Pin City Book: A PCB-based Tangible User Interface for Location-based Puzzle Games
Yibing Chen, Yutong Liu, Zihan Zhou, Yifan Wang, Sihan Wang, Yunyang Di, Quan Li · 2026 · Extended Abstracts of the 2026 CHI Conference on Human Factors in Computing Systems (CHI EA ’26) · doi:10.1145/3772363.3798449
Summary
This CHI 2026 Extended Abstract introduces Pin City Book, a PCB-based tangible user interface (TUI) platform for location-based puzzle games (LBPGs). The authors argue that current LBPGs are split between paper kits (cumbersome, no feedback) and mobile apps (screen-bound, disjointed from the city), and use a three-week design workshop with 12 interdisciplinary participants — including a guided tour of Shanghai’s Bund — to iterate from a laser-cut wooden box, through a plain PCB, to a foldable PCB-in-booklet form factor. The final system reframes the printed circuit board itself as the visible interface, not a hidden substrate: a silkscreened city map carries WS2812 addressable LEDs at building locations, with road networks rendered in silkscreen and water in solder mask. Six modular plug-in boards (control via ESP32-C3, power, motion via MPU6050, haptic, NFC communication, expansion) clip onto the back via board-to-board connectors, so developers can mix and match capabilities without redesigning the whole circuit. Auxiliary components include laser-engraved acrylic building models for sandbox-style placement, paper clue inserts, and a six-hole-punched booklet that holds the whole kit together. The authors validate the platform with Skyline Traveler, a time-travel puzzle in which players decode 5 transparent skyline overlays to locate 16 Shanghai landmarks across five eras (1995–2020), and report a between-subjects player study (N=28) and a developer competition (N=15).
Key findings
In the player study, the PCB-based condition (n=14) outperformed a paper-plus-phone control (n=14) on every measured dimension. Interest and enjoyment: enjoyment 5.93 vs 5.07 (p=.0482), interaction fun 6.21 vs 4.07 (p=.0001), immersion 5.57 vs 3.86 (p=.0018). Environmental understanding: architectural familiarity 5.64 vs 4.64 (p=.0418) and factual recall 10.21/16 vs 8.57/16 (p=.0342). Social engagement: willingness to interact 5.86 vs 4.14 (p=.0008) and observed peer exchanges 2.14 vs 1.14 (p=.0363). The developer competition with 15 non-technical participants produced working extensions — shake-to-light, gravity sandbox, custom gold-finger PCBs, GPS module — supporting claims of feasibility, accessibility (low barrier to authoring), and extensibility. The authors articulate three interaction modalities (device-centric, environment-contextual via GPS/NFC, social) and four gameplay formats (Information Hunt, Mission Challenge, Role-Playing, Multiplayer Engagement). Limitations are explicit: small samples, short-term sessions, and a single evaluation site (Shanghai students new to the city). Future work points to longitudinal studies and an LLM-supported authoring pipeline to lower the barrier further.
Relevance
Although Pin City Book is framed as a maker / urban-play project rather than an accessibility one, the system sits squarely in the TUI tradition that accessibility researchers have drawn on for decades — tangible interaction has been used in autism research (cited here in Francis et al. 2019), in cognitive and dementia care, in early-literacy work, and in non-visual interfaces. Several design choices transfer directly to inclusive design: physical building models give a non-visual or low-vision player a graspable reference for spatial relationships; LED + haptic feedback provides redundant multimodal cues; the modular plug-in architecture means an alternative input board (switch, larger pin, audio) could be added without redesigning the system; and the lower technical barrier for non-engineer developers also lowers the barrier for disabled makers and accessibility specialists who want to build their own location experiences. The accessibility limitations are real and unaddressed by the paper itself: the reliance on small acrylic pins and fine motor placement, the use of colour-coded LEDs without secondary encoding, no captions or audio for paper clues, and an outdoor walking premise that excludes wheelchair users on uneven ground. Anyone borrowing this design pattern should treat those as required additions rather than nice-to-haves.
Tags: tangible user interface · multimodal interaction · location-based games · maker accessibility · haptic feedback · cultural heritage · urban play