top of page
KRAMER DESIGN
Volt Smart Soccer Ball
Volt is a smart soccer ball designed for coaches to improve their immediate feedback to players. Use the Volt AI assistant to ask any question about how your team and players are performing. Volt also uses kinetic energy harvesting to make the balls self-charging.
Prototype
Commercial
Problem
It is difficult for high school and college-level coaches to track and stat-keep their players to help them develop. There are many schools around the country that struggle to hire and retain qualified assistant soccer coaches. Smart soccer balls also have to be charged frequently which is difficult for a large set of them.
Solution
Create a smart soccer ball that doubles as an AI assistant coach, with a feature to self-charge.
- Immediate feedback and stats
- Individual player screens with a comparison chart
-Player rankings
-Ball status screen (Air/Connectivity)
- Self-charging (Kinetic Energy Harvesting)
Field Research
I was able to work with the Women's soccer team at the University of Kansas to watch them practice, interview one of their players, and also do soccer drills with one of their coaches.
Practice Findings
- Lots of quickness drills
-About 30 balls on the field at a time when doing drills
- If the ball goes out of bounds, they just grab another one
- Ball stays close to the player's feet when dribbling
Interview Findings
-I interviewed with Jordan (Sophomore on the KU women's soccer team
-Said that the only way to see feedback was based on what the coaches saw and told her
- Said that it is hard to see small levels of progress from week to week
- Said that accuracy is probably the most important feedback.
Drill Findings
- The ball was heavier than I expected
- The ball moved differently in the rain
- It will be important to figure out the weight distribution with the sensor inside
- Balls get kicked out of bounds and lost very frequently in a drill setting
- Tony
- 58 years old
- Soccer Coach and Teacher
- Milwaukee, Wisconsin
Background and Context
He is not very good with technology, but wants to incorporate it into his practices. He would like an app to track stats from his team because it is hard to find reliable assistant coaches.
Pain Points and Frustration
He doesn't have a way to track his players without doing it manually. He also has struggles with other apps because they are confusing and have too much information.
Comparison
I researched three different smart soccer balls that were all for different purposes. Finding the pros and cons of these soccer balls allowed me to create a ball that solves all of the user's problems.
Adidas Trionda
This ball is the official ball for the 2026 World Cup and uses a side-mounted chip system. It provides real-time data, and it uses a 500 Hz IMU motion sensor. The triode sends data 500 times per second to identify the exact moment of every touch.
DribbleUp
This ball is the most prominent consumer-facing "Training Ball," and it uses computer vision technology with a mobile app to track movement. This ball uses an augmented reality (AR) interface where the phone camera tracks the balls design patterns and doesn't use any charging. The app has 1800 virtual training sessions and drills with real coaches
Adidas Trionda
This ball is the first ball with an integrated sensor to be FIFA Quality Pro Approved. It has an ultra-small tracking sensor suspended in the bladder that transmits data at 50 times a second. This ball uses goal line tech with copper wires to communicate with antennas in the goal line to confirm the ball crossed the line. It also has performance tracking to provide an overview of shot speed and pass quality
User Persona
Goals and Needs
His main goal is to see all of his players' stats after a practice. He has lots of players and would like to see an assessment of them each day to see areas that need work.
Behavior and Preferences
He would like an app with a clean interface and simple tasks. Having an easy way to learn and navigate the app is also very important.
Trends Matrix
I created a trends matrix in order to research some of the former, current, and emerging technologies that I could encorporate into my design.
Tech
Users
Color
Texture
Weight
Energy Source
Bluetooth sensors that tracked speed and spin. Only used for stationary kicks
Early adapters techies, hobbyists or individual players training solo with their phone
High contrast - traditional black and white with pentagons
Smooth or dimpled - basic "golf ball" dimples or standard smooth TPU to help with aero dynamics
Standard (410g - 450g) Traditional FiFA weight. Often felt heavy once sensors were added
Plugin charging - Balls had a hidden DC jack, making them heavy and prone to water damage
Formerly
500 Hz IMU and UWB sensors provide real-time data for VAR and semi automated offsides
Pro academys and refs. Also used by FIFA for officiating and elite clubs
National/Cultural branding, indescent finishes and tri-color ribbon patterns
Engineered skins - "Speed Shell" or 3D printed ink overlays; micro and macro grooves
Balanced "Zero Wing" - Sensors so small that htey are suspended in the center to maintain perfect balance and standard weight
Inductive (wireless charging) - Balls sit on a dedicated charging cradle or mat, similar to a smartphone
Currently
AI & Nanotech. Balls with on-ball AI processing and molecular-level sensors that track ball deformation and air pressure.
