Raspberry Pi Pico Parking Barrier (SG90 Servo + 2 LEDs + Button + Buzzer)

A small model of the boom barrier at a car park entrance! Press the button and the **Raspberry Pi Pico** raises the arm smoothly with an **SG90 servo** as the **green LED** comes on. It stays open for 3 seconds, then lowers slowly with a **flashing red LED** and warning beeps from the **buzzer**. Press again while it is lowering and the arm **rises at once for safety**. Servo control, a state machine and non-blocking timing in one project.