Inside [Klaus]’ device is an Arduino Uno, an HC-SR04 ultrasonic ... of the sensor, though, and the device can be easily reconfigured to sense a distance up to four meters. The board doesn ...

Most often ultrasonic transducers are used ... implemented using the Arduino’s Timer1. Those go to a circuit board he designed which modulates the carrier with the audio signal using a single ...

But if you’re just starting out, here’s a quick list of the most useful components for your Arduino boards ... if you don't ...