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Open Source Test Tube Roller
This test tube roller is a simple and cost-effective test tube roller. It is made from 6mm acrylic, cardboard, a DC motor, a potentiometer, and one custom 3D printed hub. The potentiometer allows for variable speeds by limiting current to the motor.
Build
Plans
The mounting holes and 3-D printed hub may need to be modified based on the DC motor being used.
Parts
The following are needed to build the roller:
- 6mm Acrylic sheet
- DC Motor
- Power supply with matching voltage to motor
- Potentiometer
- Power Switch
- #8-32 screws, nuts, and locknuts
Notes
A 12V wall wart was used for this but most appropriate power sources can be used.
Both a power switch and transistor are optional and can be used to regulate the power and speed of the motor.
Assembly
- Download the original CAD files for the “motor_front” and “hub” and adjust the motor mount pattern and motor hub diameter to match the dimensions of your motor
- Laser cut dxf files and your modified “motor_front” plate
- 3D print the motor hub
- Screw together frame and motor. Use lock nuts on pivot joints
- Solder the power supply to the motor with the power switch and potentiometer in series
- Wrap rubber bands around test tubes before inserting into hub. This is to prevent slipping as the cardboard friction fit can sometimes slip over time
Final Assembly
Completed Assembly
The design was mainly based around the DC motor since it was the only one that could be used at the moment. Future designs can be modified to fit other DC motor's.
The hub attaches the tube holder to the motor's shaft. The hub was customized to the diameter of the shaft; it was then press fitted onto the preheated shaft to ensure a solid fit.
A second plate made of foam board was attached to provide additional support to the tubes.
The lower support arms swing to adjust the angle of the rotor head.
