This project, like my previous Ultrasonic Sensory Extension Wearable, was designed/created for multiple purposes, a couple of which being: wearable-assisted (See Figure 1) pet care and empathy research and application (specific to animals with vibrissae, see Figure 2) as well as basic sensory augmentation research (specifically, the tactile-to-tactile variety).
Here’s a cursory overview of the components and their functions:
– Two sets of custom built flex sensor whisker devices (total of 8, 4 per side) receive tactile information (bend, flex, etc.) from objects in the user’s immediate environment. The initial voltage/resistance information received by each sensor is then converted to bend angle information (e.g., a bend angle of 10 degrees). This bend angle information is subsequently converted to proportional pulse width modulation output and sent to corresponding vibrotactile displays on the user’s forehead.
– Each whisker sensor has its own SparkFun ProMini 3.3V/8MHz microprocessor that does the transducing/converting. There are two circuits operating on each ProMini (this approach was necessary to alleviate motor EMI disturbance issues). One functions to input whisker information while the other outputs PWM commands to the coupled vibrating mini motor disc located in the vibrotactile display situated on the user’s forehead. Each circuit is powered independently through one of the outputs of a dual output battery.
– Two vibrotactile displays supply tactile stimuli to the user’s forehead. Each motor housed within the two displays is coupled to its own whisker (in the same orientation as the whiskers on the face), functioning in such a way as to reflect the whisker’s bend angle in the form of vibration information. Vibration intensity is proportional to whisker bend angle (e.g., 10-degree bend angle –> 40 units PWM output, etc.).
Thanks to sensory substitution/augmentation phenomena (neuroplasticity; intra-modal plasticity), it’s plausible that, after a given training period, an individual could extend their pre-existing somatosensory apparatus into the realm of these new whisker-like appendages, as blind individuals utilizing tactile-to-vision sensory substitution do (e.g., the use of a walking cane, see Figure 3). It’s plausible that the somatosensory (SS) cortex (mediated through stimulation of forehead skin receptors) could, over time, develop a new “whisker representation” housed somewhere in SS cortex. This type of sensory extension has already been shown in multiple studies (e.g., Sensory Augmentation for the Blind [tactile-to-direction sensory augmentation through the use of a vibrotactile display worn around the waist], Embedding a Panoramic Representation of Infrared Light in the Adult Rat Somatosensory Cortex through a Sensory Neuroprosthesis [although brain-invasive techniques are used here, this supports the concept of cortical re-mapping], etc.). Now let’s make some whiskers!
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