My entry for the Internet of Holiday Lights is an electro-mechanical wreath.
My first blog post was a brain dump of possibilities.
In my second post I made a paper prototype.
My third post was about getting the Arduino Yun up and running.
In the fourth post I used the Linux part of the Yun to get at the current date and time.
I have now found a stepper motor to drive my wreath's optical filter.
The quest for a motor
I have a few dc motors in my scrap parts box,and a small servo motor. I 'm looking for something with a more mechanical look and feel. I want a gearbox in my design.
I opened an old car cassette player and a defect flatbed scanner.
Because I don't have the correct sized Torx driver, I couldn't get at the mechanism without getting medieval. I was more lucky with the scanner.
It 's easy to open (this one particularly because it has been dropped from a few stairs by one of my children a while ago).
I was able to get the motor out with the gear mechanism intact. It's a Neocene stepper motor. There's loads of info available on the internet on this motor and how to drive it.
Driving the stepper motor
I've been looking for several options. I could recover the driver chip from the scanner PCB, or build my own H-Bridge. I had just enough old school transistors available to build a prototype on breadboard.
The breadboarded example worked. I then decided to move the circuit over to the smallest protoboard I had available.
And that's when Murphy joined the party 
You can't see it because of the silkscreen, but this protoboard (the top one on the photo above) is not what it seems. Even though it looks similar to the one on the bottom, the top one has pads connected in groups of 3.
Of course, I didn't spot that while building up my circuit, so it only showed up when I was measuring the circuit before first power on.
The transistors were parts I had recovered from an old tape deck. The pins didn't survive my attempt to desolder them this time.
So I made a shopping list for new components (using European style transistors of the BD13X family).
This morning I went to the local electronics shop (yes, open the day before xmas eve) with my list.
Turns out that they have a Velleman motor kit available.
The price difference between the kit and a set of loose components with stacking headers was not big.
So I decided to give myself a treat for xmas and bought my own presdent: the KA03 motor kit.
I was planning to use spare components as much as possible for the design, but I gave in this time. I'll be able to recover the motor driver for later use.
I'll spend part of my xmas holiday on building a Velleman kit. That's the first time since the mid-80's.