WHAT IS RE:VOLTS?RE:VOLTS is a smart footwear and app that generates and tracks renewable energy through every step to power everyday devices
RE:VOLTS is a smart shoe that converts every step into renewable energy. It generates electricity as you walk and stores it in a removable portable charger, allowing users to power devices wherever they go. The smart shoe and data is connected through an app that tracks steps, distance, energy generation and battery levels. This makes everyday movement become a sustainable source of power.
Role
End-to-End Product Designer
Timeframe
3 weeks
Tools
Figma and Blender
TL;DROverview
Designed a smart shoe and app that converts everyday steps into renewable energy, powering devices on the go.
Research
Attended the Sneakers Unboxed exhibition and a Chatham House panel on footwear electronics, then ran a competitive audit - finding a genuine market gap for self-generating energy footwear.
App design
Designed a circular charge indicator to visualise energy generation, paired with a futuristic design system, day/week/month/year data views, and line graphs to track activity trends over time.
Physical shoe design
A prototyped push-mechanism concept proved too noisy and bulky for real footwear. I tested a piezoelectric alternative instead - 100 steps generated enough energy to power a light for 17 seconds, validating a more practical direction.
Outcome
Turned everyday movement into usable energy, reduced reliance on portable chargers, and made an otherwise invisible source of power visible and motivating through the app.
Keeping devices powered on the go remains a challenge and everyday movement goes unused
THE PROBLEMSDevices running out of battery
Portable chargers are too bulky, easy to forget and still rely on access to main electricity sources
Everyday movement is largely wasted
A smart shoe that transforms everyday kinetic energy and pressure into electricity, stored within a removable power bank that charges devices on the go, while activity/energy insights are tracked through the app
By harnessing the kinetic energy and pressure generated with every step, the shoe produces electricity that is stored within an integrated, removable power bank. This eliminates the need to carry bulky portable chargers or rely on access to mains electricity, ensuring power is always available when users are on the move. The RE:VOLTS app tracks steps, distance, energy generation, and battery levels, giving users real-time insights into their activity and embeds energy generation directly into products people use every day.
THE SOLUTIONIMPACT 1Turns wasted movement into useful energy
through everyday movement becomes an to generate and store electricity.
IMPACT 2Makes charging more seamless
by integrating energy generation into something users already need to wear, removing the need to remember a separate power bank.
IMPACT 3Reduces battery anxiety
by providing users with an additional source of power when their devices are running low and to generate power on the go.
Charging interrupts users daily routines
User personas were created to understand how different people use and charge their devices throughout the day, identifying where low battery and existing charging solutions interrupt their routines. These insights identified opportunities to seamlessly integrate energy generation into everyday life through RE:VOLTS.
THE USERS
“I’m active everyday and I want technology that works seamlessly while I move.”
Jason Williams
Age: 25
Education: Physio Therapy
Hometown: London, UK
Occupation: Personal Trainer
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Jason loves wearable technology that is not bulky and enjoys testing new fitness innovations. He tracks his health and moves a lot everyday due to his job and fitness goals.
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Improve fitness performance
Monitor movement accurately
Use innovative sports technology
Reduce reliance on charging devices
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Wearables with poor battery life
Inaccurate fitness tracking
Products that prioritise style over functionality
Apps with confusing dashboards
“It’s frustrating when I’m out travelling for work and I run out of battery by midday.”
Tae Lim
Age: 42
Education: Economics Graduate
Hometown: Seoul, South Korea
Occupation: Consultant
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Tae travels frequently for work and often spends long hours commuting and walking through airports and cities. Keeping devices charged while travelling is a constant concern, especially during busy travel schedules. He forgets his portable charger from time to time and is normally left with no battery by the end of lunch.
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Keep devices charged on the move
Reduce dependence on charging stations
Simplify travel tech
Stay active despite frequent travel
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Searching for charging points
Carrying multiple cables and power banks
Low phone battery during travel
Bulky wearable devices
Battery anxiety during long days out
MARKET RESEARCH - SNEAKERS UNBOXED EXHIBITION AT THE DESIGN MUSEUMSneakers Unboxed exhibition demonstrated how technology can be integrated into footwear and inspired RE:VOLTS’ minimalist, sleek, and future-focused design direction
As part of the initial research, I visited the Sneakers Unboxed exhibition at the Design Museum to explore future footwear innovations and the integration of technology into shoes. The exhibition showcased smart footwear concepts from brands including Nike, Adidas, Puma, and MIT Design Lab, inspiring RE:VOLTS minimal, sleek, and bold visual direction. The self-fitting Adapt BB shoes were displayed and demonstrated how technology can be seamlessly integrated into footwear through app-controlled features such as battery monitoring, custom fit profiles and LED settings.
