Arduino Day and the Fading LED

Arduino Day happens all over the world on the same day. Makers, schools, hackerspaces, people at their kitchen tables, all building with the same open hardware.

We were one small room in that. For many of the students, it was the first time they'd heard there was a community at all, that the board on their desk was shared by people everywhere, and that its designs were open for anyone to learn from.

That idea matters to me more than any single circuit. The tools aren't owned by a company you need permission from. They belong to whoever picks them up.

The making itself was gentle. Block coding instead of typed code, so the logic could be dragged and dropped and seen as shapes. First a blinking LED. Then a fade.

Block coding interface — Logic you can see the shape of

LED fading circuit — Not dimming. Blinking, very fast.

Muhammed Basheer facilitating the session — Walking through the blocks, one at a time

The fade is my favourite trick in all of beginner electronics, because it's a lie your eyes believe.

An Arduino pin can't actually make an LED half bright. It's either on or off. What it can do is switch on and off hundreds of times a second, spending more time on to look brighter, more time off to look dimmer. Your eye can't keep up, so it averages, and you see a smooth fade that doesn't really exist.

It's called PWM, and it's worth showing someone early. What you perceive and what's actually happening can be very different, and the difference is often just speed.

So that was the day. A global community, a shared set of tools, and a light that taught us not to trust our eyes completely.