HCDE 451 A2: 3D Model Prototype of A Pet-Grooming Appliance

Michelle (Xin) Gao
9 min readOct 14, 2019


“We look at everyday objects and activities and we see ways to make things simpler, easier, more thoughtfully designed — better.” — OXO

the redesigned voting machine

In this week’s studio, we practiced our rapid prototyping skills through an activity aimed at redesigning the voting machine. Through this exercise, I learned how to creatively use the limited resources to build a low fidelity prototype which still captures all the core competencies of the product.

Design for This Week

The design for this week is to prototype a pet-grooming appliance as if it was made by the company OXO, a company aims to make people’s lives simpler and easier.

The specifications for the pet-grooming appliance are as follows. It should include:

  • A Brush component that allows for all-over fur brushing
  • A comb for fine-grained de-matting
  • A rotary tool (similar to a Dremel) for claws to be filed
  • A vibrating component that allows for massage
  • A digital display for playing 5 different soothing music
  • The nail filer and the massagers must be able to turn on and off and choose from 3 speeds

Idea Sketching

Living with pets, there’s no doubt you will face a home filled with pet hair, paw scratches, and a whole list of other issues that can drive you crazy. Therefore, for the sake of convenience, instead of addressing these problems individually, I think an ideal appliance would be an all-in-one pet brush, nail filer, and pet massager.

I searched some of the popular pet-grooming appliances on Amazon and it seems that most of the appliances serve only one main function. For example, one of the most rated appliances is a de-shedding brush. It is a great product, but it only serves one function. Thus, to echo with the company’s brand which to “find ways to make things simpler and easier”, I put the “all-in-one” idea in my mind and wanted to create something that included multiple functions so that it didn’t require all the works to be done in multiple times.

Before I started, I always liked to create a checkbox list for all the specifications in case I missed anything important and it was easy for me to check reference by using this list. I researched the different pet grooming appliances with their corresponding features and drew down their most popular design for inspiration purposes. For example, I found out there are two different types of pet brushes, one is the long pins brush for losing the fur and the other one is the bristle brush which is used to lift excess shedding and dander. Thus, I came up with improvements that making the brush has both long pins and bristles on different sides so that users can lose the pet’s fur and lift excess dander in a roll.

Design Checklist for the Pet Grooming Appliance
Design checklist for a pet grooming appliance

To include all the features, I chose to make the components of the device to be modular with one main body part (the handle) — for example, the user can detach the brush head from the handle to add on the comb. Here are the different sketches for the heads:

Sketches of different detachable heads

My idea for this pet grooming appliance was that it should include a handle and four detachable heads — a brush head, a de-matting removal, a rotary file grinder, and a vibrating massage head.

Handle Design: Handle design is tricky because you need to be aware of not to make the handle too thin, too big, too stiff, or awkwardly shaped. And also because individuals vary in how they grip according to their habit(left/right hand)and hand size. Therefore, when I designed the handle, I need it to secure against accidental sliding and unwanted twist because this appliance would be used on our lovely furry friends. From the above sketches, you can see how I headed towards a curved shape (similar to the bowling pin)for the holding part. I wanted the handle to have more contact points with the hands and at the same time, user-friendly to both left or right-hand users. A curved shape like that would help me achieve these two goals. To add more fraction, two-piece of silicon patches would adhere to each side.

Digital Display and Button Design: I placed the digital screen at the top of the handle and the buttons right below the screen, where it would be easy for users to view and manipulate. The three buttons were placed in a triangular shape where the on/off button sited on the top and the ➕/➖buttons sited below. The ➕/➖buttons were designed to let users change speed levels and modes. On the bottom part of the handle, there would be three light indicators designed to show users which mode they are on now.

Different Heads Design: Design for each head was fairly simple because each of them has its conventional design and what I did is to make improvements in some details. For the brush head, I planned to make a two sides brush which has long pins on one side and bristles on the other side and added some minor details such as putting the rubber beads on the top of the pins to prevent skin scratch. While designing the de-matting removal, nail filer, and the massage head, I used their conventional designs as references.

Lastly, for the detachable nature of the device, this idea came from my personal satisfying user experience with my Philip Electric toothbrushes. I like how simple the pull-out movement required for replacing the head. And since the tool will be immersed in pet’s fur most of the time, I thought the detachable design should be easier for users to clean up.