MARKET RESEARCH - REINVENTING SNEAKERS PANEL AT CHATHAM HOUSEReinventing Sneakers Chatham House panel explored the constraints of integrating electronics into footwear
I attended the panel discussion Reinventing Sneakers: Will Shoes Have a Regenerative Future? at Chatham House, which explored the challenges and opportunities of integrating electronics into footwear. Key considerations included reducing the size and bulk of embedded technology, ensuring durability through shock absorption and weather resistance, improving sustainability, and designing systems that allow for maintenance and replacement of electronic components.
A competitive analysis was conducted to identify technological opportunities within the project's manufacturing and budget constraints. It also provided inspiration for how brands create a cohesive experience across the shoe, app, and visual identity, as well as effective ways to present user data through infographics.
COMPETITIVE AUDIT + ANALYSISPRIMARY TAKEAWAY
Gap in the market for footwear that generates its own renewable energy. Also, dark colour palettes, bold accents, and clean interfaces successfully create a futuristic aesthetic.
Ideation explored how RE:VOLTS could benefit different users and scenarios while identifying new ways to increase user engagement
Collaborative ideation was used to explore a wide range of possibilities without limiting creativity and delved into the concept for alternate target audiences and scenarios. Ideas such as battery notifications through shoe vibrations, yearly activity recaps, and energy sharing highlighted opportunities to create a connected, personalised experience and uncovered speculative concepts.
COLLABORATIVE IDEATION
Mapping and understanding the connection between physical and digital experience
A storyboard was created to visualise how users interact with both the shoe and app throughout their journey. Mapping the experience helped define the connection between the physical and digital touchpoints, looking into monitoring their activity and energy generation and using the integrated power bank to charge separate devices.
STORYBOARD
Presenting data and visualising charge as a circular progress indicator
This stage focused on presenting movement and charging data within the app. I developed a range of wireframes before selecting a circular charging indicator to test further, inspired by insights from the competitive audit. My hypothesis was that completing the circle would create a satisfying sense of progress, motivating users to generate more energy through everyday movement. I then refined layouts to prioritise key information, including charge level, step count, and distance travelled.
IDEATION + WIREFRAMING
Making shoe-to-app connection and energy generation understandable and motivating by displaying charge progress, supporting multiple shoe connections, and minimising screens
Showing how everyday movement is being translated to energy by displaying progress towards a full charge aimed to help users understand the product’s purpose and has the intention of giving the user a clear goal. Supporting multiple shoe connections aims for a seamless experience across pairs and a minimal number of screens prioritised key information to be easily accessible. These decisions focused on making the RE:VOLTS experience clear, motivating, and simple.
LOW-FIDELITY PROTOTYPE
Usability testing identified confusion and validated the charging experience through visual progress, colour feedback, and prioritising features
The first usability test was conducted to identify confusion and validate key design decisions. Users found that a percentage alone did not clearly communicate charge level, highlighting the need for stronger visual cues. The circular charging indicator validated the hypothesis that visual progress feels motivating, while colour changes could further indicate charge level. Daily goals and achievements were not prioritised at this stage, as the focus remained on the core charging experience, but could be considered in future iterations.
FIRST USABILITY TEST
Developed a futuristic design system informed by competitive insights, usability testing, and visualising energy generation
The design system was developed to create a futuristic aesthetic, informed by insights from the competitive audit as a result a dark colour palette with a bold, bright, contrasting green accent was chosen. Following usability testing, orange was introduced as an additional colour cue to reinforce charge level. Stretch Sans and Fontspring complements the futuristic visual style due to its bold style. I rendered a 3D bubble-like visual which adds depth and helps visualise energy generation.
DESIGN SYSTEM
Collaborating with a fashion designer to create a futuristic shoe design that connects with the app’s visual language and integrates electronic components
The shoe visual designs were developed in collaboration with a fashion designer/illustrator, combining a futuristic aesthetic with visual cues inspired by the app’s charge bubble. The designs also considered the practical need to integrate and accommodate all electronic components within the shoe.
VISUAL SHOE DESIGNS
Homepage
Multiple connected shoes allow users to view the currently worn shoe and charge level of each pair.
A quick overview of shoe status and available charge makes key information accessible at a glance.
HIGH-FIDELITY PROTOTYPE
Data screens
“Charge” added after the percentage following usability testing makes the value immediately understandable.
The charge circle and bubble visualise energy levels and reinforce progress towards a full charge while supporting the futuristic UI.
Orange indicates remaining charge, responding to usability testing feedback and providing a clearer visual cue.
Day, week, month, and year views allow users to explore their activity and energy data across different time periods.
Daily activity and progress information shows completed steps and distance alongside what remains to reach a full charge.
