SpaceMan: Wireless SoC for concurrent potentiometry and amperometry

This work describes the implementation of SPACEMan, a wireless electrochemical system with concurrent potentiometric and amperometric sensing that can be utilised for saliva, sweat or point of care diagnostics. This system is designed with the vision of simpler interfaces for biofluid analysis. With a complete system-on-chip including electrochemical sensing, power management and data transmission, conventional interfaces like wirebonds will no longer be required in post-processing steps. The proposed architecture consists of a sensor front-end with four electrodes for concurrent amperometric and potentiometric sensing. This front-end outputs square wave signals mixed together with varying frequencies dependent on the sensed input, with the output type switchable with a state machine. A power management system consisting of a low dropout regulator (LDO) band gap reference (BGR), and a rectifier bridge is utilised for supplying power from an inductive link at 433MHz. Sensor data is transmitted wirelessly to a base station using LSK (Load-Shift Keying). The sensor front-end consumes 18µW, which the power management system more than adequately provides. The core area of the electronics without the coil is a conservative size of 0.41mm 2

A Wireless system for continuous in-mouth pH monitoring

An indication of the dental health of patients can be observed from the pH levels of their saliva. This work presents a first prototype of a smart Orthodontic Bracket (SOB) for continuous monitoring of pH in mouth. The SOB system uses Iridium Oxide (IrOx) pH sensor with 68.8 mV/pH measured sensitivity and is powered through Near Field Communications (NFC) using a smart-phone from a distance of 3.5 cm. The system resolves pH change of 0.15 within a wide range of pH. The system is encapsulated in bio-compatible Epoxy resin and successfully used to measure the pH in Saliva

DAPPER: a low Power, dual amperometric and potentiometric single-channel front end

DAPPER is a front end system capable of simultaneous amperometric and potentiometric sensing proposed for low-power multi-parameter analysis of bio-fluids such as saliva. The system consists of two oscillator circuits, generating a frequency relative to their sensed current and voltage signals. These signals are then mixed together to produce a single channel output that can be transmitted through backscattering (load-shift keying). The entire system consumes 40μW from a 1.4V supply. The linear ranges of potentiometry and amperometry circuits are 0.4V - 1V and 250pA - 5.6μA (87dB), and their input referred noise is 1.7μV and 44.6fA, respectively

Concurrent Potentiometric and Amperometric Sensing with Shared Reference Electrodes

Potentiometry and amperometry are the two most common electrochemical sensing methods. They are conventionally performed at different times, although new applications are emerging that require their simultaneous usage in a single electrochemical cell. This paper investigates the feasibility and potential drawbacks of such a setup. We use a potentiometric and an amperometric sensor to compare their output signals when they are used individually, as well as when they are combined together with a shared reference electrode. Our results in particular show that potentiometric readings with a shared reference electrode show a high correlation of 0.9981 with conventional potentiometry. In the case of amperometric sensing, the cross correlation of the simultaneous versus individual measurement is 0.9959. Furthermore, we also demonstrate concurrent measurement for potentiometry in the presence of cell current through the design of innovative test systems. This is done through measuring both varying pH values and varying concentrations of H2O2 to showcase the operation of the circuit

SPACEMan: wireless SoC for concurrent potentiometry and amperometry

Abstract: This work describes the implementation of SPACEMan, a wireless electrochemical system with concurrent potentiometric and amperometric sensing that can be utilised for saliva, sweat or point of care diagnostics. This system is designed with the vision of simpler interfaces for biofluid analysis. With a complete system-on-chip including electrochemical sensing, power management and data transmission, conventional interfaces like wirebonds will no longer be required in post-processing steps. The proposed architecture consists of a sensor front-end with four electrodes for concurrent amperometric and potentiometric sensing. This front-end outputs square wave signals mixed together with varying frequencies dependent on the sensed input, with the output type switchable with a state machine. A power management system consisting of a low dropout regulator (LDO) band gap reference (BGR), and a rectifier bridge is utilised for supplying power from an inductive link at 433MHz. Sensor data is transmitted wirelessly to a base station using LSK (Load-Shift Keying). The sensor front-end consumes 18μW, which the power management system more than adequately provides. The core area of the electronics without the coil is a conservative size of 0.41mm 2