With all the sketches were done, I started to build my prototype for testing.


Materials and tools: sponge foam, papers, craft rolls, ping-pong balls, strews, cotton bars, tape, electrical tape, glue gun, and scissors.

The material used for making the nail filer
The material used for making the brush

I made prototypes for the nail filer, the brush, and the handle.

Overview of three prototypes

The main body — the handle, was built out of a half paper towel roll covered by a blank sheet of paper, a blue strew, several sheets of color paper, and a sponge foam. I first cut the paper towel roll to an appropriate length and then covered it with a white paper to make it more visually appealing. I was frustrated because I couldn’t squeeze the sides curved to the shapes as I expected and I couldn’t find a better material to replace it at the point, so with frustration, I decided to give up my curved shape and went with the cylinder. Then I need to build the connecting part between the handle and heads.

Connecting part

To make sure the strew can stand in the middle of the cylinder handle without sliding down, I made a sponge holder. I used the glue gun to burn a hole (smaller than the strew’s diameter) on the center of the holder to let the strew passed through. This holder not only tightly hold the strew but also help me seal the top. The body was almost down and what I need to do next was just some simple paper cutting works. Light blue and light yellow were the color I picked for making the silicon patches and buttons. While making the buttons, I added some sponge under each button to give that tactile feeling. Lastly, I drew three light indicators for three different modes (Nail, Massage, and Sound)in pencil and then, I was done with the handle!

Left: the rotary nail filer head; Right: the brush head

The next step was to make the heads. To make the nail filer, I sacrificed my ping-pong balls :( I cut the balls into half and then drilled a hole in the center for letting the strew pass through. I used the black electric tape to hide part of the strew and also to give it a mechanistic approach. A cylinder sponge foam was added to the top to replicate the sanding drum. For the brush head, I used the sponge foam as the base and covered it by the white paper. The sponge base allowed me to insert the sticks that I cut from the cotton bars. (*I didn’t make the other side with bristle because I couldn’t find any material to replicate the texture of the bristle.) Last but not least, to prevent skin scratch, I dripped several drops of hot glue on the tips of the stick to replicate the rubber beads that I used to see on my hairbrush.

Left: Brush head with the handle; Right: Nail filer with the handle

Some upsides/downsides of these materials were:

  • Paper towel roll was easy to cut but didn’t allow me to change shape.
  • Sponge foam can be used as the place holder because of its squeezable nature.
  • It was a really bad idea to apply hot glue on the sponge foam because it would release a repugnant smell and the foam would melt quickly due to the high temperature.

Testing Analysis

After finished the prototypes, I tested these prototypes with a fake scenario where the user needed to perform tasks that correspond to each feature. I first asked the tester to turn on the tool and change to the “Nail” mode, to file the unicorn’s horn, to increase speed level, and then turn off. Then I asked the tester to detach the filer and put on the brush. Here is the demo video:

Critiques received from the fellows

What needed improvements:

  • Users got confused with the buttons and didn’t know that the ➕/➖buttons could also be used to change modes.
  • Users reflected that the handle was too long to apply force on it. This issue was more obvious when the tool was used as a brush.
  • Change the placement of the screen because it would be partially covered by users’ hands when they were holding it.
  • Change the placement of the buttons because users would accidentally touch the buttons when they didn’t intend to.

It was not a wise idea to use only one button to control two different functions, even though I save some space but ended up generating more confusion. I need to add one more button for only changing the modes. I might also get rid of the light indicators and move both the screen and buttons lower to avoid coverage and unwilling touch.

What worked well:

  • The modular design is intuitive and the way how I designed the connecting part was creative and easy to use.
  • The use of light yellow and light blue colors made the users feel very hygienic.
  • Users like the touch of the glue beads on the brush tips.


After this project, I realize how important to pay attention to the detail even when we were making a low-fidelity prototype because users have sharper eyes than we think. I wasn’t expecting the users to notice the beads on the tips because they were small and transparent, but they did notice and love it.



Michelle (Xin) Gao

UX Research and Design | UW HCDE Alumna | Class of 2021 @ UW MHCI + D