/Features: Stable performance and precise distance measurement High-precision module with 2 cm minimum detection distance Wiring: VCC, Trig (control pin), Echo (output pin), GND Usage: Trigger the module by sending a 10 µs or longer high-level signal to the Trig pin. The module will automatically emit eight 40 kHz ultrasonic pulses and detect the echo. When an echo is received, the Echo pin outputs a high-level signal whose duration corresponds to the time taken for the ultrasonic wave to travel to the target and back. Distance = (Echo pulse width × speed of sound in air (340 m/s)) / 2. Continuous measurements support real-time distance monitoring. Module working principle: (1) Trigger ranging using an IO pin with a ≥10 µs high-level pulse; (2) Module automatically transmits eight 40 kHz ultrasonic pulses and detects echo return; (3) Upon echo detection, the Echo pin outputs a high-level signal. Pulse width equals round-trip time of ultrasonic wave. Distance is calculated as above. Specifications: Type: HC-SR04 (4-pin) Operating voltage: DC 5V Quiescent current: < 2 mA Output level: High = 5V, Low = 0V Sensing angle: ≤ 15° Detection range: 2 cm – 450 cm Accuracy: ±0.3 cm Note: Slight variations in appearance or labeling may occur between batches without affecting functionality. Material: PCB Color: As shown Package Contents: 1 × HC-SR04 Ultrasonic Sensor Module