A ‘skin’ that tracks movement

Test of flexibility: Scientists Chandramouli Subramaniam, left, and Mihir Kumar Jha display

the wearable gesture tracking device. | Photo Credit: Special Arrangement

IIT–Bombay team produces a wearable device that may help stroke survivors

A thin, light, wearable gesture-tracking device that behaves like a second skin and is able to

precisely detect mechanical movements such as bending and stretching of the joints of the

hand — fingers, knuckles and wrist — has been developed by researchers at the Indian

Institute of Technology (IIT) Bombay.

The device can find applications in physiotherapeutic recuperation of stroke patients,

personalised point-of-care health monitoring systems, and robotics.

Accurate measurement

While commercially available activity trackers can estimate parameters such as number of

steps taken and calories burnt, this device can accurately measure the amount of motion

taking place in all the three joints during any activity or gesturing, the researchers said.

The device is capable of instantaneously detecting movements and is quite sensitive — it can

detect variations of about 2 mm during stretching and about 5 degrees during bending in all

the three joints.

What makes the device particularly unique is its ability to track the amount of bending of

individual joints and distinguish the differing extent of movement occurring simultaneously

in all the three joints of the hand.

“The device can be directly put on skin, on gloves or any artificial surface like robots,” says

Prof. Chandramouli Subramaniam from the Department of Chemistry at IIT–Bombay. The

performance and sensitivity of the device is not compromised by humidity or temperature.

Across all joints

“Though we tested the device on the three joints of the hand, it can be used for tracking the

movement of any joint in the body,” says Prof. Subramaniam.

The researchers used a polymeric film as a matrix in which carbon nanotubes are uniformly

distributed. When the matrix is stretched or bent, the way the carbon nanotubes are connected

changes. This produces a change in the electrical pathway across the device which is

measured as change in resistance.

Unlike other devices which use metallic electrodes, the one developed by the IIT–Bombay

team uses the same carbon nanotubes for electrodes. “Metal electrodes are more prone to

failure and fatigue and are uncomfortable when used directly on skin. So we made the

electrodes by coating a cotton thread with carbon nanotubes,” says Priya Rathi, the first

author of the paper.

Studies will be carried out on healthy individuals and those with arthritis to understand the

difference in movement of joints. Later, those with early-stage arthritis will be enrolled and a

longer-duration study will be conducted, says Prof. Subramaniam.

The results of the research were published in the journal ACS Omega.

Source : The Hindu