HC-SR04 Ultrasonic Distance Sensor

The HC-SR04 is the ultrasonic rangefinder that shows up in almost every beginner robotics tutorial — two transducer "eyes" that send and receive a chirp, and a timing circuit that turns the echo delay into a distance.

How it works

• Send a short pulse on Trig, and Echo goes high for exactly as long as the round trip takes
• Typical usable range is about 2 cm to 4 m
• Runs on 5 V DC
• Works in low light and on most solid surfaces

On the board

"HC-SR04" is silkscreened directly on the PCB — the same reference design used across almost every tutorial and Arduino library online, so example code written for one board runs on this one.

Pairs well with

• Obstacle-avoiding robots and reversing sensors
• Water-tank and bin level monitoring
• Presence detection for interactive displays

Compatibility

Arduino UNO/Nano/Mega directly. Raspberry Pi and ESP32 need a voltage divider or level shifter on Echo, since their GPIO reads 3.3 V, not 5 V.

Shipping

Dispatched from New Zealand with courier delivery nationwide, including rural addresses. Prices are in New Zealand dollars.