Design of Powering Wireless Medical Sensor Based on Spiral-Spider Coils

Ali Al-Naji,Sadik Kamel Gharghan,Saleem Latteef Mohammed,Javaan Chahl,Mustafa F Mahmood

doi:10.3390/designs5040059

Abstract

Biomedical sensors help patients monitor their health conditions and receive assistance anywhere and at any time. However, the limited battery capacity of medical devices limits their functionality. One advantageous method to tackle this limited-capacity issue is to employ the wireless power transfer (WPT) technique. In this paper, a WPT technique using a magnetic resonance coupling (MRC-WPT)-based wireless heart rate (WHR) monitoring system—which continuously records the heart rate of patients—has been designed, and its efficiency is confirmed through real-time implementation. The MRC-WPT involves three main units: the transmitter, receiver, and observing units. In this research, a new design of spiral-spider coil was designed and implemented for transmitter and receiver units, respectively, to supply the measurement unit, which includes a heart rate sensor, microcontroller, and wireless protocol (nRF24L01) with the operating voltage. The experimental results found that an adequate voltage of 5 V was achieved by the power component to operate the measurement unit at a 20 cm air gap between the receiver and transmitter coils. Further, the measurement accuracy of the WHR was 99.65% comparative to the benchmark (BM) instrument. Moreover, the measurements of the WHR were validated based on statistical analyses. The results of this study are superior to those of leading works in terms of measurement accuracy, power transfer, and Transfer efficiency.

Highlights

With developments in the manufacturing of small portable medical devices, it has become necessary to create alternative energy sources to replace conventional energy sources such as fossil fuels and batteries
Alternative energy sources include wireless power transfer (WPT), piezoelectric cells, solar cells, and ultrasonic sensors that can be used in medical applications [1,2]
Two techniques were investigated in the experiment; the results showed that the power Transfer efficiency was 21.74% and 14.76% at 5 cm in case 1 and case 2, respectively

Summary

Introduction

With developments in the manufacturing of small portable medical devices, it has become necessary to create alternative energy sources to replace conventional energy sources such as fossil fuels and batteries. Research on WPT has focused on performance in terms of efficiency and power transfer at different distances between receiver and transmitter coils. Most research on IC-WPT uses it to enhance power transfer and efficiency at different air-gap distances between coils [12,13,14,15]. One study used MRC-WPT to improve the Transfer efficiency for small household appliances and implanted devices [16]. Other authors have used WPT with MRC to enhance power transfer and efficiency at different air-gap distances between coils to supply medical devices. The functionalities of the heart-rate measurement device were achieved based on MRC-WPT; 5. The heart-rate measurement accuracy, and Transfer efficiency, and power transfer of the MRC-WPT are compared to those reported in related works to confirm its achievement.

Related Works

Research Methodology

Experiment Configuration

Results and Discussion