This isn’t exactly dot matrix printing, but the effect is similar. It’s nothing ground breaking, but it is cool, albeit useless. Some people at RIT came up with machine that will reproduce pictures given to it as prints made with drops of coffee. The coffee part isn’t required, any colored liquid will do, but coffee is readily available to most people, especially leftover coffee, so it was as good a medium as any.
The Arduino micro controller has 32KB of memory, which lets it print about an 80×100 pixel image. It scans the image and turns it into dots that then determine how long to hold open the drip nozzle. This creates variously sized dots that while still liquid look pretty good from afar. As you can see below, the resulting dried pictures is more blurry then the nice crisp dots:
Watch this pretty interesting, but all too quiet video of the process. It’s nice because it’s sped up, it’s boring because it’s quiet.