Cross-Device Motion Interaction via Apple's Native System Frameworks

TL;DR

This paper presents an open-source, offline motion interaction system for iPhones that enables real-time tactile feedback and peer-to-peer communication, suitable for research, gaming, and educational applications.

Contribution

It introduces a fully offline, native Apple framework-based pipeline for motion control with low latency, zero packet loss, and minimal power consumption, all implemented in under 500 lines of Swift.

Findings

Mean latency of 70.4 ms with 95th percentile below 74 ms

Stable peer-to-peer connections with zero packet loss during tests

Negligible power impact of 24 mW on iPhone 13 mini

Abstract

We introduce an open-source, fully offline pipeline that transforms a consumer-grade iPhone into a motion controller with real-time tactile feedback, using only native Apple frameworks. Designed for rapid prototyping and applied mobile HCI scenarios, the system integrates CoreMotion for inertial sensing, MultipeerConnectivity for peer-to-peer data transmission at 10 Hz, and CoreHaptics for immediate tactile confirmation. A built-in logger captures end-to-end latency without requiring clock synchronization, yielding a mean delay of 70.4 ms and 95th percentile below 74 ms on typical 5 GHz Wi-Fi (-55 dBm RSSI). We validated the pipeline through a real-time demonstrator game, KeepCalm, deployed during a public event with 21 participants. Results showed stable connections, zero packet loss, and negligible power impact (24 mW on iPhone 13 mini). With fewer than 500 lines of Swift code and no reliance on cloud infrastructure, this system provides a compact, reproducible foundation for embodied interaction research, casual games, and offline educational tools. All source code, latency logs, and provisioning scripts are openly released under an MIT license.