9.3 Artificial Biosignal Interfaces

The interfaces inspired by human skin act as a bridge between prosthetic limb and nervous

system. To synchronize the work of sensors present on a prosthetic limb and nervous

system, an artificial path for signal transmission is needed for a prosthetic interface. The

transmission of these biosignals is performed by encoding techniques. These techniques are

inspired by the synaptic transmission of action potentials and analog to digital conversion.

9.3.1 Signal Encoding/Transmission in the Nervous System

Biosignals are collected, transformed, and processed by the nervous system in the human

body. Different receptors like thermal receptors, mechanoreceptors, and nociceptors receive

the physical stimuli that are encoded into electrical signals. Afterward, these electrical

signals are converted into action potentials by sensory neurons. Different types of stimuli

are sensed by various types of sensory receptors. Temperature, pressure, and smell are

sensed by thermoreceptors, mechanoreceptors, and olfactory receptors, respectively.

Specific receptor converts the stimulus-response into action potential with specific codes.

The intensity of the signal from receptors is represented as a frequency of action potentials

after conversion into digital pulses, accordingly.

9.3.2 Signal Encoding in Electronic Skin Systems

External stimuli are converted into electrical quantities like current, voltage, capacitance,

and resistance in an electronic skin. A pulse-like potential that contains the information of

FIGURE 9.5

Artificial prosthetic hand synthesized on gloves to mimic human-like features. Adapted with permission [ 29].

Copyright 2019, Springer Nature.

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