Yesterday’s post introduced the robot Myra and I have been working on. Here’s the first part we built:

It’s basically a backplane for the LED blinker component. Or to put it differently: a simple persistence-of-vision (POV) unit, using a JeeNode, and Output Plug to drive a few LEDs. Only the output plug was soldered-in permanently. The removable JeeNode allows it to be easily programmed and re-used, and the removable LEDs allow trying out different units. This turned out to be important, because I only had a few green LEDs when starting this, and had no idea then as to what sort of LEDs would give the best POV results later on.

Myra did all the soldering. Here are the two LED mounts we ended up with:

The one on the left is the super-duper LED concoction we built as final version. The one on the right was great for initial testing.

Everything is held together with rubber bands, zip-lock ties, tape, and ample amounts of hot glue (once verified to work!) – hacking at its best, clearly:

Here’s the LED blinker with the final LED strip, side view:

Side view close-up – with the foam board cover:

Bottom view:

Seven blue LEDs, ready to shine very brightly and controlled by the JeeNode.

The software started out very simple, of course. Things like this, just to make sure it all works:

This is the main part of what is more or less the final twitLEDs.pde sketch:

I found a suitable font table by googling around a bit. This is needed to go from ASCII characters to dots-in-a-readable-pattern. No room for Unicode (don’t laugh: some tweets are in Japanese and Chinese, and they won’t show properly).

The amazing bit is that everything worked essentially on first go. It blinked! But does it blink in the proper pattern? Our first test consisted of Myra taking a long-exposure shot, as I waved this thing around in the air – with the lights off. Liesbeth tracked progress through all the shrieks and laughs… but from a safe distance :)

Yippie. It really works!

Tomorrow: driving around without bumping into things.