The advent of sensor technologies and the resulting abundance of information together with modern advanced processing capabilities makes improving human lives via human augmentation technologies ever more appealing. To establish a new effective form of human-machine-communication (M2HC) for augmentation, this dissertation explores non-invasive peripheral nerve stimulation via electrotactile waveforms. This dissertation conducts extensive convergence research between the fields of psychology, electrical engineering, neuroscience and human augmentation and established innovations to create distinct sensations that can be utilized as iconic electrotactile M2HC. Existing electrotactile stimulation models deliver a limited range of distinct sensations, making iconic communication challenging. To address this issue, we created a software/hardware infrastructure, including novel electrotactile electrode arrays and improved stimulation circuitry, that allows for rapid prototyping and testing various electrotactile innovations. We created a model for electrotactile waveform generation (MEWS) wherein a train of high-frequency electrotactile pulses is shaped into electrotactile waveforms through a multi-layer on-off-keying modulation forgoing the need for constant frequency recalibration and making painful sensations less likely to happen. Using MEWS, we conducted multiple human trials on 15 volunteering participants stimulating a total of ~6000 electrotactile sensations which led us to create 13 distinct electrotactile waveform with an accuracy of 85.4%. To increase the number of messages that can be delivered by electrotactile stimulation, a model for creating varying electrotactile waveforms (MOVES) was created based on linguistic concept of phonemes and taking a semi-heuristic approach to creating electrotactile waveforms. Using MOVES we conducted multiple human trials on 21 volunteering participants stimulating a total of ~5000 electrotactile sensations. Our human trials proved that MOVES was able to create 24 distinct sensations with an accuracy of 89% that can be used to convey messages through iconic communication and has the potential to expand further beyond the 24 messages. The number of messages delivered by MOVES pentuples the best recorded number of distinct electrotactile sensations in literature.
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