6.5 Implementation

Fabrication and Assembly

In an ideal world, the design would be made out of a biocompatible material such as stone or ceramic, but due to our limited time and budget, we elected to fabricate the final design out of different, less expensive materials as a proof of concept for a hypothetical product. The body of the design and link lengths are constructed out of laser-cut wood fastened together with wood glue. The body houses mounting points for all mechanical components and provides a holding space for electronics. Both the mortar, grinding wheel (pestle), and gears are made of laser-cut acrylic (due to less friction being associated with the acrylic versus wood). Small 3D printed connectors were made to connect the links to the metal rods that oscillate linearly and move the grinding wheel. The figure below shows the final CAD assembly for the design.

Open

Electronics, Circuitry, and Software Development
As the entire system is driven by a singular stepper motor, the electronics and circuitry for this project were relatively simple. The input for the system is a potentiometer that controls the speed at which the motor runs. The potentiometer is linked to the input pins in an Arduino microcontroller (blue board), which translates the potentiometer values into those readable by the motor controller (red board). Those values are then transmitted to the motor controller, which then powers the motor. The electrical circuit is powered by a 12V power supply that is plugged into a wall outlet. The circuit diagram shown below illustrates the connections.