CAKEBOT: Stepper Motor Issues

 After our insightful meeting on Sunday, the CAKEBOT team dived into some hard science. Specifically, Griffin and I (the Sensors/Software sub-team) looked into having the platform rotate -- rather than trying to rotate the platform by hand or change the position of the frosting nozzle. To do so, we looked into using a stepper motor (360-deg versus a 120-deg Servo motor) and using the Adafruit Arduino Motorshield from a previous lab.

Coding-wise, I used the sample Adafruit code to test out the four types of motor-turns: single coil, double coil, interleave, and microstep.  Double coil allows for greater torque while microstep allows for smooth, continuous turns or "steps." Interleave alternates between single and double coil for stepping. The code worked beautifully, but we painfully discovered that the motor we were using was drawing more current than the Adafruit Motorshield could supply, causing quite a bit of smoking on the chips. We sought the advice of Siddhartan and ninja Forrest for ways to prevent overheating and they both directed us to thermal epoxy. Applying a metal slab with deep vents on top of the chips would increase the surface area and allow air to flow through the slits of the metal slab for greater cooling. However, for whatever reason, the epoxy glue was not drying properly and the slabs continued to fall off.

Another suggestions was to look for another stepper motor driver that could supply the necessary current for our stepper motor. In our preliminary search, we found that the ones that could handle the motor's current were high-grade, industrial drivers (aka expensive) and that they came with other features that would be useless to us. We'll keep looking around and hopefully, we can lay out the types of motors we'll need for all our actuators in the mechanical design.

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