15 May 2020

Sensor-Embedded Garments

Welcome back. Not too long ago, I blogged about a new fabric developed by University of Maryland researchers. Going a step beyond high-tech wicking polyesters, the fabric automatically responds to our skin’s temperature and humidity to either release or trap heat (see post, Thermally Responsive Fabric).

I know, where is it? While we’re waiting patiently for garments of that fabric to reach the market, I thought you might be interested to learn about a new development in textile-based wearable electronics (“e-textiles”). 

Wearable Electronics
Wearable electronics are far from new. These smart electronic devices are worn close to or on the skin, where they may be designed to gauge the wearer’s activity or health measures (e.g., steps walked, heart rate) and perform any number of other functions.
Wearable electronics example–-smartwatch for tracking fitness, monitoring heart rate and a whole lot more
(from www.pcmag.com/reviews/apple-watch-series-5).
E-textile capabilities for collecting health data are advancing rapidly, yet most measure a single modality, such as temperature, from one small area of the body. Enter MIT Media Lab’s new e-textile.

According to a recently published study by the MIT team, their so-called Electronic Textile Conformable Suit (E-TeCS) makes multimodal physiological measurements (currently, temperature, heart rate and respiration) over large areas of the body. What’s more, these garments are custom-fit, breathable and machine washable.

The Electronic Textile Conformable Suit
For the E-TeCS prototype garment, a horizontally striped shirt, the researchers combine long, thin, customizable, conformable electronic devices, including interconnect lines and off-the-shelf integrated circuits, with plastic substrates. These are woven into narrow channels in a polyester-blend, moisture-wicking textile using a high-throughput manufacturing approach.

Long, thin, customizable, conformable electronic devices are woven into narrow channels of striped textile (MIT Media Lab from www.eurekalert.org/multimedia/pub/230022.php).
The channels in which the electronic devices are embedded have small openings toward the body where the sensors are exposed to the skin. E-TeCS is stretchable, similar to a compression garment, to ensure sensor contact between the textile and skin. (A pressure of 2 mmHg is sufficient for accurate skin temperature measurements.) The garments can be laundered with the sensors in place, or the sensors can be removed and transferred to a different garment.

The electronic devices and sensors in the prototype shirt follow the stripes and are connected to the main hub by copper wires inserted vertically through the seams. A computer or smartphone can access the sensors and log their data via wireless communication.

The prototype garment has 31 sensor islands for 30 temperature sensors across the upper body and one accelerometer just below the sternum to estimate heart and breathing rates. Testing during intense physical exercise demonstrated continuous skin temperature measurements to an accuracy of 0.1 C (0.18 F) and heart rate and respiration with a precision of 0.0012 m/s2
Illustration of E-TeCS for distributed on-body sensing with conformable electronic devices along selected stripes, temperature sensors, accelerometer (heart beat and respiration) below sternum and wireless module (MIT Media Lab from www.nature.com/articles/s41528-020-0068-y).
Wrap Up
The research team successfully merged flexible-stretchable electronics with customized knit fabrics to develop the E-TeCS for distributed on-body sensing in vivo. The e-textile shirts can be easily manufactured in different sizes to fit an array of body types.

Looking ahead, the researchers plan to add additional health measures (e.g., blood oxygen levels) and develop other types of garments (e.g., pants). I wonder if they could use the University of Maryland’s thermally responsive fabric. 

Anyway, thanks for stopping by.

Review of wearable technology: en.wikipedia.org/wiki/Wearable_technology
MIT study of tailored, electronic textile conformable suit in npj Flexible Electronics: www.nature.com/articles/s41528-020-0068-y
Article on study on EurekAlert! website: www.nature.com/articles/s41528-020-0068-y

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