Racquet Pro

A multi-channel application that helps tennis players analyze their performance through data.


Gabriel Castro (Me)
Kennedy DeSousa
Alekya Goli
Valerie Kolb


UX Design
User Testing




Sep 2022 - Nov 2022


This project was designed over the course of ten weeks during the Fall 2022 quarter in the HCI program at DePaul University. The goal was to understand the prototyping and implementation process by designing a product that works across multiple devices. The solution we came up with was a smart tennis racquet attachment that worked alongside a mobile and smartwatch application to support a tennis player's goal to improve.

Having never played tennis before, I was excited to design a product for a subject area and a target audience I was unfamiliar with.

Project Description

Racquet Pro is a smart tennis racquet attachment that works alongside a mobile and smartwatch application to help tennis players visualize, analyze, and identify areas to improve beyond the scoreboard. It allows players to measure their skills and improve their performance through goal-oriented training.

The project's goal was to design a multi-channel application for players to use during training, allowing players to identify areas to improve through data visualization.

My Contribution

My focus was designing for the user task for evaluating performance and identifying areas to improve. This included ideation, prototyping, and usability testing of my performance and insights sections of both the mobile and smartwatch app.

I also developed the full report from our usability test.

Understanding the Problem


In tennis there are no measurements of performance other than what appears on the scoreboard. It is easy to understand that a player needs to improve when they lose. But how can a player know what they need to work on without another set of eyes to watch them? There is much more that goes into a player’s performance than what shows up on the scoreboard that measuring a player’s technique can reveal.

How might we identify how to improve in a game where personal performance is ambiguous?

  1. Work cohesively with multiple devices
  2. Be non-intrusive to the user’s training session
  3. Allow users to record and measure their performance during training
  4. Provide a way for users to analyze, evaluate and identify areas to improve their performance



We identified two target users. These two users represent the beginning player learning the techniques of tennis and the advanced player looking for an unbiased view of their performance. We believe their level of experience influences their needs, motivations, and pain points.

From these personas, we were able to develop a general user journey for each type of user. This helped us develop the paper prototypes for user testing.

Competitor Research

Direct competitors would be the Sony Play Sensor, the Babolat Pop, and the Qlipp Sensor. We found that the majority of smart sensor devices for tennis were single-channel devices. A multi-channel application that combines a sensor, a wearable device, and a mobile application could provide a unique value to the user.

Looking at the current market provided interesting insights into these devices.

Design Process


Based on the goals and pain points found in our personas, we collaborated in a design charrette to brainstorm the features of the product. This helped us rapidly ideate various potential designs of the product. We were able to communicate our abstract ideas and bring them closer to conception.

Low fidelity sketches

Once we came to an agreement on the design of the applications, we moved on to implementing an interactive and testable prototype. This helped us bring the product into the eyes of our users for feedback.

Mobile wireframe image
Watch wireframe image
Usability Testing

We tested our prototype with eight users of varying tennis expertise. From our tests, we were able to identify common themes from our prototype

Confusing navigation

There were no indicators for navigation.

There was no way to navigate through smartwatch.

There was confusion about the difference between swing data and session summary feature.

Inconsistent visuals

Each screen felt like a different app.

The prototype did not look like the device.

The way screens with multiple pages were indicated was inconsistent.

Unclear labels

Labels for menus and navigation bar were unclear.

The communication of tabs was unclear.

The function of the profile section was unclear.

Final Design

From the pain points and themes found during our testing, we were able to move towards a final design iteration.

Record training sessions and swings in real-time

Training sessions can be recorded, and each new swing can be measured in real-time.

To improve visual consistency fonts, buttons, and symbols were standardized. A color palette and logo were standardized.

Evaluate performance and identify improvements

Player performance can be measured and analyzed to help give players a new perspective on their play. Insights can help visualize statistics and offer players tips on how to improve.

To improve the distinction of this feature, we decided to change this from an end-of-session summary to the player's performance summary. This allows users to review their performance as a whole.

Freedom to control

Users can control the recording of their sessions without having to go back to their phone.

To improve navigation of the smartwatch, we added a homepage that users can use to navigate to all features.

Review training measurements

Training measurements can be reviewed at the end of the session from the watch.

To improve communication of tabs, the consistency of new pages was designed to be consistent for all features.


Emphasize the need for more user research

Because the course was focused on the prototyping and implementation of a product, there was less emphasis on user research. I found that when it came to designing the product, we struggled finding solutions for things like information architecture, content strategy, and user-task analysis. This became problematic for us because it forced us to make a lot of assumptions about our users. 

First answer the “WHY", then the “HOW”

There were many times where I found myself trying to find a solution before understanding the problem. When it came to prototyping the interface, it became difficult to understand how to implement certain features. Understanding the user goals would have provided a better foundation.

Strong communication and standardize design with team

Because this project was done remotely and all team members lived in different time zones, it was difficult to find time to work concurrently with others. This led to each of our features having vastly different visual aesthetics. This highlighted some of the difficulties while working with other designers. I believe building a stronger base of communication and standardizing design decisions would have helped us design a cohesive product.

Test and iterate and test and iterate…

We still got valuable information from our usability test. Had we had more time to test more design iterations, I believe we would have gotten even closer to a more well-rounded product.

Improve visual design skills

This is the area where I want to improve the most. I found myself getting lost in the design decisions like choosing font styles, color palettes, and visual aesthetics. Though I am proud of what I accomplished, I am not completely satisfied with how the product is. It became clear that this is an area that I could use the most practice in.