Researchers from the Massachusetts Institute of Technology (MIT) and the Southern University of Science and Technology (SUSTech) in China recently designed an innovative, flexible sensor to create a tactile-sensing glove. The glove detects slight, rapid changes in pressure at the fingertip using human sweat as part of the sensor’s electrode capacitor.
The research team based its technology on existing humidity sensors. Capacitors in these standard systems sandwich a rubbery “dielectric” layer between two metal electrodes. Electric charges move between the electrodes through the dielectric material. The more humidity is present, the more ions the dielectric layer absorbs, affecting the amount of charge between the electrodes. Such sensors can also measure pressure, because squeezing causes the diametric layer to release ions, thus changing the level of charge.
To reduce the bulk of the standard dielectric material, the team designed a capacitor that allows human sweat to become the conductive layer between thin electrodes laying side-by-side. The team built the thin, flexible electrodes by spraying carbon cloth with gold filaments, then installing a network of these tiny gold plates within a silk glove. If pressure affects one electrode, it changes the ion level between nearby electrodes. Even very light pressure such as gently rubbing the fingertips together can cause changes in the electrode charge.
By quantifying those changes, the team measured pressure patterns during several motor activities, such as gripping a glass beaker and holding a balloon. Identifying tactile patterns and integrating the glove with a user interface could have many healthcare applications. For example, stroke patients could wear the glove as part of rehabilitation training to regain fine motor control. The prototype glove can already measure pulse rate; it’s likely it could track blood pressure and other biometrics with high accuracy.
The MIT and SUSTech team published their research in Nature: Communications.
