A Novel Instrumentation to Investigate the Alternative Tactile Communication through Mechanical Stimulation Using CO₂ Jets

Abstract

This work introduces and discusses a novel instrumentation developed to investigate the psychophysics and cognitive responses of the tactile perception when submitted to a mechanical stimulation using CO₂ jets. The system consists of a CO₂ source that applies gas jets to the skin through an injection needle. It’s pressure and flux can be controlled. The needle is connected to a 2D-plotter which controls its movements on the Cartesian plan, drawing figures, with different sizes and speeds. The performance tests showed a correlation of 0,99726 between the CO₂ pressure and the force produced over the skin, independently of the distance between the needle’s position and the skin, in the range from 1 mm to 15 mm. The prototype may draw 19 characters and 3 geometric figures. It has been used to investigate the skin perception under the fluxtactile stimulation. Preliminary in vivo tests were applied to thirteen volunteers, who were capable to recognize 70% of the characters “drawn” onto their skin. These results suggest that the fluxtactile skin interface can potentially be tested in a blind or deafblind people and serve as basis for future research on tactile alternative communication.