From NFC to Biometrics The Tech Inside Smart Rings

By now, we should be able to tell beyond doubt that wearable technology isn’t just another passing fad. Though they’re still far from the gadgets seen in 1980s science fiction, smartwatches are commonplace in most countries, and smart rings are quickly gaining momentum due to their convenience and small form factors.

But the small package raises some questions. How good can they really be, and what are they capable of? What technology is used in a smart ring?

Close-up view of a smart ring displaying its internal technology

Key Takeaways

  • Smart rings contain the same basic sensors you will find in smartphones and smartwatches and some additional ones that focus on your health.
  • They connect to other devices using Bluetooth and NFC.
  • You can interact with smart rings using touch controls and sliding gestures.
  • Output happens through haptics, LEDs, or (in a few cases) small screens.
  • Their tiny processors are energy-efficient, so small batteries suffice.

Miniaturized Sensors: The Heart of Smart Rings

Smart rings consist of many of the same sensors that smartwatches (and even smartphones) have, but they are usually much smaller to fit into the compact size of a smart ring. The most common sensors are:

  • Accelerometers and gyroscopes: These two sensors work together to record movement, direction, and rotation. Smart rings use them to calculate your steps, general motion, and activity to feed through to your smartphone to log the data in your health and fitness apps.
  • Temperature sensors: Some smart rings have built-in temperature sensors that can monitor the wearer’s body temperature, the ambient temperature, or both.
  • Blood oxygen sensors: These sensors use red and infrared LEDs to measure peripheral oxygen saturation (SpO2). Instead of spot-checking for these readings like smartwatches do, some smart rings (like the Oura Ring Gen 3) take continuous readings while you’re sleeping.
  • Electrodermal Activity (EDA) sensors: These sensors measure changes in the electrical properties of your skin due to the activity of your sweat glands. In other words, it measures your stress levels with over 94% accuracy.
  • Heart Rate Monitors: Smart rings contain sensors to measure both Heart Rate and Heart Rate Variability (HRV). This is useful for detecting the calories your burn but can also be invaluable for people with heart problems. There are currently two common types of heart rate monitors.

    The first is an electrical heart rate monitor, which is similar to the ones found in a chest strap or electrocardiogram (ECG). It is too large to fit in a smart ring, at least using current technology.

    The second type is optical and uses Infrared Polyplethysmogram (PPG). These sensors are often found in smartwatches and are becoming more common in smart rings, too. Both heartrate monitors give early warnings to indicate possible heart diseases or cardiovascular disorders.
  • Environmental sensors: Some smart rings also include sensors that track external factors rather than your physiological data. A notable example is a UV radiation sensor that tracks your exposure to sunlight, which helps prevent sunburn and ensures you get sufficient Vitamin D levels.

Here, we can see a significant difference between smartwatches and smart rings. A smartwatch is intended to be an extension of your smartphone, offering notifications and the ability to make calls and listen to music. Health and fitness tracking is often just a bonus.

Smart rings, on the other hand, have health and fitness metrics at their core, with additional functionalities added as a bonus. This makes them invaluable in the medical field. We will look at this aspect in detail in a moment.

Wireless Connectivity

Smart rings aren’t meant to be standalone devices. Without a smartphone connection, they are nothing more than reasonably expensive jewelry, so they must be able to handle wireless connectivity.

Most smart rings support two wireless connectivity formats:

  • Bluetooth: Just about every smart ring incorporates some Bluetooth standard, though the versions will differ from model to model. Bluetooth connections allow the smart ring to connect with your smartphone. That’s how they deliver your notifications and call alerts and sync their sensor data with the apps on your phone.
  • NFC (Near-Field Communication): NFC is the same technology you use when you tap your smartphone or smartwatch against a card machine to pay for something. Some smartphones can also use NFC to share data or files.

    A smart ring uses NFC for similar purposes. If the ring supports payments, you can tap your ring against a card machine instead of your smartphone or smartwatch. Some smart rings also use their NFC capabilities to enable seamless Bluetooth pairing with smartphones.

    There are even smart rings that will let you program their NFC capabilities for security or access control functionality or even to unlock your smartphone or tablet automatically.

Compact Batteries

A device as small as a smart ring can’t house a large battery. The good news is that it doesn’t have to. Smart rings accommodate tiny high-capacity batteries that can last for days on a single charge because of how energy-efficient the average smart ring is. Most smart rings come with wireless charging stations to save the space needed for a charging port.

