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The Brain Inside Your Watch: A Look at the Advanced Technology of Smart Watches

Updated: 2 days ago

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Smart watches are becoming increasingly smarter and more sophisticated, with many advanced features that can track a range of health metrics, provide notifications, and even make phone calls, alert emergency services, and send text messages.

I, personally, wear mine every time I workout, and if I know I will be somewhere that I won't be able to be on my phone much like at an event, gardening, or shopping.

Two of the most widely known capabilities of smart watches are notifications and apps.

Smartwatches can provide notifications for incoming calls, text messages, emails, and social media alerts. Some models also allow you to control music playback and even pay for purchases using contactless payment systems like Apple Pay or Google Pay. Many now have a range of apps available, which can be used for everything from tracking your menstrual cycle to controlling smart home devices.

Many smartwatches now include sensors that can track heart rate, steps taken, and even sleep patterns. Some models also have built-in GPS, altimeters, and barometers, which can be used to track workouts and other outdoor activities.

I wondered - how is the watch able to do everything it does. What was inside my watch? Well, let's take a look inside.


First up, is something called an altimeter. An altimeter is a sensor that measures altitude, or the height of an object above a specific reference point, usually sea level. In a smartwatch, an altimeter is a sensor that measures changes in air pressure to determine changes in altitude. This can be useful for tracking elevation gain during activities like hiking, skiing, or climbing, as well as for monitoring changes in atmospheric pressure, which can be an indicator of changes in weather.

The sensor is typically located within the watch case and uses a barometric pressure sensor to measure changes in air pressure. It then uses this information to determine the wearer's altitude and display it on the watch face or within an app. Some smartwatches with altimeters also include GPS sensors, which can provide more accurate elevation data by combining barometric pressure measurements with GPS data. This can be useful in areas with significant changes in elevation, where barometric pressure alone may not provide accurate altitude data.

There's also a few other types of sensors such as:

  • Gyroscope: This sensor detects rotational movement and is used to track activities like cycling and swimming.

  • Ambient light sensor: This sensor adjusts the brightness of the watch screen based on the surrounding lighting conditions.

  • Skin temperature sensor: This sensor measures the wearer's skin temperature and can be used to track changes in body temperature.

Next, is something a little more advanced. Some smartwatches have advanced health monitoring features like electrocardiogram (ECG) readings, blood oxygen monitoring, and skin temperature sensors, which can be used to detect a range of health issues.

I use mine all the time!

a smart watch with apps flying out of it

The ECG feature in a smartwatch measures the electrical activity of your heart to help detect irregular heart rhythms, such as atrial fibrillation (AFib).

Yes, we run on electricity. So wild. But before I get existential, let's continue.

AFib is a common condition that can increase the risk of stroke and other complications if left untreated. To take an ECG reading on a smartwatch, the wearer typically places their finger on a specific spot on the watch face or touches a metal button on the side of the watch. The watch then measures the electrical activity of the heart and analyzes the rhythm to detect any irregularities. The results are displayed on the watch face or within a companion app on the wearer's phone.

Health technology devices really are amazing. My watch reminds of this every time I take a reading.

However, it looks like Artificial Intelligence isn't going to save us all from our own demise just yet. It's not that sophisticated.

Okay, let's get to some computer techie stuff...

spongebob with rainbow

Smartwatches are powered by processors, which can range from basic processors for simpler models to more advanced processors for higher-end models. These processors allow the smartwatch to perform tasks like running apps and tracking health metrics.

Some of the most common types of processors used in smartwatches are:

  • Qualcomm Snapdragon: This is a popular processor used in many Android-based smartwatches, including the Samsung Galaxy Watch and many Wear OS devices. The Snapdragon processors are known for their efficiency and performance.

  • Apple S-series: This is a family of processors used in Apple Watch models. The S-series processors are designed specifically for the Apple Watch and offer high performance and energy efficiency.

  • Samsung Exynos: This is a processor used in some Samsung smartwatches, including the Galaxy Watch 3. The Exynos processors are known for their powerful performance and energy efficiency.

  • MediaTek: This is a processor used in some budget smartwatches. While MediaTek processors are not as powerful as some of the other processors listed here, they can still provide adequate performance for basic smartwatch functions.

  • TI OMAP: This is a processor used in some older smartwatches, including the original Samsung Galaxy Gear. While these processors are not as powerful as some of the newer processors, they can still provide adequate performance for basic smartwatch functions.

Let's talk about the display screen.

OLED (Organic Light Emitting Diode) and LCD (Liquid Crystal Display) screens are two types of display technologies used in smartwatches.

  • OLED screens use organic compounds that emit light when an electric current is applied. Each pixel on an OLED screen emits its own light, allowing for brighter and more vivid colors and deeper blacks than LCD screens. OLED screens are also more power-efficient than LCD screens because they don't require a backlight, which can consume a lot of power. This means that OLED screens can help conserve battery life in a smartwatch.

