Mechanomyography (MMG) has been proposed as a control modality for alternative access technologies for individuals with disabilities. However, MMG recordings are highly susceptible to contamination from limb movements. Pressure-based transducers are touted to be the most robust to external movement although there is some debate about their optimal chamber geometry, in terms of low frequency gain and spectral flatness.
To investigate the question of preferred geometry, transducers with varying chamber shapes were designed, manufactured and tested. The best performance was achieved with a transducer consisting of a low-frequency MEMS microphone, a 4 micron thick aluminized mylar membrane and a rigid conical chamber 7 mm in diameter and 5 mm in height.
Furthermore, microphone-derived MMG spectra were found to be less influenced by motion artifact than corresponding accelerometer-derived spectra. However, artifact harmonics were present in both spectra, suggesting that bandpass filtering may not remove artifact influences permeating into MMG frequency bands.
| Identifer | oai:union.ndltd.org:TORONTO/oai:tspace.library.utoronto.ca:1807/31389 |
| Date | 19 December 2011 |
| Creators | Posatskiy, Alex |
| Contributors | Chau, Tom |
| Source Sets | University of Toronto |
| Language | en_ca |
| Detected Language | English |
| Type | Thesis |
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