Graphs
Line graphs shows trends over time with minimal visual clutter and complements the circular charging UI.
Average steps and distance provide an overview of overall activity.
Individual date selection allows users to explore their steps and distance in more detail.
Second usability testing identified opportunities for wearable integration, dynamic energy feedback, and improved accessibility
The second usability test found that users could easily understand the data and navigate the app, with the visual design perceived as high-tech and futuristic. Users highlighted they often use smartwatches to track activity as they are less bulky and do not interrupt movement, suggesting an opportunity for a wearable version. As energy was associated with movement and flow, the static interface highlighted an opportunity for animation to communicate charge levels more dynamically. The colour scheme reinforced the futuristic aesthetic, but an alternative palette could improve accessibility.
SECOND USABILITY TEST
MAIN REFINEMENTS BASED ON THE SECOND USABILITY TESTSmartwatch
Problem
The phone can feel bulky and requires users to stop and access it, interrupting movement and making it less convenient to check charge and activity data.
Solution
A smartwatch version provides quick access to charge and activity data while on the move, keeping users engaged with their movement without needing their phone.
Accessibility colour theme
Problem
The original colour scheme lacked sufficient contrast for users with visual impairments.
Solution
A refined blue and orange palette improves contrast and accessibility while maintaining the app’s bold visual identity.
Charge bubble animation
Problem
The static charge bubble did not fully communicate changes in charge level or reinforce the futuristic nature of the experience.
Solution
A dynamic bubble animation provides clearer visual feedback as charge levels change while enhancing the app’s futuristic UI.
SHOE ENERGY GENERATION AND POWER BANK DESIGN IDEATIONMaking RE:VOLTS tangible by exploring different energy-generation methods and prototyping power bank placement
This stage focused on making RE:VOLTS tangible by ideating different ways to generate electricity within the shoe, including push mechanisms, piezoelectric pressure, heat, water, and wind. Informed by the competitive audit, I also tested different power bank placements and removal methods using paper mock-ups.
Developing 2 energy-generation concepts (pressure sensors and push mechanism cog) to convert movement into electricity while integrating energy storage and Bluetooth connectivity
Collaborating with developers at HackSpace, 2 viable energy-generation concepts were developed: piezoelectric pressure sensors within the insole, converting pressure from each step into electricity, and a push mechanism using a cog system and motor to convert movement into energy. Both concepts included a battery for energy storage and Bluetooth connectivity to send movement and charge data to the app, connecting the physical and digital experience.
TECHNICAL EXPLORATION
Piezoelectric pressure sensors in insoles
Push mechanism with cog and motor
Validating energy-generation concepts through testing, leading to the selection of piezoelectric technology as the more practical solution
To test the piezoelectric concept, sensors were connected to a small light to measure energy generated through movement. After 100 steps, enough energy was produced to power the light for 17 seconds, demonstrating the potential of pressure-based energy generation. A push mechanism was also tested but proved too noisy, bulky, and potentially uncomfortable for everyday footwear. As a result, I progressed with the piezoelectric direction as the more practical solution.
TESTING
It works!
The prototype used multiple piezoelectric sensors across the insole to maximise energy generation from movement and pressure. A fuel gauge displayed the stored charge, while Bluetooth connected movement and charging data to the companion app. Testing demonstrated that the prototype could generate electricity and connect the physical and digital experience.
LOW-FIDELITY SHOE PROTOTYPE
OUTCOMEHomepage
Data/graphs
RE:VOLTS shoe
Turning everyday movement into useful energy, reducing reliance on portable chargers, and making charge levels visible through the app to reduce the stress of running out of battery
RE:VOLTS transforms everyday movement into a useful source of renewable energy, reducing reliance on bulky portable chargers and traditional power sources. By integrating energy generation into something users already wear, it makes charging more seamless while reducing the stress of running out of battery. The connected app also makes this otherwise invisible energy visible, helping users understand and engage with the impact of their movement.
OUTCOME + IMPACTBridging physical product design and digital UX while developing skills in interactive data visualisation and infographic design
This project strengthened my understanding of how physical product design and digital UX can work together to create a connected experience, while developing my ability to present interactive data and infographics in a clear and engaging way.
KEY TAKEAWAYSImagining the future of RE:VOLTS through rewards, personalisation and exploring how everyday movement could evolve from personal charging into a shared source of energy
Future development could explore reward systems, personalised data views, and community features to encourage movement and energy generation. On the physical side, further development could reduce the shoe’s bulk and improve weather, sweat, and shock resistance, while testing different footwear types.
Looking at RE:VOLTS more speculatively, could generated energy become a form of currency, allowing users to exchange power with one another? Could the combined energy from our everyday steps eventually contribute to powering a city?
NEXT OPPORTUNITIES
