HC-SR04 ultrasonic ranging module pinout

The HC-SR04 sends a 40 kHz ultrasonic burst and reports the round-trip time as the width of a logic pulse.

Four-pin module header

4 contacts Current package

ELECFREAKS ·

Four-pin module header

Face the two transducers with the connector below them. VCC, Trig, Echo, and GND run left to right.

Output · Outputs

The high pulse width measures acoustic round-trip time. The 5 V wiring below assumes a 5 V host.

ELECFREAKS HC-SR04 User Guide, §§ 2.3–2.5 and 3.1.

Pin	Signal	Direction	Function
1	VCC Supply input	Supply input	Primary device supply. Place the bypass capacitor close to this pin.
2	Trig Input	Input	A high pulse of at least 10 µs starts one measurement.
3	Echo Output	Output	The high pulse width measures acoustic round-trip time. The 5 V wiring below assumes a 5 V host.
4	GND Supply return	Supply return	Connect to the common ground plane or bench return.

Use one GPIO output to start the burst and a separate input timer to measure echo pulse width.

Parameter	Limit	Conditions and source
Supply5 V DC	5 V DC	The guide lists 15 mA operating current. ELECFREAKS HC-SR04 User Guide, §§ 2.3–2.5 and 3.1.
Trigger width10 µs minimum	10 µs minimum	The module emits eight 40 kHz cycles per trigger. ELECFREAKS HC-SR04 User Guide, §§ 2.3–2.5 and 3.1.
Ranging interval2 cm to 4 m	2 cm to 4 m	The documented range depends on target size, angle, and acoustic conditions. ELECFREAKS HC-SR04 User Guide, §§ 2.3–2.5 and 3.1.

This map follows the 5 V ELECFREAKS HC-SR04. Check the markings and voltage limits on lookalike modules.

HC-SR04 manufacturer documentation· ELECFREAKS HC-SR04 User Guide, §§ 2.3–2.5 and 3.1.