Lotio: Lotion-Mediated Interaction with an Electronic Skin-Worn Display

Document Title

Lotio: Lotion-Mediated Interaction with an Electronic Skin-Worn Display

Document Information

• Subject Area: Human-Computer Interaction, Wearable Devices, Electronic Skin Interface Design
• Keywords: Wearable Devices, Ambient Display, Lotion, Skin Interface, Electronic Skin, Dynamic Display, Eco-Friendly Materials

Research Background and Problem

• Problem or Challenge:
  • With the rapid development of electronic skin technologies, designing low-power, eco-friendly interfaces that integrate seamlessly with everyday behaviors (e.g., applying lotion) remains a challenge.
  • Current skin interfaces often rely on complex circuits or expensive materials, lacking practicality, environmental friendliness, and seamless integration with human habits.
• Research Significance:
  • Human skin is a universal, cross-cultural interaction medium. Combining it with everyday behaviors like lotion application can transform human-computer interaction experiences and introduce new dimensions to interface design.
• Research Motivation and Related Work:
  • While various biomedical sensing technologies and dynamic skin display systems have made progress, leveraging natural behaviors like lotion application to drive interface functionality has not yet been explored.
  • This study combines the behavior of lotion application with the design of a degradable, low-power skin display device, exploring new use cases for skin technology.

Solution

• Proposed Method or Solution:
  • Lotion Interfaces: Utilizing lotion as an interaction medium, controlling the color, texture changes, or data display of electronic skin through electrochemical reactions.
  • Designed the Lotio interface device: a dynamic skin overlay based on electrochromic technology that can sense and respond to external stimuli in real time through lotion application.
• Innovations:
  • Introducing lotion as a medium to trigger the interface, proposing a novel interaction model of "lotion interfaces."
  • Using simple, eco-friendly materials (e.g., PEDOT:PSS conductive polymer) and low-power circuit designs to reduce manufacturing complexity, costs, and improve environmental sustainability.
  • Achieving dynamic changes in skin displays, such as color reactions or health feedback, after lotion application.
• Implementation Steps:
  • Constructed an electrochromic layer based on PEDOT:PSS, combined with transparent or breathable substrate materials (e.g., cellulose acetate or surgical tape).
  • Created high-resolution personalized designs using simple air-spraying techniques and laser cutting.
  • Used resistance sensing and conductive path recognition to distinguish between different interaction methods, such as pressing or lotion application.
  • Connected to a microcontroller (e.g., Arduino or ATtiny85) to enable real-time interaction between the user and Lotio.
• Key Technologies:
  • Electrochromic technology: Generating color changes by altering the oxidation-reduction state of materials through electrical input.
  • Resistance-based tactile sensing technology to differentiate interaction modes like pressing or lotion application.
  • Biodegradable materials and DIY-friendly manufacturing processes.

Research Outcomes

• Specific Outcomes:
  • Lotio can sense lotion and trigger dynamic displays, such as color changes from bright to dark or activating connected device functions via electrical signals.
  • The prototype device has extremely low power consumption (0-350μW), can be powered by simple batteries, and exhibits quasi-bistable characteristics, maintaining display effects for tens of minutes.
  • Lotio was validated to distinguish different touch modes (pressing without lotion vs. applying lotion) through resistance sensing.
• Advantages Over Existing Solutions:
  • Compared to other skin technologies based on LEDs or thermochromic materials, Lotio consumes less power and does not require complex circuits or expensive materials.
  • The PEDOT:PSS substrate is eco-friendly and easily degradable, making it more suitable for short-term use.
  • The system can integrate lotion types to semantically present health data, seamlessly aligning with users' daily behaviors.
• Experimental or Evaluation Results:
  • The thickness of PEDOT:PSS significantly affects display contrast, with the optimal thickness being 1.23μm.
  • Different lotion types (e.g., sunscreen, ointments) provide varying visual effects and switching speeds (display change times ranging from 2 to 15 seconds).
  • User studies revealed that the Lotio concept was well-received by most participants, particularly for health data visualization and dynamic cosmetic applications.
• Limitations and Future Directions:
  • Limitations:
    • The display layer (PEDOT:PSS) is susceptible to damage from alcohol-based products, and device durability needs improvement.
    • In large-scale applications, the resistance of PEDOT:PSS may increase, affecting performance.
    • Users expressed some resistance to the unnatural experience of lotion not being fully absorbed (e.g., due to the current cellulose substrate).
  • Future Directions:
    • Develop more durable and reusable Lotion Interface designs.
    • Explore additional interaction dimensions triggered by lotion (e.g., tactile feedback, thermal sensations, scents).
    • Advance more complex multi-pixel display technologies to support dynamic information transmission and multifunctional input/output.

By incorporating everyday lotion application behaviors, this research expands the potential applications of skin technology and wearable devices, opening new perspectives for skin interaction technologies.