Add precise "eyes" to your Arduino, Raspberry Pi, or robotics project with the HC-SR04 Ultrasonic Distance Sensor. This module is renowned for its stable performance and high accuracy, making it an excellent choice for non-contact distance measurement, object avoidance, and liquid level detection. It offers a wide detection range from 2cm to 4.5 meters with an impressive precision of up to 0.3cm. It even handles super-close "blind spots" (3cm), ensuring you get reliable data. Key Features: High Precision: Ranging accuracy can reach up to 0.3cm for stable, reliable data. Wide Range: Detects distances from 2cm all the way to 450cm (4.5 meters). Minimal Blind Spot: A small 3cm blind spot makes it highly effective for close-proximity detection. Broad Compatibility: Works perfectly with Arduino, Raspberry Pi, and other 5V microcontrollers. Low Power Consumption: Quiescent current is less than 2mA, ideal for battery-powered projects. Focused Detection: A sensing angle of 15 degrees helps to measure objects directly in front of the sensor. How It Works: Trigger: Supply a high-level signal of at least 10us (microseconds) to the Trig pin. Transmit: The module automatically sends out eight 40kHz ultrasonic square waves. Receive: The module automatically detects if a returning pulse signal is received. Output: If a signal returns, the Echo pin will output a high-level signal. The duration of this high-level signal is the total time from transmission to reception. Calculation: Distance = (High-Level Time $\times$ Speed of Sound (340m/s)) / 2 Product Specifications: Working Voltage: DC 5V Quiescent Current: < 2mA Output Signal: High level 5V / Low level 0V Sensing Angle: $\le$ 15 degrees Detection Range: 2cm - 450cm Pinout: Vcc, Trig, Echo, Gnd