Apple’s AI based odor sensor technology could transform future Apple Watch Health and Safety offerings

Apple Watch odor sensors

Apple’s thinking around a pioneering way to explore sensors came to light with the release of a newly approved patent this week.

The technology describes an ionic liquid sensor in a portable communication device such as an Apple Watch, which can be tuned for sensing a smell associated with a chemical species. 

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The processing circuit further includes an artificial intelligence engine to enhance the smell recognition capabilities of the device.

What is the purpose of this odor sensor technology?

Smart portable communication devices today (e.g., smartphones and smartwatches) can interact with the user through some of the human senses such as vision, hearing, and touch. 

There are electronic devices that can detect an analyte in fluids (e.g., liquids, gases, and vapors) with the help of pattern-recognition. 

However, there are no portable communication devices that can mimic users’ senses for smell and taste.

The ability to smell various flavors when combined, for example, with photo recognition can open a new horizon to smart device applications.

The new applications may be in a number of areas including health, safety, security, networking, and other areas as per the patent.

For example, in the health and safety areas, a smell-enabled (e.g., e-nose) smart communication device may be able to alert users about dangerous levels of gases such as carbon monoxide, natural gas and other toxic and/or hazardous gases, or measure compounds in human sweat and alert the user about his sugar levels.Apple Watch

How would the odor sensor technology work?

Portable devices such as the Apple Watch will have embedded ionic liquid sensors.

Each ionic liquid sensor is contained in an enclosure formed by micro-electro-mechanical system (MEMS) structural elements and a surface of a semiconductor chip including the processing circuit. 

The ionic liquid-based sensors are the key

Ionic liquid-based sensors have been used in research labs for motion monitoring, healthcare, and virtual reality applications.


They have been used in the detection of illegal compounds such as Fentanyl in the past.

The enclosure further includes an air-permeable layer that covers the MEMS structural elements. 

Semiconductor chip further includes a heater configured to raise temperatures of ionic liquid sensors to facilitate the reversal of the bonding of the chemical species to the ionic liquid sensors.

Each of the one or more sensors includes an inherent variable resistance and an inherent variable capacitance, wherein values of the inherent variable resistance and the inherent variable capacitance depend on the smell associated with the chemical species. 

The idea is to make each sensor out of different ionic liquid material with a different absorption coefficient so it can be used for detection for various flavors/odors.

Signal Processing and enhancement using Artificial Intelligence (AI)

Odor sensor in Apple Watch

The processing circuit further comprises an analog multiplexer, a low pass filter, and an analog-to-digital converter (ADC) and a digital signal processing circuit to preprocess the output signals from one or more sensors for analysis by the artificial intelligence engine. 

The artificial intelligence engine is configured to enhance the smell recognition capabilities of the device based on smell information stored in a memory. 

The smell information stored in the memory is associated with a number of applications including at least one of aviation safety, hazardous gas detection, spoiled food material detection, blood sugar, body odor detection, and other health applications.

Wearable flexible sweat sensors for healthcare monitoring have seen numerous research in the last few years. Glucose Oxidase levels in sweat can be used to calculate blood sugar.

Wrap up

In Summary, the area of exploring odor sensing using ionic sensors is not new. It has been used by researchers in other applications.

What is interesting here is that Apple is thinking of embedding the technology into portable devices such as the Apple Watch or the iPhone in the future.

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Sudz Niel Kar
I am a technologist with years of experience with Apple and wearOS products, have a BS in Computer Science and an MBA specializing in emerging tech, and owned the popular site AppleToolBox. In my day job, I advise Fortune 500 companies with their digital transformation strategies and also consult with numerous digital health startups in an advisory capacity. I'm VERY interested in exploring the digital health and fitness-tech evolution and keeping a close eye on patents, FDA approvals, strategic partnerships, and developments happening in the wearables and digital health sector. When I'm not writing or presenting, I run with my Apple Watch Ultra or Samsung Galaxy Watch and closely monitor my HRV and other recovery metrics.


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