Melexis - Medical Technology | Issue 51

Contactless thermometry in wearables

enable accuracy, repeatability and miniaturization

Wearables with medical functionalities are rapidly becoming essential tools for monitoring, prevention and detection. Registering the correct skin temperature is a crucial element in this evolution. In order to do so, accuracy, repeatability and miniaturization are of utmost importance. This is where Melexis contactless temperature sensors come in as they are the only factory calibrated solution on the market with medical grade accuracy (+/- 0.2 °C).

Advantages wearable and remote bio-sensing

Non-invasive
Fast analysis
Cost advantage

The skin plays an important role in the human body’s thermoregulation. Registering a raised skin temperature has many interesting use cases. Fertility tracking, infection detection, stress monitoring, sleep analysis… Continuous monitoring of the skin temperature enables medical wearables to detect trends which make them ideal for prevention. Of course this is only possible when measurements are accurate and repeatable.

Typical applications for MLX90632

contactless temperature sensors:

SMART PATCHES
SMART WATCHES / BRACELETS
EARBUDS
SMART GLASSES

Which can be used for:

REMOTE PATIENT MONITORING
STRESS MONITORING
HEALTH MONITORING
ACTIVITY TRACKING

Contact or contactless?

Why contactless? Contact thermometry is under the influence of different parameters like pressure or friction. As non-contact thermometry relies on infrared radiation, it avoids this pitfall. This gives your wearable the advantage of repeatability. Different measurements are not influenced by external parameters so you get consistent results.

No thermal shock

So is there a downside to contactless temperature sensing? Yes, there is one: thermal shock. The direct surrounding of a temperature sensor has influence on the temperature registration, even when not in the field-of-view of the sensor. Melexis added a compensating mechanism in the sensor to overcome this problem and create thermostability. This can be tested by using a heat gun on the MLX90632 sensor. In the graph you can see the results of this test. This is how Melexis obtains medical accuracy in contactless temperature measurement.

Optimize your power budget

Since the contactless temperature sensor MLX90632 caters wearables, power consumption is a crucial element. If your battery runs out of juice, there will be no measurements. Thanks to an open source software driver, you can easily control the interval between the measurement points and thus the power consumption.

Easy to integrate

Thanks to Melexis’s intensive know-how we managed to bring the smallest SMD (Surface-Mount Device) medical-grade solution on the market. This miniaturization makes the difference in the design of your wearable. The combination of miniaturization, medical accuracy and thermostability is an unseen combination in the world of temperature sensors for wearables. Another benefit is the use of open source software. This facilitates the integration with the most popular development microcontrollers.

Working on a wearable project with contactless thermometry?

Let Melexis help you to get a competitive advantage.

You are developing a medical wearable? You already have a wearable but want to include a contactless temperature sensor? Use our technological know-how and let Melexis assist you with the integration of the award winning MLX90632 sensor in your design. Contact Joris Roels, Marketing Manager Sense & Light for all your questions and to get technical advice on the integration of thermometry in your wearable project. This is the only case where contact is better than contactless. Get your competitive advantage now!

Get technical advice on thermometry integration