Blinking Our First LED

Electricity is a strange thing to start with. You can't see it, you can't hold it, and the only time most people notice it is when it stops.

So we borrowed water. Pipes for wires, pressure for voltage, a narrow pipe for anything that slows the flow down. It isn't a perfect picture, but it gave fifteen people a way to imagine something invisible, and that was enough to begin.

Then the picture had to meet the real thing. A breadboard, an LED, an Arduino UNO. Open circuit, nothing. Close it, light. Every question after that came from somebody trying to make the water story match what was on the table in front of them, and there were a lot of questions.

The part I remember most came near the end. Each student typed a few lines of code, pressed upload, and an LED on their own breadboard started to blink.

It's a tiny thing. A light going on and off. But it's also the first time words typed on a screen reach out and move something physical, and you can see it land on people's faces. Code stops being something that lives inside a computer.

All fifteen got there by the end of the session. As a first page for the programme, I couldn't have asked for better: something invisible, made visible, by people who had never wired a breadboard before that day.