Hello friends! Today we will connect three HC-SR04 ultrasonic sensors to an Arduino Uno. A single forward-facing sensor is useful for a basic distance demonstration, but a robot may also need information from its left and right sides. The original project used this arrangement to discuss obstacle detection and movement between two walls. If you have not yet obtained stable readings from one module, begin with Interfacing an Ultrasonic Sensor with Arduino . Here we will build on that measurement function while addressing the main new issue: several sensors can hear one another. Adding more input pins does not automatically create independent acoustic measurements. We will preserve the original right, left and front pin assignments, trigger the sensors sequentially and report whether each re ...