A2: Low Fidelity 3D — Studfinder

For this project we were asked to create a low-fidelity 3-D prototype using basic materials such as cardboard, foam, etc. The task was to redesign a wall stud finder that could comfortably be used in both hands and held at different angles.


I knew that wall stud finders had traditionally very flat surfaces and box-like in structure. After googling some of the more popular wall stud finders it was apparent that most of them emphasized on just holding the stud finder by two contact points. I wanted to eliminate that and create something that engaged the entire hand to comfortably hold the device against the wall so that it didn’t require all of the work to be done at two points.

Here are my initial sketches:

Process is from right to left

From my sketches you can see how I immediately started to deviate from the box look and headed towards more curved shapes for the body of the stud finder. I wanted it to be more ergonomic and have more contact points with the hand that would use it. In the beginning I designed it to have part of the body rest on the hand between the thumb and pointer finger. I also drew some ideas of grips on the sides of the device.


I constructed my first prototype out of foam and after some user-testing I realized that the user didn’t really know how to hold it because of all of the different curves. This led to the second prototype that I made out of a old butter box, part of a shoe horn, and rubber bands. I pieced things together quickly with a hot glue gun.

Top Pictures: construction of the main body. / Bottom Pictures: Adding Rubber bands to the sides for grip

The shoe horn served as a protruding piece that would force the user to make contact with it using their palm and it would help guide their hand to orient itself more consistently. Also the rubber bands on the sides were strategically placed as affordances for the fingers. The area of the rubber band grip was designed to accommodate both left and right hand users of the stud finder. One piece of the prototype that is not shown are the pennies that I used to give the actual prototype some weight, which also changed the way that the users decided to hold the finder.

Here are some close ups of the finished prototype:

Top left: The full assembly is able to stand upright because of the penny weights. / Top right: Detailing of the rubber band grip.
Bottom left: interface of the finder that displays calibration. / Bottom right: the stud finder with the flash light


I tested this prototype by creating a fake scenario where the user would need to find and mark studs in dry wall. I accomplished this scenario by marking clear tape with “studs” and inserted a flash light in the body of the prototype to emulate the laser that would signify the existence of a stud.

The tasks were:
1. Hold the stud finder against the wall 
2. Calibrate the stud finder 
3. Scan the wall with the stud finder
4. Mark where the studs are

What worked well:
I think that the best part of my prototype was the shape and also the grip that was placed on the side of the box. The users that tested the stud finder remarked that the device fit well in their hand because “it felt natural, almost like a computer mouse.” The user also said that the grips were helpful and let her know where to place her pointer finger when grabbing the device. Also I think that the penny weights made a huge difference because in a way it forced the user to hold the device in a certain way instead of a light prototype that could be effectively held in way more different directions. The user was able to pick up the device and scan the wall for the “studs” pretty fast and accurately with one hand using the stud finder and the other using a pencil.

What needed Improvement:
The number one thing that really stood out to me was the calibration portion and affordance of the device for calibration. As shown earlier, the device was made up of a shoe horn attached to a butter carton. The top part of the shoe horn that sticks out from the device was intended to be a touch pad that could be tapped to calibrate and held to turn off and on. However, it didn’t seem the easiest for users to do that with one hand. Also I feel like the interface of the device was weak and static. It didn’t seem like it was much use to the user and that the light was more intriguing and guiding for the tasks given.

I would say that this low-fidelity prototype was a good exploration of creating a very useful and life-like tool with limited or low-quality materials. I was able to get shapes and create features/affordances that I would not have been able to do with a paper prototype. Of course the task was different and it was more industrial yet the interactions and tests were unique and offered great insights to designing something like this.

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