Challenge to myself: Build an ornament for the Christmas tree in the few hours before Christmas Eve dinner.
I grabbed an Arduino the size of a coin I've been playing with called a "TinyDuino," from Tiny-Circuits, along with a little stash of LEDs I got from from Evil Mad Scientist.
Using the TinyDuino's prototyping board, I decided to solder the positive (long) ends of six LED's into the board so they radiated around it like this:
I bent the positive leg at a right angle before soldering it in and made sure that each LED's negative wire (the shorter one) was sticking up.
Once all six were securely attached, I had to figure out how to connect the negative legs to each other -- and also to one of the ground (GND) holes on the board. I decided to make a little star of copper tape on a piece of cardstock, and then cut it out in a small circle. I stuck the copper star under the negative LED legs, bent them each to be more flush to the board, and then soldered them on. Finally, I ran a little wire from the copper star to one of the GND holes on the board.
The TinyDuino microcontroller comes on another board, as does the USB adapter to program and power it. But the USB adapter outlet itself was bumping up against my soldering job. So to fit them all together, I actually had to include yet another random board (in my case, an accelerometer board.
Then, it was time to plug in the board and code it up!
I was hoping a 3v button battery in the holder on the back of the TinyDuino would power all of the LEDs nicely, but it was a little too weak. So I ended up running a USB cable to an A/C adapter plugged into the tree lights. That kept it powered and bright. (Another possibility would be to wire in a rechargeable battery.)
And all done before dinner.
After the holidays, I'll keep the prototyping board with the LEDs attached for next year, and return the TinyDuino and the other boards to the toy box.