Design:
Continuing the design concept from Parcel Locker, I decided to create a CAD 3D model of the lock box so I could get a more precise representation of the concept.
For a quick recap, Parcel Locker is a lock box placed in front of your door where deliveries can be safely deposited and locked until you’re ready to retrieve them. For more details, the original prototyping blog can be found here.
After the previous low fidelity prototype, I received a concern about small pets or wild animals accidentally being shut inside the lock box. However after surveying a larger audience about this issue, I came to the conclusion that 1) this is very unlikely because the window of time an animal would be able to jump in (either during package deposit or package retrieval) is extremely short and 2) if an animal were to get trapped in the box, a delivery personnel could scan their code to open the box, or the lock box owner could unlock with their personal device to let the animal out.
With this decision made, I decided to keep my previous design and begin my CAD model using OnShape.
Prototype:
Building the previous analog 3D prototype was extremely helpful in the first step of this CAD 3D prototype — breaking down the build of Parcel Locker. The previous cardboard prototype allowed me to visualize the 4 main components of this design:
1) the main box, 2) the barcode scanner, 3) the camera, and 4) the lid.
With this in mind, I started on the main compartment. First I measured my previous cardboard prototype to get the length, width, and height for the main compartment and put that into OnShape. Next, I knew I wanted the finished product to be made of metal and to minimize sharp edges and injuries, I rounded all the corners of the box.
Then I moved onto the scanner and camera. I wanted these pieces built into the main compartment so I selected the front of the main compartment as my building face. I created a rectangle for the scanner, again with rounded edges. I made the scanner stick out from the main compartment just slightly so that it would be easier to spot for the delivery personnel during use and gives the product more dimension. Next, I build the camera. I made this a half sphere so that the camera would have a full 180 degree view. I also put it near the top of the main compartment since that’s where a potential thief would be looking.
Lastly, I build the lid to the box. I wanted it to fit perfectly on top of the main compartment so I first built a general shape slightly longer and wider than the main compartment. I then used the boolean extract feature to remove the exact shape of the main compartment from the lid to create a perfect fit.
With all the pieces assembled, the finished CAD 3D prototype:
Analysis:
I hadn’t done any CAD design in about 3 years so jumping into OnShape was both easy and difficult. Doing simple procedures like sketch or extrude was easy but remembering how to make new faces, managing the different faces and angles, making sure all the measurements were confined took a little bit of getting used to. Originally, I wanted to make a hinge for the lid but after watching and attempting to follow along a few tutorials, I determined it would take too much time for me to learn and produce a working hinge for a low-fidelity prototype. If I had more extensive knowledge in CAD or more time to spend on this iteration, I definitely would have liked to trial different types of hinges.