Grassroots/DIY - Accessible for smart education kits for schools with integrated social leaderboards
Adaptive/dynamic - Possible use of thermochronic or fluorescent materials that change color based on impact intensity or temperature
Haptic/self-healing - Biometric surfaces that mimic the "grip" of natural leather but are made of self-healing polymers to fix scuffs.
Variable density- materials that maintain FIFA weight but feel lighter on the foot due to high-rebound internal focusing
Kinetic energy harvesting - sensors powered by the motion of the ball itself eliminating the need for external charging entirely
Emerging
Concepts For Physical Object
- LED Timer Display
- Voice Assistance
- Panel Screens
- Wireless Charging Station
- Kinetic Energy Harvesting
Concepts For Interface
- Individual Player Analysis
- Recruitment help
- Charts to compare players on team
- Compare Athletes from differnt teams
- AI Assistant Coach
User Persona
He would like an app with a clean interface and simple tasks. Having an easy way to learn and navigate the app is also very important.
Behavior and Preferences
real-time data, and it uses a 500 Hz IMU motion sensor. The triode sends data 500 times per second to identify the exact moment of every touch.
DribbleUp
technology with a mobile app to track movement. This ball uses an augmented reality (AR) interface where the phone camera tracks the balls design patterns and doesn't use any charging. The app has 1800 virtual training sessions and drills with real coaches
Super iBall
small tracking sensor suspended in the bladder that transmits data at 50 times a second. This ball uses goal line tech with copper wires to communicate with antennas in the goal line to confirm the ball crossed the line. It also has performance tracking to provide an overview of shot speed and pass quality.
This ball is the official ball for the 2026 World Cup and uses a side-mounted chip system. It provides
This ball is the most prominent consumer-facing "Training Ball," and it uses computer vision
This ball is the first ball with an integrated sensor to be FIFA quality Pro Approved. It has an ultra-
Trends Matrix
I created a trends matrix in order to research some of the former, current, and emerging technologies that I could encorporate into my design.
Concepts
Physical Object
-LED Timer Display
-Voice Assistance
-Panel Screens
-Wireless Charging Station
-Kinetic Energy Harvesting
-Individual Player Analysis
-Recruitment Help
-Charts to compare players on their team
-Compare athletes from different teams
-AI assistant coach
Concepts For Interface
- Microfiber TPU + Thermal Bonding on the outer shell - saves 18- 27 g
- Thin TPU Bladder + UHMWPE Fabrics on the backing and bladder - saves 35-45 g
-Carbon Composite Shell + Titanium Springs on the core and springs - saves 9-14 g
Final Direction
After my extensive research I chose to design an app that comes with a built-in AI assistant, that has individual player screens to compare players stats. I also encorporated a self-charging feature using kinetic energy harvesting within the bladder of the ball to eliminate any energy source problems.
Stat Categories
The app tracks 6 different categories using a sensor that is suspended in the bladder of the ball. These categories provide rankings between the players on the team and appear in a comparison chart on the individual player screens. Coaches can ask the AI assistant about any other stats or questions about their team they may have. The AI assistant also suggests new drills to incorporate in practice based on the feedback from the ball.
Precision
Passing accuracy and sweet spot consistency
Power
Peak shot velocity and long-ball distance
Technique
Technique
Spin rate (RPM) on crosses or curved shots
Spin rate (RPM) on crosses or curved shots
Quickness
Release time (how long the ball stays at the player's feet).
Volume
Total touches or "time on ball" during a session.
Control
Quality of the first touch (how quickly the ball settles).
Kinetic Energy Harvesting
The use of kinetic energy harvesting is implemented by using copper wire over magnets so that when the ball moves it createsenergy that is then sent to the battery. This system is suspended in the bladder of the ball with springs to help with stability and balance.
