Our final prototype was a success in some ways and still a work in progress in others.
On the mechanical front, the linkage assemblies were successfully manufactured and implemented in the prototype to allow for a smooth motion in the lid. As there were two configurations built into the sides of the full prototype assembly, any forces that acted normal to the plane of motion would not affect the functionality or integrity of the mechanism. All bearings and pegs were press-fit, and the axles of the step-motors were press fit into the custom-built interface on Linkage 3. Furthermore, the custom-printed step motor mount kept the step-motor in place. The exterior wooden box is sturdy and robust, so that it can take minor impacts and forces expected from a pet eating from a bowl inside. Finally, the wooden restraint pieces built into the exterior wooden box are able to restrain the movement of the interior box, protecting the integrity of the motor mounts, internal wiring, and linkage assemblies. As such, from a mechanical standpoint, the prototype was certainly a success.
On the electrical front, the RFID and ultrasonic sensors functioned to our expectations. After running tests, the RFID sensor was able to distinguish between two different RFID tags, and successfully reported whether access was granted or denied, accordingly. Further, the close command was initiated only after the ultrasonic sensor detected a range between the pet and itself being greater than 30 cm. The only issue we had was the motor selection, as the stepper motors did not have enough torque to lift the lid and acrylic window assembly. Furthermore, it was unfortunate that both stepper motors could not initiate a rotation at the same time, rather they had to be operated one at a time.
Key Takeaways:
- We jumped the gun with manufacturing and assembly, and therefore experienced multiple integration issues with the final product. The key takeaway here is that we need to finalize the CAD, including electronics, before beginning manufacturing and assembly.
- We tried to make a very professional product from the beginning, although we should have realized that prototypes do not necessarily need to look nice.
- Although a full semester has been allotted for the project, considering the delays in procurements and multiple last minute changes, we had roughly a week for final assembly. In the future we need to a lot more time for design.