Investigating Distinct Intensity Levels in Electrotactile Machine-to-Human Communication

The field of human augmentation (HA) has received an increased research focus from neurotechnologists due to advancements in information sensing and processing capabilities. Despite advancements in HA, machine-to-human communication (MHC) is still reliant on visual and auditory pathways. Electrotactile stimulation of peripheral nervous system can be used as an alternative pathway for MHC, contingent upon consistently distinct electrotactile sensations can be created. A person can be trained to associate a distinct electrotactile sensation with a specific information cue, effectively creating an alternative pathway for MHC. A technique for creating distinct electrotactile stimulation is modulating the intensity of the observed electrotactile waveform. Among the possible techniques to modify intensity, this paper investigates the possibility of manipulating a train of high-frequency pulses with the duty cycle of a superimposed mask. Furthermore, this paper explores the limits of human ability to distinguish intensity levels created through manipulation of high-frequency pulses. This paper found that using the presented frequency manipulation technique makes it possible to reliably create 3 intensity levels with an accuracy higher than 85%.