IR Obstacle Avoidance Sensor Module
Short-range IR proximity sensor with an adjustable threshold — perfect for line-following robots.
A low-cost infrared proximity sensor with an onboard potentiometer for tuning detection distance, the standard choice for line-following and obstacle-avoidance robots. It works by emitting an IR beam and measuring the reflected signal strength bouncing back off nearby surfaces, outputting a simple digital signal when an object comes within the adjustable detection range — an inexpensive way to give a small robot basic 'something is close' awareness without the complexity of an ultrasonic or ToF distance sensor.
Specifications
| Sensor type | IR reflectance-based obstacle/proximity sensor with onboard comparator |
| Operating voltage | 3.3V–5V DC |
| Operating current | ~20-25 mA typical |
| Detection range | ~2cm-30cm, adjustable via the onboard potentiometer (exact max range varies by board revision) |
| Output | Digital output only on most versions — goes LOW when an object is detected within range (active LOW is common but check your specific board) |
| Sensitivity adjustment | Onboard trimmer potentiometer sets the effective detection distance |
| Surface dependency | Detection distance varies with target surface color and reflectivity — dark or non-reflective surfaces are detected at shorter range than light/reflective ones |
| Interface | Single digital output pin, read directly as a HIGH/LOW input |
Pinout
| Pin | Name | Description |
|---|---|---|
| 1 | VCC | Power, 3.3–5V DC |
| 2 | GND | Ground |
| 3 | OUT | Digital output — active LOW when an obstacle is detected within the adjusted range |
Adjust the onboard potentiometer while testing against your actual target surface (e.g. the specific line-following track or wall material), since detection range shifts noticeably with surface color and reflectivity — a setting tuned against a white wall may under- or over-trigger against a black line-following track. Multiple sensors mounted close together on the same robot chassis can occasionally cross-interfere with each other's IR beams; angling them apart slightly usually resolves this.
Variants
The basic IR obstacle sensor is the cheapest and simplest option for beginner robot kits that just need a binary 'something's there' signal. If the project needs to know how far away an object actually is (rather than just a threshold trigger), a Sharp GP2Y0A21 or, better yet, a VL53L0X gives meaningfully more useful distance data.
| Variant | Temp range | Hum range | Accuracy | Protocol | Price |
|---|---|---|---|---|---|
| IR obstacle sensor (3-pin, digital output) | ~$0.50-1.50 | ||||
| Sharp GP2Y0A21 (analog IR distance) | ~$5-10 | ||||
| VL53L0X (laser ToF) | ~$3-6 |