High Density Resistive Array Readout System for Wearable Electronics

Abstract

This work presents a wearable sensing system for high-density resistive array readout. The system comprising readout electronics for a high-density resistive sensor array and a rechargeable battery, was realized in a wristband. The analyzed data with the proposed system can be visualized using a custom graphical user interface (GUI) developed in a personal computer (PC) through a universal serial bus (USB) and using an Android app in smartphones via Bluetooth Low Energy (BLE), respectively. The readout electronics were implemented on a printed circuit board (PCB) and had a compact dimension of 3 cm × 3 cm. It was designed to measure the resistive sensor with a dynamic range of 1 KΩ–1 MΩ and detect a 0.1% change of the base resistance. The system operated at a 5 V supply voltage, and the overall system power consumption was 95 mW. The readout circuit employed a resistance-to-voltage (R-V) conversion topology using a 16-bit analog-to-digital converter (ADC), integrated in the Cypress Programmable System-on-Chip (PSoC®) 5LP microcontroller. The device behaves as a universal-type sensing system that can be interfaced with a wide variety of resistive sensors, including chemiresistors, piezoresistors, and thermoelectric sensors, whose resistance variations fall in the target measurement range of 1 KΩ–1 MΩ. The system performance was tested with a 60-resistor array and showed a satisfactory accuracy, with a worst-case error rate up to 2.5%. The developed sensing system shows promising results for applications in the field of the Internet of things (IoT), point-of-care testing (PoCT), and low-cost wearable devices.

A Readout System for High Speed Interface of Wide Range Chemiresistive Sensor Array

“…Although [27]- [28] offers a wide input range, the proposed system demonstrated a significantly better measurement time and accuracy. Compared to the R-V techniques realized in [12]- [20], the proposed system showed comparable performance in accuracy with a high speed and compact architecture, which is critical to design an embedded readout system for large sensor array. Our previous work, [20] is targeting the wearable VOLUME 10, 2022 application; thus, the critical performance criteria were small form factor and low power consumption.…”

“…Compared to the R-V techniques realized in [12]- [20], the proposed system showed comparable performance in accuracy with a high speed and compact architecture, which is critical to design an embedded readout system for large sensor array. Our previous work, [20] is targeting the wearable VOLUME 10, 2022 application; thus, the critical performance criteria were small form factor and low power consumption. So that, the accuracy and speed were compromised in the previous work which were 2.5 % and 19.6 ms per sensor, respectively.…”

“…Different signal conditioning readout systems have been proposed to interpret response of chemiresistive sensors, which rely on conventional Resistance-to-Voltage (R-V) conversion using an Analog-to-Digital Converter (ADC) [12]- [20], Resistance-to-Time (R-T) conversion using RC oscillator and timer circuits [21]- [26], Direct…”

An Auto Adjustable Transimpedance Readout System for Wearable Healthcare Devices

“…As the demand for wearable devices for healthcare continues to rise, it has generated a booming market, and the companies are now seeing the opportunities of supplying wearable healthcare technologies to their consumers as beneficial. So far, wristwatches, gloves, patches, headbands, eyeglasses, and necklaces have been reported as types of wearable devices [8][9][10][11][12][13][14][15][16]. The wristwatch is the most affordable and widely invented wearable device type since it can provide good wearing comfort and obtain information from the skin.…”

Enhancement of Ammonia Gas Sensing by Tin Dioxide-Polyaniline Nanocomposite

“…Indium oxide (In2O3) and titanium dioxide (TiO2) are examples of metal-oxide that were doped in polyaniline (PANI) nanofiber [19] and silk fiber [20], respectively, to enhance both sensitivity and limit of detection (LOD) for ammonia gas measurement. The solid-state-probe readout is oftenly on a basic of resistance-to-voltage conversion [21]. In this work, tin dioxide (SnO2) and PANI are of interested.…”