In this Instructable I demonstrate how to build a sample rotator using Erector set parts and littleBits. The sample rotator, or media rotator "is a common piece of standard laboratory equipment that is used for continuous mixing of lab samples, for example for slowly reacting or dissolving components" (1). I've broken the process of building the rotator into six steps. First, build the rotator base. Then build the support to prop up the rotator base. Next build what I call the "windmill," or the arms where the centrifuge tubes containing the samples are attached. I then demonstrate different methods for attaching the centrifuge tubes to the rotator and how to build the circuit to drive the littleBits motor module. Finally, I show the adjustable power supply wall-wart I use to power my littleBits projects.
Update: My littleBits sample rotator was featured on Dangerous Prototypes!
littleBits are color coded electronic modules that connect together magnetically to create simple electronic circuits. They are designed for ages 8 and up so hobbyists, designers, makers, and artists can add light, sound, and motion to their crafts and projects. Since they connect up magnetically (no need for circuit boards, breadboards, or solder), you can’t accidentally connect them the wrong way. With littleBits you can quickly build electronic circuits in a matter of minutes.
The color coded modules are divided into four categories. Blue, for power, currently includes three modules—the power module to which you connect a 9 volt battery, a coin battery module, and a USB power module. Pink for “input,” currently includes almost two dozen modules such as push buttons, switches, potentiometers, light sensors, and so on. Orange, for “wire,” includes several wires, branching connectors, and logic gates. Finally, the green “output” components include a little over a dozen modules such as motors, a fan, a buzzer, several kinds of LEDs, and a speaker.
An example of a circuit might be the blue power module connected to a green motor module. Switch on the power switch located on the power module and the motor spins. (2)
(1) Source: http://www.teklalabs.org/sample-rotator