Christina Holman | Design Blog

This design review went very well for CAKEBOT. We took the feedback from our last review and tried to apply the criticisms and encouragement we received to this sprint. We were able to demonstrate a proper integration of the electronics, software and mechanics. Griffin updated the GUI for more tip changes, "Confirmation" dialogue boxes, and on-screen drawing. While he was out at You-Do-It, he brought me 2 limit switches for calibration and I also requested some safety switches, i.e. a master on-off switch and a confirmation (or "pause") button -- all to be mounted afterwards. Below is the presentation with updated goals and videos of the demonstration. (The form is now closed but we received great feedback).

Leading up to the second Design Review, CakeBot team attacked our project with a vengeance, ordering supplies for the frosting dispenser asap and building the frame for it, searching for new motors and drivers to build the actuators for nozzle and platform movement. Cassie and Emily, once the orders came in, worked on modifying the Wilton Decorator Pro to attach to a DC motor for up-and-down movement, i.e. pressure on the frosting container. Another stepper motor, compatible with the Adafruit Motorshield, was ordered and integrated by using a belt to move the nozzle/dispenser across the radius of the cake. Griffin and I also ordered a separate stepper driver from Pololu  to drive the Rotating Platform's "high-current" stepper motor. In testing our apparatus, with a finally-mounted Decorator Pro, we were able to observe three mechanisms: Extruding the frosting to create a border: The DC motor moves the plunger downwards at a constant rate while the platform rot...

After 2 sprints -- two week periods of building and planning -- teams are expected to present in front of the class and professors for questions and feedback. Our team were persistent in our design and build despite delivery delays, system failures and more so. Unfortunately, because the parts did not come in enough time, the mechanical system could not be built. However, Griffin and I were able to pull together a rotating platform with a pseudo-calibration switch as well as a basic GUI (graphical user interface) to choose different tip sizes and frosting patterns. Cassie was also able to laser-cut a wooden cube, where we could store all electronics, for the base of the entire mechanism. See the PowerPoint presentation that the CakeBot team delivered to the class and how we hope to attain the Final Goal in the next sprint/design period. (The feedback form is closed now.) The responses we received were encouraging but critical as we are a little behind schedule. Additional...

 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 ...