SENIOR CITIZEN GARDENING CARTSept 2019 - Mar 2020 | Gardien Products | Senior Mechanical Engineering Capstone
BACKGROUNDGardien is a gardening product company that designs, manufactures, sources, and distributes gardening products, and seeks to disrupt the market and stand out among competitors with the products they make. They were looking to create a new product in the gardening space.
PROJECT OVERVIEWThrough competitive product analysis, IP research, and user interviews, our team determined there was a white space for a gardening tool that made gardening more accessible to older users who experience joint pain and trouble getting up and down. We created a lightweight, collapsible, dual seat and kneeler that has handles to aid standing and sitting, the ability to rotate for increased range of motion, and tool storage for easy access to tools.
PROTOTYPINGVERSION 1
After defining our needs and specs from user interviews and client meetings, our team started the process of ideation and prototyping. We went through three rounds of designing, prototyping, and testing before coming to a final design. Each iteration was meant to directly test one or more of out specifications, and built on results from the past user testing.
For the first design iteration, I worked on a tripod concept aiming to meet the needs of compact storage and ease of movement. I created CAD, 3D printed the connection points and sliders, cut tubes, and used good old super glue to create this prototype. Unfortunately, this prototype failed before we could test it with users, but I learned the importance of determining the correct materials for your desired use.
TESTINGOur team went to Three Crowns Park retirement community, and met with five women ages 75-85 for user testing. Our biggest takeaways were the needs to ensure stability and create high enough fidelity prototypes so users could properly test and comment on them. Other takeaways were that we needed to determine an acceptable range of heights for the product, the cart should not get in the way of users legs when they are gardening, and that the cart should be light enough to be moved by all users.
PROTOTYPINGVERSION 2
While we got a lot of useful feedback in terms of what users want from a product, the prototypes were all over the place because we did not outline what we actually wanted them to test. In order to maximize the effectiveness of our prototyping, we picked what needs we wanted to specifically test and use them to guide our designs. Choosing only a few features to incorporate into our designs allowed us to discover how important certain features were based on users comments on what was there, and their questions about what wasn’t.These prototypes focused on testing users responses to kneeling vs. sitting, material, collapsibility, movement, and range of motion.
TESTINGFor this iteration of testing, we created a standardized user testing guide and were able to test over 30 users including more people from the retirement community, Northwestern students and faculty, family, and neighbors. Our biggest takeaways from this round of prototyping were that users valued whether a product “looked” like it should be in a garden (colors/materiality), did not want something that was too large that it became unwieldy, did not want a product to move or rotate unexpectedly, and chose to sit or kneel based on where they were gardening (the ground vs. raised bed).
During these testing sessions, I would see users fiddling with something or attempting to use a prototype in a certain way, and would ask them what they were thinking about while doing that which led to them giving really great feedback that they weren’t saying because they didn’t think it was important enough. I also noticed discrepancies between what people said and what we observed them doing. For example one users “easy” solution to moving tools around was a shopping cart that she had difficulty moving and taking things out of. Making sure to observe what the user is doing in their environment rather than just taking their word for it helped me learn more about the user and better understand the design problems we were facing.
PROTOTYPINGVERSION 3
By using our prototypes purposefully to test certain questions or needs, we were able to focus our design scope and create two new prototypes that tested and asked more specific questions. Our two new prototypes incorporated materiality, size, and collapsibility that users had responded positively too, and were made to test if users needed the cart to allow rolling movement, kneeling, and handles.
I led the manufacturing for the rotating seat and kneeler, and fabricated the adjustable handles and rotating component. I bent and milled telescoping tubes to create the and fitted them with a button pin for adjustability. For the rotating mechanism, rather than just having a free spinning bearing, I designed and 3D printed a locking mechanism that comprised of a ring of teeth and handle with a notch that when pulled forward meshed between the teeth and stopped rotation.
TESTINGThis round of testing showed our team that we had deviated slightly from original design goals and user feedback. A majority of the 20 users we tested with despised the lack of handles on one prototype and the number of steps needed to deploy the legs on the other. This along with load failures brought the team back to our original needs and specifications to help refocus for the final prototype.
To help better understand and analyze of the massive amount of user testing data we had collected, I coded the results of user testing for each prototype into two tables: one that determined the polarity of a category by taking the difference between the positive and negative comments of a category, and one that kept track of the separate sentiments towards the cart and tallied the total number of positive and negative responses for each category. From these charts, we were able to see aspects users had consistently liked, disliked, and wanted across prototypes to know what to incorporate into our final design.
COMPONENTSFINAL DESIGN
The final design is a two part seat and kneeler that allows for easy collapsibility and storage, both sitting and kneeling configurations, easy to grip handles and knob, and aid for a user in lowering themself down and standing back up. It consists of four subsystems: a folding frame, rotating mechanism and stop, connection element, and handles.
Notable changes from the last design are detachability, x-frame collapsible legs, handle shape and collapsibility, and a spring loaded knob that keeps the rotating mechanism in a default locked position until it is pushed. For this design iteration, I created full system CAD, 3D printed the connection element, cut, milled, and assembled the folding frame and the seat. The team also completed engineering analysis calculations to determine if our final design would meet our specifications for load bearing and applied torque.
FINAL PROTOTYPE PROGRESSDuring our final few weeks of the quarter, COVID-19 pandemic struck the United States. The team continued building on our final prototype right up until we were told we weren’t allowed to use university facilities and a shelter-at-home order was put in place. Because of this progress was halted, but the team developed performance testing guides for Gardien to be used to validate the outlined specifications before the product can go to market.
