arXiv subjects

Akihito Noda

Publications and source records attributed to Akihito Noda.

7 recordsLinked to original sources

arXiv2026

Protocol-Flexible Custom NFC for Wire-Free Wearable Sensor Networks

This study presents a custom near-field communication (NFC) system with software-defined protocol implementation for wearable sensors distributed across the body. Conventional wired implementations can degrade wearability because of mechanical constraints, whereas radio-based wireless approaches such as Bluetooth are affected by body-induced signal attenuation and limited communication coverage. The proposed system is compatible with previously demonstrated fabric-integrated meander coils, which provides a feasible path toward garment-scale NFC communication areas. The system combines a microcontroller unit with compact modulation and demodulation circuits, allowing medium access control and other communication protocols to be implemented in software. Experimental results demonstrate continuous acquisition of three-axis acceleration data from three sensor tags, achieving a per-tag polling rate of $222\,\mathrm{Hz}$ and an effective throughput of approximately $16\,\mathrm{kbps}$, delivering $156$ valid samples per second per tag at a measured packet error rate of $30\%$.

cs.NI↗

arXiv2026

UART for Wearables (U4We): DC Power and Carrierless Signal Transfer over Conductive Textiles

This brief presents a circuit-level conductive-textile interconnection technique for batteryless distributed wearable modules. Two conductive textile layers separated by an insulating fabric layer are used as a garment-wide shared bus that simultaneously conveys DC power and pulse-based data signals without point-to-point wiring. To minimize the circuit overhead of each module, universal asynchronous receiver/transmitter (UART) pulses are directly coupled onto the textile through AC-coupling capacitors without carrier modulation. The textile is modeled as a lumped resistance--capacitance network. The textile waveform is then modeled as the transient response of a second-order circuit. From this model, design conditions for comparator-based waveform recovery and high-bitrate transmission are analytically derived. The resulting design framework determines whether a given combination of data rate, textile capacitance, and resistance is feasible, and also provides the corresponding design range of the decoupling inductors. The required textile parameters are characterized, and robustness to parameter drift is analyzed. These results establish a basic methodology for textile-based simultaneous power and data transfer.

eess.SP↗

arXiv2025

Ultra-low-power ring-based wireless tinymouse

Wireless mouse rings offer subtle, reliable pointing interactions for wearable computing platforms. However, the small battery below 27 mAh in the miniature rings restricts the ring's continuous lifespan to just 1-10 hours, because current low-powered wireless communication such as BLE is power-consuming for ring's continuous use. The ring's short lifespan frequently disrupts users' mouse use with the need for frequent charging. This paper presents picoRing mouse, enabling a continuous ring-based mouse interaction with ultra-low-powered ring-to-wristband wireless communication. picoRing mouse employs a coil-based impedance sensing named semi-passive inductive telemetry, allowing a wristband coil to capture a unique frequency response of a nearby ring coil via a sensitive inductive coupling between the coils. The ring coil converts the corresponding user's mouse input into the unique frequency response via an up to 449 uW mouse-driven modulation system. Therefore, the continuous use of picoRing mouse can last approximately 600 (8hrs use/day)-1000 (4hrs use/day) hours on a single charge of a 27 mAh battery while supporting subtle thumb-to-index scrolling and pressing interactions in real-world wearable computing situations.

cs.HC↗

arXiv2025

Full-body NFC: body-scale near-field sensor networks with machine-knittable meandered e-textiles

Wireless body networks comprising battery-free on-body sensors and textile-based wireless readers can enable daily health monitoring and activity tracking by continuously monitoring physiological signals across the body. However, previous textile-based wireless networks made of coils or antennas have limited the data and power transmission area because covering the whole body results in undesirable levels of electromagnetic interactions with the body, degrading the scalability, power consumption, and data rate. Here, we report Full-body NFC, digitally-knitted electronic textiles based on a twin meander coil design that enables body-scale near-field communication (NFC) with battery-free sensor tags arbitrarily placed around the body. Full-body NFC features i) a meander coil that enhances the magnetic field intensity on the body's surface while suppressing undesired interactions with deep tissues, in addition to ii) paired identical coil structure that enables highly-sensitive and motion-robust NFC using a differential architecture. Additionally, industrial digital knitting machines loaded with conductive yarn allow the integration of the Full-body NFC system into daily garments supporting approximately $70-80\%$ large-scale NFC-enabled area of the body. We demonstrate Full-body NFC could achieve mW-class energy-efficient near-field sensor networks with hundreds of kbps-class NFC battery-free sensor tags occupying less than $0.3\%$ of the coverage area under severe body movements.

cs.HC↗

arXiv2019

Inter-IC for Wearables (I2We): Power and Data Transfer over Double-sided Conductive Textile

We propose a power and data transfer network on a conductive fabric material based on an existing serial communication protocol, Inter-Integrated Circuit (I2C). We call the proposed network Inter-IC for Wearables (I2We). Continuous dc power and I2C-formatted data are simultaneously transferred to tiny sensor nodes distributed on a double-sided conductive textile. The textile has two conductive sides isolated from each other and is used as a single planar transmission line. I2C data are transferred along with dc power supply based on frequency division multiplexing (FDM). Two carriers are modulated with the clock (SCL) and the data (SDA) signals of I2C. A modulation and demodulation circuit is designed to enable using off-the-shelf I2C-interfaced sensor ICs. One significant originality of this work is that a special filter to enable passive modulation is designed by locating its impedance poles and zeros at appropriate frequencies. The proposed scheme enables flexible implementation of wearable sensor systems in which multiple off-the-shelf tiny sensors are distributed all over a wear.

eess.SP↗

arXiv2017

Acoustic Macroscopic Rigid Body Levitation by Responsive Boundary Hologram

Propagated acoustic waves, which generate radiation pressure, exert a non-contact force on a remote object. By suitably designing the wave field, remote tweezers are produced that stably levitate particles in the air without any mechanical contact forces. Recent works have revealed that holographic traps can levitate particles even with a single-sided wave source. However, the levitatable objects in the previous studies were limited to particles smaller than the wavelength, or flat parts placed near a rigid wall. Here, we achieve a stable levitation of a macroscopic rigid body by a holographic design of acoustic field without any dynamic control. The levitator models the acoustic radiation force and torque applied to a rigid body by discretising the body's surface, as well as the acoustic wave sources, and optimizes the acoustic field on the body surface to achieve the Lyapunov stability so that the field can properly respond to the fluctuation of the body position and rotation. In an experiment, a 40 kHz (8.5 mm wavelength) ultrasonic phased array levitated a polystyrene sphere and a regular octahedron with a size of ~50 mm located 200 mm away from acoustic elements in the air. This method not only expands the variety of levitatable objects but also contributes to microscopic contexts, such as in-vivo micromachines, since shorter-wavelength ultrasound than the size of target objects can be used to achieve higher controllability and stability.

physics.app-ph↗

arXiv2017

Electronically Steerable Ultrasound-Driven Air Stream

We have created a stretching air flow by generating a Bessel beam of ultrasound with an active phased array of acoustic transducers in free space. The generated Bessel beam is electronically steerable in terms of its position and direction of propagation. The fastest spot in the flow could be located apart from the sound source itself. The flow is formed immediately after the sound field is generated, which can be electronically accomplished with the phased array that we fabricated. We formulate the basic technique for realizing such air-borne flows and experimentally describe their physical properties. Our technique would be capable of controlling the air flow in free-space with an improved temporal and spatial resolution compared with those conventionally considered.

physics.flu-dyn↗