The **P-R4** typically refers to a specific model of **PIR (Passive Infrared) Motion Sensor** module widely used in security systems, lighting controls, and Arduino/Raspberry Pi projects. Below is a breakdown of its electronic components and technical specifications. --- ## 1. Core Electronic Components The P-R4 module is an integrated circuit assembly that translates infrared radiation into a digital signal. | Component | Function | | :--- | :--- | | **Pyroelectric Sensor** | The heart of the module; detects changes in infrared radiation emitted by living bodies. | | **Fresnel Lens** | The white plastic dome that focuses infrared light onto the pyroelectric element. | | **BISS0001 IC** | A high-performance signal processing chip that filters noise and manages the trigger timing. | | **Voltage Regulator** | Usually a 3.3V LDO regulator that allows the board to accept a wider input range (e.g., 5V-20V). | | **Potentiometers** | Two adjustable resistors: one for **Sensitivity** (distance) and one for **Time Delay**. | | **Diodes/Capacitors** | Provide circuit protection and smooth out power fluctuations to prevent false triggers. | --- ## 2. Technical Specifications Most P-R4 modules follow these standard electrical parameters: * **Operating Voltage:** DC 4.5V to 20V. * **Static Current:** < 50µA (ideal for battery-powered devices). * **Level Output:** High 3.3V / Low 0V. * **Trigger Methods:** * *L (Non-repeatable):* Stays high for a fixed time then goes low regardless of motion. * *H (Repeatable):* Stays high as long as motion is detected. * **Detection Angle:** < 100° cone angle. * **Detection Distance:** 3 to 7 meters (adjustable). --- ## 3. Pin Configuration The module generally features a 3-pin header for easy connection: 1. **VCC:** Power input (Positive). 2. **OUT:** Digital output signal (High/Low). 3. **GND:** Ground (Negative). ### Wiring Example (Pseudo-code Logic) ```python # Basic logic for connecting P-R4 to a microcontroller if sensor_pin == HIGH: print("Motion Detected!") turn_on_light() else: print("No Motion.") ``` --- ## 4. Adjustment Controls On the back of the PCB, you will find two orange or blue trim pots: * **Delay Time (Tx):** Adjusts how long the output stays "HIGH" after motion stops (usually 0.5s to 200s). * **Distance/Sensitivity (Sx):** Adjusts the detection range (clockwise increases sensitivity).