# HC-SR04 ultrasonic sensor, distance 2–450 cm, 5V

> HC-SR04 ultrasonic sensor, compatible with Arduino, used for distance measurement and obstacle detection in robotics or automation projects. Operates at 5V, covers a range of 2 cm to 450 cm, with an accuracy of up to 0.3 cm. Connects via Trigger and Echo pins for easy integration into circuits.

- Page: https://sigmanortec.ro/en/ultrasonic-sensor-hc-sr04
- Price: 8.13 RON
- Availability: In stock; 1-2 zile
- Reference: 22017 · EAN: 5946598261001
- Category: Mechatronics and IoT > Sensors and Modules > Distance and Presence Sensors
- Package (shipping data): 0.008 kg
- Updated: 2026-10-11
- Shop: [Sigmanortec.ro](https://sigmanortec.ro/en/llms.txt)
- Prices: RON, VAT included; prices and stock as of 2026-10-22 03:39 (Europe/Bucharest)

## Description

Arduino compatible ultrasonic sensor, ideal for quick distance measurement and obstacle detection in robotics or automation projects. It operates at 5V, covers the range of 2 cm to 450 cm, offers accuracy up to 0.3 cm and simply connects via Trigger and Echo pins for easy integration into assemblies.
The HC-SR04 ultrasonic sensor is a contactless distance-measuring module that combines an ultrasonic transmitter and receiver on the same board, along with a dedicated control circuit. The sensor detects the presence of and distance to solid objects in front of it, and is commonly used in mobile robotics for obstacle avoidance, in parking systems, in measuring liquid levels in tanks, or in any project that needs a fast and inexpensive distance reading.
The operating principle is simple and based on the time of flight of sound. The Trig pin receives a TTL pulse of at least 10 us, after which the module automatically sends a burst of 8 cycles of ultrasound at 40 kHz and waits for the echo reflected by the object. The Echo pin stays at logic high for the entire time the sound travels back and forth, and this duration is converted into distance using the formula distance in centimeters equals time in microseconds divided by 58, or distance equals time multiplied by the speed of sound of 340 m/s and divided by 2. The effective measuring angle is approximately 15 degrees, and for correct results the target surface must have at least 0.5 square meters.
Among the main features are the two ultrasonic transducers visibly mounted on the front of the board, the oscillator crystal that clocks the control circuit, the signaling components, and the 4 interfacing pins marked Vcc, Trig, Echo and Gnd, accessible on a header with a 2.54 mm pitch. The module is powered at 5 VDC through the Vcc pin, with a typical operating current of 15 mA.
Through the two digital signals Trig and Echo, the sensor is compatible with Arduino, ESP32, STM32, Raspberry Pi and any other development board that has at least two GPIO pins, one output pin for trigger and one input pin for reading the echo.
Specifications:
Model: HC-SR04
Supply voltage: 5 VDC
Current consumption: approximately 15 mA
Ultrasonic frequency: 40 kHz, in bursts of 8 cycles per measurement
Trigger signal: TTL pulse of at least 10 us on the Trig pin
Echo signal: TTL pulse with duration proportional to distance, on the Echo pin
Detection distance: 2 cm - 450 cm
Accuracy: 0.3 cm
Measuring angle: 15 degrees
Interface: 4 pins Vcc, Trig, Echo, Gnd
Dimensions: 45 x 20 x 15 mm
Pinout:
Connector
Pin
Function
4-pin header
Vcc
5 VDC power supply
4-pin header
Trig
Trigger input, TTL pulse of at least 10 us to start the measurement
4-pin header
Echo
TTL pulse output with duration proportional to the measured distance
4-pin header
Gnd
Ground
Usage:
Connect the sensor’s Vcc pin to 5 VDC and the Gnd pin to the common ground with the development board.
Connect the Trig pin to a digital output and the Echo pin to a digital input of the development board.
If you are using a board with 3.3 V logic, such as ESP32, STM32 or Raspberry Pi, install a resistive divider or a level shifter on the Echo pin, because the sensor’s output signal is 5 V.
Generate a HIGH pulse of at least 10 us on the Trig pin to start a measurement.
Measure the duration of the HIGH pulse received on the Echo pin and calculate the distance by dividing the time expressed in microseconds by 58 for centimeters, or by 148 for inches.
Leave a pause of at least 60 ms between two successive measurements so that the echo from one measurement does not interfere with the next.
Mount the sensor so that the target object’s surface has at least 0.5 square meters and is as perpendicular as possible to the two transducers.
Avoid targets made of soft or absorbent materials, such as textiles or foam, because these attenuate the echo and can cause incorrect readings or no response.
Do not exceed the 5 VDC supply voltage and check the polarity of Vcc and Gnd before connecting.