HCDE 451 A1: Model Prototype

Pet-Grooming Appliance

Sami Foell
4 min readOct 11, 2023
Image 1: Pet-grooming appliance prototype


Product Scoping

Looking over the product options for this assignment, the choice to create a pet-grooming device caught my eye. The combination of both digital and physical affordances required, from modular grooming attachments to a digital sounds interface, and necessary incorporation of OXO product design language posed an dynamic prototyping challenge to tackle.

Image 2: Product Backlog + OXO Design Language

I created a backlog of design requirements from the assignment description to provide a solid guide as I continued forward. An exploration of the OXO website allowed me to uncover insights into themes in product design (e.g. simple, comfortable) that could be implemented down the line. These preliminary stepping stones provided me with a launching point into my iterative prototyping phase.


Initial Sketching

Keeping the OXO design language and assignment design requirements in mind, I hopped into my sketchbook with my ink pen to begin externalizing my ideas. This processes began as mainly generative, with the goal to get a wide variety of sketches of how the device would look, what inputs could be utilized (e.g. button or slider), how product components could be sized, and potential interaction point hierarchy.

Image 3: Initial Product Sketching With Dimensions

After this generative phase, I narrowed in on several sketched product components that I felt best balanced the necessary product requirements for the assignment, but also would provide an intuitive, enjoyable, and low effort experience for pet owners using the grooming tool. (I decided to add a new feature as well, a pet treat dispenser!).

Cardboard Prototyping

Having a focused design idea to hone in on, I headed to my garage to grab some old Amazon shipping boxes along with my box cutter, hot glue gun, ruler, cutting mat, and no. 2 pencil. From there, I dove right into carboard prototyping!

After some time of tedious cardboard cutting and several sticks of hot glue later, I created the following low-fidelity, interactive prototype of a pet-grooming tool:

Pet Grooming Base

Image 4: Cardboard Prototype

Notice the usage of smooth corner radii and usage of rounded, flush, and minimal components throughout. This was intentional to stay inline with OXO design language (along with inclusion of the OXO logo). The input hierarchy of ‘Power Button’, ‘Speed Slider’, and finally ‘Sound Interface’ enables the most crucial interactive points (e.g. device power) to be the most easily accessible with a single hand grip of the tool. Having distinct input sizes and types (i.e. a large circular button for device power and a vertical slider for device speed) saves users the cognitive load of differentiating between many similar input points (i.e. buttons). The large size and close spacing of interactive components affords greater speed of target acquirement (Fitts’s Law). The treat dispenser is located on the back of the device given its lower necessity within the product use context but also it’s position as the ergonomic ‘hilt’ of the device.

Pet Grooming Attachments

The prototype is fully modular, with four potential attachments for users to insert into the top of the device.

Image 5: Pet Grooming Attachments


User Testing

In order to uncover any potential usability pitfalls and areas of improvement, I conducted one round of user testing. The participant was given a context and task to traverse through, evaluated via success criteria. Post-test, they were asked how their experience was, if anything was confusing or surprising, and if they appreicated about the product. See the video below for details.

Overall, the user test gave me insight into product desirability and usability. Giving them a usage scenario and a prop allowed them to have a sense of purpose and direction during the session. Allowing them to refer back to the prompt allowed the test to flow more seamlessly, though in hindsight the task may have been too long and should have been divided into several. Though the participant was able to successfully navigate through the task and meet all success criteria, they indicated concern at the absence of a label on the speed slider. This was added in the final prototype iteration. Overall, the test indicated this protype was very straightforward and easily navigable, allowing users to successful achieve their pet grooming goals with low interaction cost (i.e. physical and mental effort).

Design Critique

The in-class critique enabled me to gain more ‘expert’ insight into my prototype. Key opportunity areas from this session are outlined below:

  • Treat container opening and tab is quite small, posing a slight challenge for users to open without some effort.
  • Consider using a soft-cornered rectangular base instead of a cylindrical base to better synchronize with OXO design patterns.
  • Decrease height of product attachments to better align with height requirements (e.g. pet massager)

Overall the critique allowed me to gain greater insight into improvement areas for this prototype, giving a solid direction for future work.