Weight Distribution
Having electronics inside the bladder obviously adds weight so I broke down exactly how much it weights and how I could still keep the ball at the standard weight of the NCAA at 410-450g.
Micro Copper Coil & Neodymium Magnet - 18-22 grams
Converts kinetic energy from ball rotation/impact into electrical current
Solid-State / Lithium-Polymer Battery - 5-7 grams
Compact, ultra-lightweight rechargeable cell (50–100 mAh)
IMU / Bluetooth Low Energy (BLE) PCB - 4-6 grams
6-axis accelerometer/gyroscope, chip, and minimal circuitry
Shock-Absorbing Housing - 6-8 grams
Lightweight polycarbonate/silicone enclosure
Suspension Tether Harness - 3-5 grams
High-tensile elastomer strands securing the module
Total Electronics Weight - 36-48 grams
I also researched how to make the other materials lighter to accommadate for the electronics. There are multiple options that will keep the ball within the weight range.
Options For Lighter Materials
Lo-Fi Wireframes
I created initial wireframes as a starting point for my design.
User Testing
Doing a simple A/B form with 10 questions helped to fine tune my app. This helped me a lot with spacing and sizing of buttons. I found that less is more in this case. I was able to change the images of the balls and players and also change the weights of some outlines thinner and make them more subtle.
A/B Testing
I did usability testing for the app, in which I gave the user a task to complete. I learned that my AI swipe up was busy and hard to read. and that there needed to be black added to the text and outlines for readability.
Usability Testing
Final Design
The onboarding for this app starts by logging in, then connecting to your set. It provides instructions for how to connect the balls to your app and lights up green when connected. Following this, there is a set of instructions showing how to set up the RFID tag and start using your set.
Onboarding
Player Ranking Screens
The home page has a list of 6 categories in which the players are ranked. The coach can see an explanation of what these categories mean as well as click on individual players to see a comparison chart and other information about them.
The Volt AI assistant is a tool that helps coaches help their players. A coach can ask the assistant any question about their players that is not listed on the home page. After the coach receives this information, they can ask another question or request suggested drills.
AI Assistant
The ball vital screen shows the status of all the balls in your set. It tracks air pressure and connectivity and shows you how to fix it if there is a problem.
Ball Vital Screen
Quality of the first touch (how quickly the ball settles).
Having electronics inside the bladder obviously adds weight so I broke down exactly how much it weights and how I could still keep the ball at the standard weight of the NCAA at 410-450g.
Converts kinetic energy from ball rotation/impact into electrical current
Compact, ultra-lightweight rechargeable cell (50–100 mAh)
6-axis accelerometer/gyroscope, chip, and minimal circuitry
Lightweight polycarbonate/silicone enclosure
High-tensile elastomer strands securing the module
I also researched how to make the other materials lighter to accommadate for the electronics. There are multiple options that will keep the ball within the weight range.
- Microfiber TPU + Thermal Bonding on the outer shell
- saves 18- 27 g
- Thin TPU Bladder + UHMWPE Fabrics on the backing and bladder - saves 35-45 g
-Carbon Composite Shell + Titanium Springs on the core and springs - saves 9-14 g
Doing a simple A/B form with 10 questions helped to fine tune my app. This helped me a lot with spacing and sizing of buttons. I found that less is more in this case. I was able to change the images of the balls and players and also change the weights of some outlines thinner and make them more subtle.
I did usability testing for the app, in which I gave the user a task to complete. I learned that my AI swipe up was busy and hard to read. and that there needed to be black added to the text and outlines for readability.
The onboarding for this app starts by logging in, then connecting to your set. It provides instructions for how to connect the balls to your app and lights up green when connected. Following this, there is a set of instructions showing how to set up the RFID tag and start using your set.
The home page has a list of 6 categories in which the players are ranked. The coach can see an explanation of what these categories mean as well as click on individual players to see a comparison chart and other information about them.
The Volt AI assistant is a tool that helps coaches help their players. A coach can ask the assistant any question about their players that is not listed on the home page. After the coach receives this information, they can ask another question or request suggested drills.
The Volt AI assistant is a tool that helps coaches help their players. A coach can ask the assistant any question about their players that is not listed on the home page. After the coach receives this information, they can ask another question or request suggested drills.
Converts kinetic energy from ball rotation/impact into electrical current
bottom of page