InkStack: A Programmable E-Paper Card System for Board Games

Paper Title

InkStack: A Programmable E-Paper Card System for Board Games

Publication Info

• Topic area: Interactive e-paper cards for hybrid board games
• Keywords: e-paper, interactive cards, hybrid board games, HCI, game mechanics, immersion, tangible interaction, augmented board games, digital displays, role-playing games

Background and Problem

• Problem / challenge: Traditional paper cards in board games are limited by fixed content, fragility, and bulkiness, while smartphones, though functional, disrupt immersion and social interaction.
• Significance: Addressing these limitations can enhance gameplay by combining the tactile qualities of physical cards with the adaptability of digital media, enabling novel interactions and reducing material waste.
• Motivation and related work: Prior research in HCI has focused on augmenting board games with AR, tabletops, and AI, but playing cards remain underexplored. Existing smart card systems often lack usability or compromise tactile qualities, leaving a gap for solutions that balance digital flexibility with physical interaction.

Solution

• Proposed approach: InkStack, a system of interactive e-paper playing cards, a programmer unit, and a web-based GUI for dynamic content updates.
• Novelty:
  1. Combines the tangible qualities of physical cards with the adaptability of digital displays.
  2. Introduces a reusable, programmable e-paper card system without embedded power supplies.
  3. Supports diverse game mechanics, including randomization, character updates, and map exploration.
  4. Provides a user-friendly web-based interface for card customization and management.
• Procedure and key techniques:
  1. Developed thin e-paper cards with 3D-printed casings and pogo-pin-based reprogramming.
  2. Designed a programmer unit with an ESP32 microcontroller for updating card content via Wi-Fi.
  3. Created a web-based GUI for editing, uploading, and managing card graphics.
  4. Evaluated the system in a within-subject study with n = 20 participants across four game mechanics.

Results

• Concrete findings:
  • InkStack scored highest in usability for "shuffling and drawing cards" (M = 88.33, SD = 9.52) and "statistics and equipment updates" (M = 74.17, SD = 21.27), outperforming smartphones and paper in these mechanics.
  • No significant usability differences were found for "exploring the map" and "quiz" mechanics.
  • Participants ranked InkStack as the most preferred medium for three out of four mechanics.
• Advantage over baselines:
  • Outperformed smartphones and paper in usability for complex mechanics requiring frequent updates or randomization.
  • Preserved tactile qualities while offering digital flexibility, avoiding the distractions associated with smartphones.
• Experiments / evaluation:
  • Tested four mechanics: shuffling/drawing cards, statistics updates, map exploration, and quizzes.
  • Compared InkStack with paper and smartphone alternatives using UMUX-LITE scores, preference rankings, and interviews.
  • n = 20 participants with diverse board game experience; counterbalanced study design.
• Limitations and future work:
  • High cost of e-paper displays and slow programming process.
  • Limited ecological validity due to one-on-one study format and isolated mechanics testing.
  • Plans for faster updating methods, thinner cards, flexible screens, and extended multiplayer evaluations.

Summary

InkStack is a hybrid board game system combining the tactile qualities of physical cards with the adaptability of e-paper displays. Evaluated with n = 20 participants across four game mechanics, it showed significant usability advantages in tasks requiring frequent updates or randomization, outperforming smartphones and paper. While limitations such as cost and programming speed remain, InkStack demonstrates the potential of e-paper as a versatile design material for augmented board games, preserving traditional gameplay affordances while enabling novel interactions. The system offers a pathway toward hybrid games that balance digital and physical qualities, enhancing both immersion and versatility.