The **B-02-R** typically refers to a specific model of an **Infrared (IR) Obstacle Avoidance Sensor Module**, widely used in Arduino, Raspberry Pi, and DIY robotics projects. --- ### 1. Component Overview The B-02-R module is an active infrared sensor that detects the presence of objects by reflecting light. It consists of a transmitter (emitter) and a receiver (photodiode). ### 2. Main Electronic Parts | Component | Function | Characteristics | | :--- | :--- | :--- | | **IR Emitter** | Sends out an infrared signal. | Clear LED-like component; 950nm wavelength. | | **IR Receiver** | Detects the reflected IR light. | Black-tinted component to filter ambient light. | | **LM393 IC** | Voltage Comparator. | Compares the signal from the receiver against a threshold. | | **Potentiometer** | Sensitivity Adjustment. | Rotatable screw to change the detection distance (typically 2cm - 30cm). | | **Resistors/Capacitors** | Signal Conditioning. | Filters noise and limits current to the LEDs. | | **Power LED** | Status Indicator. | Lights up when the board has power. | | **Signal LED** | Output Indicator. | Lights up when an obstacle is detected. | --- ### 3. Pin Configuration The module generally features a 3-pin or 4-pin header: 1. **VCC:** Power supply (typically 3.3V to 5V DC). 2. **GND:** Ground. 3. **OUT:** Digital Output (LOW when an obstacle is detected, HIGH when the path is clear). 4. **EN (Optional):** Enable pin (found on some variations to turn the sensor on/off). --- ### 4. Technical Specifications * **Operating Voltage:** 3.3V to 5V DC. * **Output Type:** Digital (0 and 1). * **Detection Angle:** ~35°. * **Effective Distance:** 2cm to 30cm (Adjustable). --- ### 5. Working Principle The **IR Emitter** constantly emits infrared rays. When an object enters the detection range, the rays hit the object and reflect back to the **IR Receiver**. The **LM393 Comparator** processes this change in voltage; if the reflected signal is strong enough (surpassing the threshold set by the **Potentiometer**), the **OUT** pin pulls to a Logic LOW state, and the onboard **Signal LED** illuminates.