Design and Implementation of a BLE 5.0-Enabled Wearable Finger Mouse Using the XIAO nRF52840 Platform

Abstract

This paper presents the design, implementation, and evaluation of a compact, ring-worn human–computer interface (HCI) device— termed the FingerMouse—that enables wireless cursor control via thumb-operated joystick input. The system uses the Seed Studio XIAO nRF52840, an ultra-compact microcontroller with native Bluetooth Low Energy (BLE) 5.0 support, to implement a standards-compliant Human Interface Device (HID) profile. This approach eliminates the need for proprietary drivers and provides plug-and-play compatibility across Windows, macOS, and Android platforms. The device operates in two modes: (1) directional cursor movement with left-click actuation, and (2) scroll-wheel emulation with deep-sleep power management. Housed in a custom 3D-printed ring (25 mm inner diameter, <15 g mass) and powered by a 90 mAh LiPo battery, the prototype achieves an average active current draw of 7.2 mA, deep-sleep consumption of <1 μA, and a usable battery life of 4.1 hours. Experimental validation with ten participants confirmed reliable operation, low latency (28 ± 5 ms), and high ergonomic comfort during extended use. This work demonstrates a low-cost, open-hardware solution that advances wearable HCI through miniaturisation, energy efficiency, and seamless OS integration.