Collections > Electronic Theses and Dissertations > A Device for Vibrotactile Stimulus Delivery in Magnetic Environments
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Currently, the most accurate and precise method to deliver a vibrotactile stimulus is via the use of a voice coil actuator (VCA). Because the VCA uses a coil of wire contained in a magnetic field, this system cannot be used in imaging systems that rely on the use of magnetic fields. Thus, an alternative device is needed that can be used to deliver tactile stimuli in magnetic fields such as those generated by Magnetic Resonance Imaging (MRI) and Magnetoencephalography (MEG) systems. For this reason, a novel stimulus device was designed to deliver vibrotactile stimuli with variable amplitudes (up to 2mm peak-to-peak) and frequencies (ranging from 25Hz up to 200Hz) as these are the optimal stimuli for evoking activity in somatosensory cortex. To accomplish this, a system using a high-voltage op-amp and piezoelectric actuator was designed to deliver precise and accurate stimuli to the skin without being impacted by the surrounding magnetic field. Additionally, the device was designed with the intention of keeping all sensitive electronics at a safe distance from the magnetic imaging systems.