The set-up of our final product.
Close-up of the final set-up of the wheel-refeeder mechanism.
Close-up of the final set-up of the 3D printer clamping mechanism.
Schematic overview of the pipette tip refilling process used in our product.
To start, some pipette tips are added to the refeeders by hand. Then, the Arduino code controlling the timing of rotation and angle of tilt of the wheel and refeeders is uploaded to the Arduino MEGA 2560 board via Arduino IDE, initiating movement of the wheel and the refeeders.
The wheel is set to rotate and stop at fixed time intervals, during which pipette tips will fall either through the funnel, out of the wheel onto the refeeder, or out of the set-up. When the wheel stops, the refeeders will rotate to a fixed angle, tilting towards the wheel to allow any pipette tips on them to roll back into the wheel. This cycle repeats itself infinitely, allowing for a constant flow of pipette tips through the funnel.
After falling through the funnel, the pipette tips will fall into the ramp, which has a gap of increasing width as the pipette tip falls from the top to the bottom of the ramp. This gap was carefully engineered to ensure that only pipette tips falling tip-first instead of hole-first will enter the ramp.
Anatomy of a pipette tip.
Only pipette tips sliding into the ramp tip-first will successfully enter the ramp and assume the position necessary for it to be picked up by the micropipette during the clamping step.
Once the pipette tips have successfully entered the ramp, our G-code will be uploaded to the Arduino MEGA 2560 board attached to the 3D printer. The 3D printer will lower the micropipette and allow for it to pick up the pipette tip oriented in the correct orientation in the ramp. It will then bring the micropipette with a pipette tip attached to the next empty position on the pipette tip box, before dropping it into the empty hole.
Here’s a video that showcases our final prototype in action! https://drive.google.com/file/d/1Zt3Aih1ttk28ITvjX8cQQIyj5fh9Bka1/view?usp=sharing