HC-SR04 Ultrasonic Sensor

HC-SR04 Ultrasonic Distance Sensor Module A low-cost, widely used sensor that measures distance with ultrasonic sound waves. It sends out a 40 kHz pulse and times the echo that bounces back, giving reliable non-contact readings from 2 cm to 400 cm. It works with Arduino, ESP32, ESP8266, Raspberry Pi, and most other microcontrollers, which makes it a popular choice for obstacle-avoiding robots, level monitoring, and parking sensors. Key Features Operating voltage: 5V DC Operating current: about 15 mA Frequency: 40 kHz Measuring range: 2 cm to 400 cm Accuracy: up to 3 mm Measuring angle: about 15° Trigger input: 10 µs TTL pulse Output: TTL echo pulse, proportional to distance Pins: 4 (VCC, Trig, Echo, GND) Dimensions: about 45 × 20 × 15 mm Pin Configuration VCC: 5V power Trig: trigger input Echo: echo output GND: ground Compatibility Arduino (Uno, Nano, Mega) ESP32 and ESP8266 (use a voltage divider or level shifter on the Echo pin, since Echo outputs 5V and these boards are 3.3V) Raspberry Pi (same level-shifting advice) STM32, PIC, and other microcontrollers Common Applications Obstacle-avoiding and line-following robots Parking assist and distance meters Water tank and liquid level monitoring Automatic door and proximity sensing Security and motion detection School projects and hobby electronics Package Includes 1 × HC-SR04 ultrasonic sensor module