Lab plate vortex/shaker from a 140 mm fan

I wanted an agitator that could do a bunch of different jobs in the lab, from mixing samples overnight to cleaning grinding beads in bleach. I also wanted to achieve this with a minimum of effort (and wanted others with only basic electronics experience to be able to do the same), so I put this together from a 140 mm computer fan and a multi-voltage power adaptor.

This tool performs two major lab functions: vortexing samples and vibrating the heck out of samples. The platform comfortably fits a 96-well plate, or one of those large square tube racks. You can just as easily use this agitator to mix up hobby paints or food colours.

Video demonstration of this Thing here.

This design is a fancier version of the DIY paint shaker described by Angry Dwarf! Miniatures.

How to use it

You have two ways of adjusting the machine to get it to do what you want: changing the input voltage via the power adaptor, and changing where the weight is located on the fan blade.

Having the weight closer to the center of the fan creates vibration. This is how your phone generates its vibrations, for example.

Moving the weight away from the center of the fan creates slow, circular oscillations, and this is what you want for mixing and vortexing.

I find that the best way to use the machine is to start it at the highest voltage/fastest speed, and then turn it down until you have the result that you want. Especially when your goal is to vortex samples, there's something about working backwards like this that helps the vortex motion establish itself.