A wireless magnetoresistive sensing system for an intraoral tongue-computer interface

Area of Science:

• Biomedical Engineering
• Assistive Technology
• Wearable Sensors

Background:

• The Tongue Drive System (TDS) is a wireless assistive technology (AT) that uses tongue movements for user command input.
• Existing TDS versions may have limitations in terms of invasiveness or unobtrusiveness.

Purpose of the Study:

• To introduce and describe the novel intraoral Tongue Drive System (iTDS).
• To detail the system-on-a-chip (SoC) design, including sensors, transmitter, and power management.
• To demonstrate the feasibility of integrating TDS into a dental retainer form factor.

Main Methods:

• Implementation of the iTDS within a dental retainer using a custom SoC.
• Integration of four 3-axial magnetoresistive sensors to detect intraoral magnetic field variations.
• Inclusion of a dual-band transmitter (27/432 MHz ISM band) and a power management integrated circuit (PMIC) for battery charging and data recovery.
• Utilizing a custom TDS universal interface with commercial off-the-shelf (COTS) components for device connectivity.

Main Results:

• The iTDS SoC, fabricated in a 0.5-μm CMOS process, integrates sensors, a configurable analog front-end (AFE), a dual-band transmitter (Tx), and a PMIC.
• The system supports wireless data streaming to external devices like smartphones, PCs, and powered wheelchairs (PWC).
• The average power consumption of the iTDS SoC is 3.7 mW, with an integrated 50 mAh Li-ion battery rechargeable via an inductive link.

Conclusions:

• The intraoral Tongue Drive System (iTDS) represents a significant advancement in unobtrusive, minimally invasive assistive technology.
• The dental retainer-based iTDS offers a novel and potentially more accessible method for tongue-controlled human-computer interaction.
• The developed SoC demonstrates efficient power management and wireless data transmission capabilities for advanced AT applications.