Model Prototyping: A Shower Valve (A2)

Design: The OXO brand aims to design everyday objects to make life easier through universal design. Their products include features like ergonomic grips, being easily gripped with both hands, and intuitive to use without a manual. When designing this shower valve, I wanted to make it accessible for people that had trouble gripping and impaired vision. In the shower, if you aren’t wearing corrective lenses it can be difficult to see the controls for an advanced shower valve. Therefore, the shower valve should clearly display each function and have distinct tactile feedback so that if visibility is really impaired, you can use touch to select the proper controls.

Most shower valves have a lever or knob to turn on the shower, control pressure, and temperature. Since the lever would obstruct the digital display, I thought about a knob. I researched products designed for people with arthritis and found these door knob grip attachments. I used this “tear drop” shape for the main control knob.

For the digital display, I wanted to keep it simple and with visually distinct elements so you could still see it in the shower. I displayed the temperature’s numerical value and the pressure as a bar. I chose the bar because typically we turn on the shower, then adjust the pressure to be less or more and I felt the bar was a good way for someone to adjust the current pressure relative to where they wanted it to be.

The front view of the shower valve
Close-up view of the main shower valve
Switches on the side to control which spout the water exits from
Backside of the prototype

Prototype: The main platform for the shower valve was built using cut outs of foam board strips to create a box. The shower valve was cut using another piece of foam board and glued (with liquid glue) between two pieces of fountain pen paper. To secure the main water control to the platform, I punctured two holes and threaded a bobby pin so that it could spin like a typical shower control. The switches on the side were made using small binder clips. On the handle of the binder clip, I inserted different colored labeled pencil grips to represent each type of water spout. The pressure/volume bar is displayed using a folded post it note that is moved behind the platform.

Some downsides of these materials were:

  • Foam board is really difficult to cut neatly with scissors and even a small kitchen knife (notice the jagged edges of the platform).
  • Bobby pins are secure, but don’t slide easily which I wanted my prototype to do for the shower’s pressure adjustment.
  • I wanted the remaining switches to flip down when one switch was activated, but I found it difficult to replicate with just the binder clips.
  • The post-it note taped behind and moved was difficult to coordinate because there wasn’t a lot of space in the back to shift the components.

Testing Analysis: I performed one usability test (see video). I asked the user to turn on the shower, to increase the volume, then to switch the water from the shower to the bath tub faucet. Some usability issues I noticed were:

  • The directions for hot/cold were confusing. My intended design was for turning the knob right to increase the temperature, but my friend who was performing the usability test turned it left. I realized afterwards that the vast majority of showers turn on by twisting to the left, so in a future iteration I would need to flip the red/blue labels and the valve so that the concave side would be on the left.
  • The sliding temperature strip and volume bar were difficult to move without obstructing the the user interacting with the prototype. In the future, I would put the prototype on a larger board to represent the shower wall to hide the inner workings.
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