Build Raspberry Pi Pico based Ultrasonic Distance Meter

This ultrasonic distance meter uses a Raspberry Pi Pico paired with an HC-SR04 ultrasonic sensor and five LEDs on a breadboard to measure and display distances without physical contact. The HC-SR04 sensor operates by emitting a brief, high-frequency sound wave burst when its trigger pin is activated by the Pico. This sound wave travels through the air until it hits an object and bounces back as an echo, which the sensor detects on its echo pin. The Raspberry Pi Pico, programmed using MicroPython via the Thonny IDE, measures the exact time interval between sending the sound pulse and receiving the reflected echo. Using the known speed of sound in air, the Pico calculates the precise distance to the object. To make this data easy to read visually, the circuit uses five LEDs connected to the Pico's general-purpose input/output (GPIO) pins using jumper wires. As an object moves closer to or further from the sensor, the Pico dynamically turns the LEDs on or off in a graduating sequence. For instance, when an object is far away, fewer LEDs light up, but as the object approaches, more LEDs illuminate to indicate increasing proximity. This combination of digital timing, mathematical calculation, and visual output transforms simple electronic components into a functional measurement tool.