Our goal was to design a system that automated, and improved upon the existing design of a rotating spice dispenser. Ways that we sought to improve that design was automating both rotation and dispensing, and the ability to dispense small measurements of the chosen ingredient. We thought this would be both interesting and useful because often when changing the portions of a recipe smaller, and oftentimes odd measurements are required. We also believed if time allowed we could add functionality for pre programmed combinations/recipes.
The automated spice dispenser idea and design we chose was intended to help those who like to cook but may need to change the portions of recipes often, as well as people who often cooked with unique spice mixtures. A good example of the former group would be college students cooking a meal for only themselves, which may have instead originally been intended for a group.
Originally we tested a prototype design that would dispense based on volume. After testing we found that this style was easily prone to binding or letting spices in between the rotating surface and static surface causing issues. This also ruled out a similar design we had come up with that was also based on a fixed volume being dispensed but instead of rotation would use a sliding plate. After testing these designs I primarily worked on testing the electronics that we would be using. I also helped my teammates learn about and worked on the code for the system, and the assembly of the electronics. I also had some basic practical experience with using a lathe and mill to make simple parts.
Left: The wiring for all of the conectors that tie the ESP32 to the other components.
Right: The top side layout of headers that the wires are conecting, and the socket for the ESP32.
Left: All of the boards and components being assembled and connected.
Right: The mount and support for the load cells that I machined using the mill.
Our design uses a removable 6 compartment system that ensures we both had multiple spices as well as allowed for easy cleaning. It also uses two stepper motors, one for rotating the dispenser to the correct position based on the spice chosen, and the other for dispensing. The second stepper motor through directional bearing rotated augers which were responsible for dispensing the different spices. Augers were chosen because they would allow for a wider variety of spices to be compatible with the system. In addition I also tested how much power the system would use in different scenarios to ensure that we would be able to provide enough power.
Following this project from the beginning to the end we have learned that time estimates often included more aspects than we anticipated meaning that often we needed to put in more work to meet our goals. We also learned that it is better to have a functional product as soon as possible, because from there you can make significantly better informed decisions on what needs to be re-designed or approached differently, or what may need fine tuning to be reliable. If this system is re-approached a better control scheme is necessary. The mounting points for all mechanical power transmition should be done with better accuracy and precision as well as being stronger. A solution to the micro controller not functioning without first being started on USB is needed(possible due to cheap hardware). And dispenser tolerances should be moved to either tighter or looser extremes to allow for better reliability when dispensing(possibly higher resolution 3d printing). Designing out the stepper motors should also be possible as they were used for the convenience of simple control of distance, direction, and speed of motion.
Two nema 17 stepper motors
Two tb6600 stepper drivers
Two OLED displays
An ESP32
Two 200g load cells