on the type of material.
A smooth white surface worked far better than a black or rough surface.

Features

IR Sensor for Obstacle Avoidance KY-032 (AD-032)

Connect to Arduino

// IR Obstacle Collision Detection Module

int LED = 13; // Use the onboard Uno LED
int isObstaclePin = 7; // This is our input pin
int isObstacle = HIGH; // HIGH MEANS NO OBSTACLE

void setup() {
    pinMode(LED, OUTPUT);
    pinMode(isObstaclePin, INPUT);
    Serial.begin(9600);
}

void loop() {
    isObstacle = digitalRead(isObstaclePin);
    if (isObstacle == LOW) {
        Serial.println("OBSTACLE!!, OBSTACLE!!");
        digitalWrite(LED, HIGH);
    } else {
        Serial.println("clear");
        digitalWrite(LED, LOW);
    }
    delay(200);
}

Move your hand towards the IR LEDs.  As you near them, the Output LED on the module and the LED for pin 13 on your Arduino will illuminate.  Open your serial monitor and vary the distance of your hand while viewing the serial monitor. The output should show "Clear" to "OBSTACLE!!, OBSTACLE!!".