RAFTT - Rotating Apparatus for Test Tubes

The RAFTT is a device that rotates an array of test tubes according to user chosen settings. The RAFTT was built specifically for research experiments involving sleep deprivation of fruit flies, but can be adapted to similar experiments due to it’s modular design and settings.

The Challenge

Create a low cost device for a Neuroscience lab that would rotate irregular shaped test tubes at a specific frequency, angle, and duration.

Approach

Off the shelf components for these unique test tubes couldn’t be found, so parts were designed from scratch. To keep costs down the final product would use durable 3D printed material and laser cut acrylic instead of injection molded plastic. The body of the RAFTT and the control box were designed for and made by 3D printing. The stand and motor housing was designed for and made by laser cut acrylic. The entire system can be assembled or disassembled with a single allen wrench. The major electronic components included an arduino, 16x2 LCD, voltage regulator, and a rotary encoder.

Ease of Use

The device needed to be easy to use and intuitive for any researcher to use with minimal training. While the lab only needed the device to be set to a constant speed, frequency, and angle, I programmed the micro controller with a menu system in which the user could set each value. This design choice was to prevent unforeseeable issues and allow variations of the experiment. In addition, a USB connection is available on the control box if any firmware updates are needed.

Modular design

The body of RAFTT (blue parts) can be easily disassembled to be shipped, stored or have parts replaced. Each part of the body is connected via tracks and magnets which can be slid in or out of place. The use of magnets is also a means to secure the test tubes in the RAFTT or to raise all test tubes for easy access at the end of an experiment.

If a researcher needs access to a specific test tube this can also be achieved by pressing the appropriate lifting pin on the bottom.

Early Design Process

The type of test tubes used for this experiment was not known at the beginning of the project, so the focus of the project shifted from a rough mechanical design to the software and electronic design. The images below show the progression of the project in it’s early stages.