  • LCD screens, on the other hand, use a backlight to illuminate the display. This means that all the pixels on the screen are lit up, even when displaying darker colors, which can result in less contrast and deeper blacks than OLED screens. However, LCD screens can be more power-hungry than OLED screens, especially if the backlight is set to a high brightness level.

In terms of performance, both OLED and LCD screens can provide clear and detailed visuals in a smartwatch. OLED screens are often preferred for their bright colors, deep blacks, and energy efficiency, while LCD screens are sometimes preferred for their more natural-looking colors and wider viewing angles.

The choice between OLED and LCD screens often comes down to personal preference and the specific needs of the smartwatch.

We already know smartwatches can call, text, and some even have a "walkie-talkie" feature.

So how does the watch connect to wireless?

Smartwatches typically include Bluetooth and Wi-Fi connectivity, which allow them to connect to your phone and other devices.

Most smartwatches use Bluetooth to connect to a smartphone or other device. The watch can be paired with a smartphone using Bluetooth, which allows the watch to receive notifications, control music playback, and access other features. Others can connect to Wi-Fi networks, allowing them to access the internet, receive notifications, and stream music without the need for a smartphone connection. Wi-Fi-enabled smartwatches can also connect to other devices on the same network, such as speakers or other smart home devices.

The Apple Watch has a built-in cellular connection, allowing them to make calls, send messages, and access the internet without needing to be connected to a smartphone or Wi-Fi network. These watches require a separate cellular plan and a SIM card, similar to a smartphone. And then there is Near Field Communication (NFC) to connect to other devices, such as contactless payment terminals or other NFC-enabled devices. This allows the user to make payments, unlock doors, or access other features using their watch.

And the batteries? Who knew there were so many different kinds? Not me!

Smartwatches have rechargeable batteries that can range in size depending on the model. Battery life can vary widely depending on the model and how it's used.

  • Lithium-ion: This is the most common type of battery used in smartwatches. Lithium-ion batteries are lightweight, rechargeable, and have a high energy density, which means they can store a lot of power in a small space.

  • Lithium-polymer: This type of battery is similar to lithium-ion batteries but has a different electrolyte composition. Lithium-polymer batteries are often used in smaller devices like smartwatches because they can be shaped more easily than lithium-ion batteries.

  • Silver oxide: This type of battery is commonly used in traditional watches, but some smartwatches use them as well. Silver oxide batteries are small and long-lasting, but they have a lower energy density than lithium-ion or lithium-polymer batteries.

  • Nickel-metal hydride: This type of battery is less common in smartwatches but is sometimes used in hybrid smartwatches that have analog watch faces. Nickel-metal hydride batteries are rechargeable and have a high energy density, but they are less efficient than lithium-ion or lithium-polymer batteries.

  • Solar: Some smartwatches use solar-powered batteries, which can charge the watch using light from the sun. Solar-powered watches are typically less power-hungry than those with traditional batteries, but they may require more frequent charging in low-light conditions.


The smartwatch operating systems also vary.

Apple's watchOS, Google's Wear OS, and Samsung's Tizen OS provide their interface and functionality through a variety of operating systems (OS), depending on the brand and model of the watch.

  • watchOS: This is the operating system developed by Apple for its Apple Watch. It is a proprietary operating system that is designed to work seamlessly with Apple's other devices, such as the iPhone and iPad.

  • Wear OS: This is the operating system developed by Google for smartwatches. It was originally called Android Wear, but it was rebranded as Wear OS in 2018. Wear OS is designed to work with both Android and iOS devices.

  • Tizen: This is the operating system developed by Samsung for its Galaxy Watch series. Tizen is a Linux-based operating system that is designed to work with Samsung's other devices, such as smartphones and tablets.

  • Fitbit OS: This is the operating system developed by Fitbit for its smartwatches, including the Fitbit Versa and Fitbit Ionic.

  • Garmin OS: This is the operating system developed by Garmin for its smartwatches, including the Garmin Vivoactive and Garmin Forerunner series.

LAST, and my LEAST favorite feature.

Voice assistants...

Voice assistants like Siri or Google Assistant, allow you to perform tasks using voice commands, like setting reminders, sending texts, and making phone calls without touching your phone.

"Allegedly" (my quotes) – Voice assistants on smartwatches such as Siri on Apple Watch and Google Assistant on Wear OS watches are not always listening. Instead, they are activated by a specific wake word or phrase such as "Hey Siri" or "OK Google". The voice assistant is designed to listen for that specific phrase, and only starts processing your request once it is activated.

Call me skeptical.

When the voice assistant is activated, the microphone on the smartwatch is turned on and it starts listening for your request. Once you've made your request, the voice assistant processes it and provides a response on the smartwatch's screen or through the watch's speaker or haptic feedback. Some smartwatches may have an "always-on" feature that allows you to activate the voice assistant by pressing a button or through a gesture, without having to use a wake word. This feature may come at the expense of battery life and is not always enabled by default.

tldr; I like the idea of smartwatches, and I own an Apple Watch, but I still prefer my analog and digital watches over smartwatches any day.

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