A New Approach for Readout of Resistive Sensor Arrays for Wearable Electronic Applications

Abstract

Resistive sensor arrays have been increasingly adopted in wearable electronic applications, which require low-complexity and low-energy circuits. However, current readout strategies for resistive sensor arrays require additional electrical components such as transistors, diodes, multiplexers, op-amps, switches, current sources and A/D converters, leading to a considerable increase in circuit complexity, power consumption, system instability and crosstalk error. To address the problem, this paper proposes a new approach, which determines sensor resistance values by establishing and solving resistance matrix equations of sensor arrays. Unlike conventional approaches, it allows crosstalk currents in arrays to avoid additional components that are originally used for eliminating crosstalk currents and minimizing crosstalk error. Meanwhile, it takes advantage of on-chip resources of wearable platforms, thereby reducing redundant chips. It was implemented on a prototype of 10×10 textile resistive sensor array, which was taken in a sensing cushion for sitting pressure monitoring of chair bound people. Experimental results on this array platform showed the new approach achieved a satisfactory accuracy (0.61±0.41%), as well as a low crosstalk error (2.77±0.61‰). The fabricated sensing cushion also exhibited a relatively low pressure measurement error (6.30±0.75%). Compared with other approaches, the proposed approach demonstrated the lowest circuit complexity on a microcontroller based wearable platform, and a sufficient sensor capacity. It is ideal for a wide range of applications like wearable or implantable sensing, presenting a reference for the design of low-complexity and low-crosstalk error wearable systems based on resistive sensor arrays.

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

“…The maximum time of t set arises for a combination of R s and R ref equals to 1 M (i.e., 5 × (1 M || 1 M ) × 1 nF = 2.5 ms), where the C c is set to optimal value of 1 nF sufficient to avoid the supply fluctuations meanwhile reducing the delay time. The settling time in unity-gain feedback of the OPAMP used in the design is 1.6 µs [42] which is negligible compared to the settling time of 2.5 ms calculated using (12) and thus can be neglected.…”

“…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…”

Review of Measuring Microenvironmental Changes at the Body–Seat Interface and the Relationship between Object Measurement and Subjective Evaluation

“…Publications were classified in accordance with the number of sensors being used in the pressure measurement (Figure 4). To reduce the complexity and high power consumption of electronic circuits (the inherent property of resistors), Shu et al [59] proposed a resistance matrix approach (RMA) which identified sensor outputs by solving the resistance matrix equations. Compared with traditional approaches, RMA improved the efficiency and attenuated the complexity by eliminating the redundant components (e.g., external current sources used to prohibit crosstalk noise).…”

SmartSleeve

“…First we analyzed how our system behaves with a solution without crosstalk reduction [53]. Further, we evaluated the effects of grounding for crosstalk reduction [10], the zero potential method [56] and virtual grounding [52], the multiplexer op-amp assist approach [51], and the resistive matrix approach [57].…”

“…Measurement Principle Average Error Without reduction [53] 34.5% Grounding [10] 32.1% Virtual Grounding [52] 42.6% Multiplexer & Op-Amp assisted approach [51] 10.5% Resistive Matrix Approach [57] 0.93% Table 2: Overview of the measurement principles.…”