Want to tell if a door is open? Use a Magnetic Switch. Sometimes called a Reed or Door switch, these come with two components, a wired piece and a magnet. When the door is open, the switch reports like a button that isn't depressed. When closed, the magnet completes a circuit inside the wired switch and current flows through the switch, reporting like a depressed button. We'll learn about Magnetic Switches, we'll wire one to a Raspberry Pi Pico and read it's state through a CircuitPython program, then we'll issue a challenge to create a door alarm that lights up an LED and plays an alarm sound if a door is open, and stop playing and lighting when the door is closed. We'll show the solution to the challenge at the end of the lesson.
Part of Prof. John Gallaugher's Physical Computing course. For more info, see: gallaugher.com...