While I was making the InkShield I thought of a very interesting project that it would be perfect for, a ticker-tape style printer. The reason this is so nice is that a ticker-tape machine has a fixed head and only one axis. This makes for a very simple design.
I thought about several ways of doing this and finally settled on a serial printer design with a Processing.org “driver” on the PC side. The advantages of this approach are that I did not need a Ethernet shield and I could minimize the font table overhead, ~100 characters @ 24 bytes each = 2400 bytes, on the Arduino. The other advantage is that the printer does not care what it is printing and you can send arbitrary 12 pixel high “bitmaps”.
I am using a Darlington array to drive the unipolar stepper motor as shown here.
The current PC side software accesses Twitter and reads tweets containing “#tickertest”, if it finds one it sends it to the printer and then searches again. If it finds a new tweet it prints that as well and repeats the search.
Once I clean-up the code a little bit I will share it on github.
I will try to get a decent video of it in action and post that soon as well.