Therma

Therma: Heat Stroke Prevention Sports Bra

(Kiara Torres, Ava Manalo, Yohan Hopgood)

The Problem: Heat stroke is caused by the body overheating, often due to prolonged physical activity in high temperatures. Heat stroke poses significant danger to athletes of all types. There are a few stages of heat injury, with heat stroke being the most serious. It sets in when core body temperature rises past 104° F.

Consequences: Heat stroke requires emergency care. Damage gets worse the longer treatment is delayed, which increases the risk of serious complications or death. Without proper treatment, heat stroke can quickly damage the brain, heart, kidneys and muscles irreversibly. Confusion, agitation, slurred speech, irritability, delirium, seizures and coma can all result from heat stroke. Pulse may significantly increase because heat stress places an extreme burden on the heart to help cool the body.

Our Solution: The Therma Sports Bra is equipped with a smart fabric elastic band which monitors core body temperature and alerts the wearer if they are overheating. Therma offers heat stroke prevention to a broad consumer base; athletes, outdoor workers, motorcyclists, and many more are at risk of heat-related sickness.

Product Design: The elastic band of the sports bra is inlaid with a sensor wire that tracks both skin surface temperature and heat flux. These two data points, along with weather data (acquired via automatic calibration), are used to compute core body temperature.

The system will use an algorithm based on Fourier’s Law of heat conduction to take the data collected from the sensors and arrive at an estimate of core body temperature.

If core body temperature exceeds 102° F, a waterproof LED light on the elastic band lights up and an alert is sent to the user’s smartphone.

The diagram above shows how a textile-based heat flow sensor is created by weaving a thermoelectric wire into a textile substrate. TE wire is composed of two metals, constantan and copper, which form a thermocouple at their junction. These junctions are on both sides of the fabric and voltage is measured when each side of the fabric has a different temperature or there is heat flux occurring.

The system utilizes a heat-flux sensor, amplifier, low-pass filter, ADC, microcontroller, Bluetooth, and skin-temperature sensor. LED indicators flash yellow as the wearer approaches a warning temperature (102° F) and red when approaching a critically dangerous temperature (103° F). Ambient temperature is obtained through local weather data rather than an additional sensor as sports bras are often worn with additional layers on top.

Most electronics will be sewn directly into the garment, allowing the sensors to integrate with the fabric. The battery is housed in a removable back pocket so the garment can be machine washed. Mesh panels are integrated into the front of the bra as well as the straps, encouraging additional airflow and cooling the body.

An app will be paired with the Therma Sports Bra to enable a few key functions: local weather data (which factors into accurate temperature computation), optional user calibration (to account for individualized conditions), core body temperature readings, and overheating alerts.

Interviewing female athletes at Flavet Field gave us insight into the challenges women face on the court. Their comfort and needs are prioritized, and high-level performance is enabled. Our design houses sensor wiring within a satin weave polyester-cotton textile blend, which allows ease of movement and eliminates bulkiness.

Our process: 1) Trip to Flavet Field, where we interviewed athletes about the problems they face

2) Problem selection, solution brainstorming

3) Research on wearable health monitors, heat flux sensors, and smart textile design

4) Learned and created our 3D product model using Clo 3D fashion design software

5) Mapped circuitry for sensors, LEDs, Bluetooth reception, and battery power supply in KiCad

6) Designed an app interface to simulate user experience in Figma

Built With

• clo
• figma
• kicad