The original motor support was designed to accommodate a Pololu High-Power 12V DC motor with a 20.4:1 gear ratio, as was seen in the figures from the CAD Model section of our Design Process page. This motor was selected because of its high torque output and desired operational speeds. During our initial testing, we observed that the motor was unable to rotate at a low enough speed without stalling. Due to this, we made a decision to switch over to a stepper motor due to its ability to rotate at lower rpms without stalling.
Figure 5.1. Pololu DC Motor and NEMA Stepper Motor
After printing a new motor support and input pin, the stepper motor was able to successfully power the mechanism. Control of the stepper motor was achieved via an Arduino Uno R3 with an Arduino Motor Shield Rev3. Figure 5.2 shows the wiring connections required to control the stepper motor with the Arduino components, and Figure 5.3 shows the Arduino code that instructs the stepper motor what speed to rotate at.
Figure 5.2. Wiring Connections Between Stepper Motor and Arduino Motor Shield Rev3
Figure 5.3. Arduino Control Code