Maker Faire was AWESOME! What a crazy event that was. I am proud to say that the Track A Keg received an Editor’s Choice Award.
The interesting thing was the coolest display I had was not either of the projects that I submitted! It was in fact the Yeast Stir plate. While I always thought it was about functionality, the visual affect is pretty cool, and it attracted a lot of attention. So, for all those who saw it, I am going to not only post how I built the one I had, but I’m going to work on a way cooler one that hopefully will be published in Make magazine someday.
In any case, the short rundown is this:
Items required: Cigar box (or equivalent), computer fan (12v or so), old cell phone charger (voltage close to computer fan), switch (if you want to turn it on and off), stir bar (google it–Science supply stores and homebrew stores sell them), hard drive magnets–the rare earth magnets found in the arm of the inside of an old hard drive, and if you want to control the speed, a rheostat will work. I had an LM371 voltage regulator to keep the current up as well, but this may not be necessary if you don’t want to control the speed as much.
Inside the stir plate
Glue the rare earth (hard drive) magnets to the fan, put it in the cigar box, and see how much distance there is between the top of the box and the magnets. You may need to add something underneath the fan to raise it so that the magnets are close to the top, but not touching. The closer they are, the better the magnetic field will be.
Once you have done that, you can connect the fan to the cell phone charger, which will make the fan start up. You do need to have the vase (I got mine from Wal Mart for about $5), water, and stir bar in place before you start it. If the fan runs too fast, it may cause the stir bar to fly off, and rattle on the side.
More to come–I am going to look at finding parts that will work without the regulator, and also post the regulator circuit for those interested in controlling the speed!