Author: Shannon Deale
Deale, Shannon, 2019 Electrical stochastic resonance system : design of a miniaturised electrical stochastic resonance device , Flinders University, College of Science and Engineering
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The term stochastic resonance (SR) has been commonly used to describe the positive effect the presence of a level of randomised signal (noise) has on the performance of a non-linear (threshold-based) system. The somatosensory system is a threshold-based system that is essential to everyday life for most people and allows people to independently and effectively traverse or interact with the environment with little conscious effort. The sensitivity of the somatosensory system is known to deteriorate due to advanced age or certain neurological diseases. The objective of this project was to design and develop a prototype system that can deliver a random electrical stimulus (in the form of pseudo-white Gaussian noise) to sites on the body via electrodes to facilitate SR effects in enhancing the sensitivity of the somatosensory system.
This project was undertaken to improve upon a previous prototype device of similar function that was considered too big to be sufficiently portable and did not have high enough voltage output to sufficiently deliver 1mA through typical skin impedance. The project intended to yield a device that had a much higher voltage output as well as being much smaller (increasing wearability). It was determined that a completely new design would best facilitate these improvements. Working towards this aim the objectives of this project involved the development of electronic circuitry that included a high voltage power supply unit (HVPSU), high voltage current pump (HVCP), microcontroller, digital-to-analogue converter, level shifter and a wireless transmitter/receiver. Additionally, the project required using software to develop a graphical user interface (GUI) and signal generation software to produce the pseudo-white Gaussian noise signal.
Several milestones towards the objective of this project have been achieved. The design of the electronic circuitry, including the HVPSU, HVCP and control circuitry, that realises the concept for the device has been completed. Printed circuit boards (PCBs) have been designed for the HVPSU and HVCP based on thorough breadboard testing of the two circuits (the results of which matched data reported for similar circuits documented in literature), making them ready for immediate manufacture. All the components for the PCBs have been identified and budgeted for. The design considerations and testing for the control circuitry has also been completed, ready for the design of a PCB. Finally, the main functional components of the software have also been developed. Significant work has been completed across all the major components within this system. All that remains is to combine them into a functioning prototype. The long-term aim is that the system will be used in a clinical research setting enabling the investigation of potential benefits from prolonged use of SR stimulation, hopefully leading to improved function and quality of life.
Keywords: electrical, stochastic, resonance, miniaturised, portable, balance, postural sway, noise
Subject: Engineering thesis
Thesis type: Masters
Completed: 2019
School: College of Science and Engineering
Supervisor: Kenneth Pope