With a standard old HC-SR04 ultrasonic sensor, an audio module and a servo to drive a custom gauge needle he’s made a device which can warn people around you if they’re too close for comfort.

For the transmitter, the ultrasonic transducer is simply tied to one of the digital pins on the Arduino. ... Posted in Arduino Hacks, Wireless Hacks Tagged arduino, HC-SR04, ...

Watch the demonstration video below to learn more about Zola’s project which uses TX and RX transducers desoldered from an HC-SR04 module, together with a pair of Arduino Uno development boards ...

Specifications of the ultrasonic sonar distance sensor that can be used with Arduino, Raspberry Pi, CircuitPython and more include : – Power & Logic Voltage: DC 5V – Current during measurment ...