Why some products, or tools, are difficult to use? — Case Study: A Bluetooth speaker

Good design, when it’s done well, becomes invisible. It’s only when it’s done poorly that we notice it.

Project Details


November 2016 – January 2017

Type of Research


Methods & Skills

  • Think Aloud
  • Usability Testing
  • Business Model Canvas


  • Pen & paper
  • Video camera
  • Bluetooth speaker


Usability Testing Report

Business Model Canvas

Product Development

As part of 0HV100 Human Factors course, three other students and I had to identify examples of bad human factors design in our environments.

Background Problem

Examples of bad human factors are all around us. From confusing error messages on a computer screen to weird control configurations of your stove.

In this use case, the portable speaker can be used for listening to music and an FM radio. There are three main functions in the portable speaker: it can be used to listen to music from mobile phone via Bluetooth; it can be used to listen to music from mobile phone via a cable; and to listen to a radio.



Think Aloud study

We conducted a Think Aloud study while the participants had to perform several tasks using the Bluetooth speaker. This helped to generate verbal reports that indicated the usability problems of the speaker. The tasks consisted of a core task to listen to music and three peripheral tasks: via a Bluetooth connection, via a cable and using a radio channel.

Theory-driven Analysis

After a Think Aloud study was conducted, the video is transcribed and a theory-driven analysis was performed. The usability issue during the experiment was analyzed based on theoretical analysis of the underlying problem and possible solution based on Human Factor Principles.

There are three main problems using this portable speaker:

  1. The color between the label of features and the base color of the speaker is indistinguishable and can be considered as a bad human factors design. It is difficult to read even under the proper light.


2. The portable speaker also has only two buttons, namely ON/OFF button and volume slider. To change between the three main functions, people need to press the volume slider for few seconds and have to go through all the main functions. Most of the time, they always ended up increasing the volume instead of changing the feature.

3. The auditory feedback given by the portable speaker was not clearly understood.

Business Model Design

For each of these bad human factors design, we provided some solutions leading to an improved portable speaker. The new, improved speaker will have a universal design with three different buttons for each function, one button to switch to Bluetooth, one for radio and one for the cable connection. Each button is clearly labeled showing the function it provides. The speaker has additional buttons with a plus and minus side to control the volume. On the back of the speaker, a USB-port is located to charge the speaker. Above, a light display will indicate the battery level. In this way, the speaker doesn’t need auditory feedback. The speaker has a universal design allowing different types of devices to connect.

Value Proposition Canvas

The objective is to clarify the customer understanding and visualize what matters to customers.

Value Proposition Canvas

We identified customer jobs, gains, and pains. Based on this step, we prioritized their rankings.

Value Proposition rankings


Proposed Solution

The new Bluetooth speaker:

  • Small and lightweight
  • Radio function
  • Bluetooth
  • Hands-free calling
  • Waterproof
  • Separate buttons with clear labeling
  • And all that for … only €20




  • Identify examples of bad human factors design for a device/service/situation
  • Evaluated and analyzed the problems for improvement
  • Performed a usability test with a Think Aloud study and developed a theory-driven analysis
  • Evaluated the usability issues
  • Identified the theoretical analysis of the underlying problem
  • Provide possible solutions based on human factor principles
  • Provide ideas for solutions
  • Translated the solutions into a new product based on Business Model Canvas.