Tiny Microprocessors

A smart ring is a tiny computer, which means it must contain a processor that controls all the device’s operations. These processors are small and not nearly as complex as those found in larger devices. Still, the plus side is that this also makes them energy-efficient and not overly susceptible to damage from high temperatures.

Touch Controls

Older smart rings contain tiny buttons, but most modern models come equipped with touch-sensitive input sensors, which means you can control your smart ring by touching certain parts. Some models incorporate sliding and micro-rolling gestures, which means you can control its functionality by sliding your fingers over the ring in specific ways or changing its position.

Haptic and LED Output

Like your smartphone and smartwatch, most smart rings are equipped with haptic motors to emit subtle vibrations as a form of output or feedback. They vibrate when notifications arrive or to confirm when you’ve changed a setting, and different vibrations or pulses have different meanings.

Some of the more advanced smart rings have built-in LEDs to give some form of visual feedback, though these models still make extensive use of haptic feedback, too.

LED Displays

LED displays are pretty rare on smart rings because they require more power and make the ring bulkier. But there are some more expensive smart rings out there that contain some form of visual display or screen. Logically, the screens are tiny, if they exist at all, but they come in two basic form factors.

The first is a wide, narrow screen that fits inside the band itself. These screens can actually show a surprising amount of information, such as the time, temperature, or the number of steps you’ve walked. Some even display rudimentary menus that you can use to navigate through the ring’s options, similar to the screens that old cellular phones had in the 1990s.

Other smart rings have larger screens with more of a square shape. The ring resembles a signet ring or a smaller version of a smartwatch to accommodate the screen. These screens also display the temperature, time, or step count.

Smart rings with screens aren’t as common as those without screens, and they tend to be more expensive with shorter battery life. They are also less inconspicuous than other smart rings since the screen can quickly draw attention to the fact that it’s not a regular ring.

Water Resistance

Like smartwatches, smart rings are designed to cater to athletes and other active people. This requires a high level of water resistance, which you will often find in popular models.

For example, the Amovan Smart Ring has an IP68 rating and is water-resistant up to 100 meters. The Oura Ring has an IPX8 rating and can also handle depths of up to 100 meters. You can wear most smart rings while it’s raining, in the shower, or when you’re going for a swim. You can wash your hands with them on, and they should be fine on warm, sweaty days.

Remember that you will have to check the water resistance rating of any model you consider buying since not all smart rings are equal in this regard.

Health and Fitness Tracking

We’ve seen that smart rings have multiple sensors for tracking your health and fitness. But they also boast advanced algorithms that decode the data to provide users with comprehensive insights into their well-being.

  • Sleep Tracking: Through an intricate fusion of movement and heart rate data, smart rings monitor the various sleep phases you go through—light, deep, and REM. This comprehensive analysis allows users to quantify the duration and understand the quality of their sleep.
  • Activity Tracking: Activity tracking is about more than just counting steps. Have you ever been frustrated that your smartwatch doesn’t track your gym routine without plenty of manual input? Smart rings solve this (to some extent) by meticulously monitoring your daily activities and providing users with recovery scores.

They consider factors like intensity, duration, and frequency of physical activities, offering detailed insights into the overall impact on your health and well-being.

  • Heart Health Monitoring: Smart rings offer continuous heart rate monitoring and real-time insights into your cardiovascular health. They include Heart Rate Variability (HRV) analysis, measuring variations between successive heartbeats. This provides a holistic view of your heart health and indicates your body’s ability to manage stress.
  • Early Illness Detection: Smart rings are at the forefront of proactive health monitoring, utilizing data such as skin temperature and HRV shifts to detect potential signs of illness. They recognize deviations from your individual baseline values and alert you to subtle changes that may indicate the onset of health issues.
  • Women’s Health Features: Smart rings incorporate features that cater to the unique physical needs of women, such as period prediction and cycle insights. They empower users with a deeper understanding of their reproductive health.
  • Stress Monitoring: Stress affects our overall health in various ways. Smart rings can assess stress levels by analyzing physiological signals and offering a tangible representation of the mind-body connection. Recognizing patterns in your heart rate, sleep quality, and activity levels provides insights that can help you manage and mitigate stress effectively.


In the ever-changing landscape of wearable technology, smart rings have emerged as a stylish and functional accessory. Packed with an impressive array of sensors, connectivity options, and compact components, these tiny devices are revolutionizing how we benefit from and interact with technology.

As advancements continue, we can only anticipate more sophisticated features and capabilities being packed into these unassuming yet powerful rings that adorn our fingers. It seems the future is literally at our fingertips.