Beyond the wrist
Watches and bands remain the most familiar wearables, but companies have tried many other shapes. Each new form is an attempt to fit sensors or a computer into something people already wear, such as a ring, a pair of glasses or clothing. The smaller the object, the tighter the compromises in battery, screen and sensors. Understanding those compromises is the best way to judge what a new gadget is likely to do well.
Smart rings
A smart ring packs a battery, a Bluetooth radio, a small processor and sensors into a band worn on a finger. Typical sensors include an accelerometer for movement, optical sensors for pulse and often a temperature sensor.
What they are good at. The finger has plenty of blood flow near the surface, which suits optical pulse sensing, and a ring is light and unobtrusive in bed. That is why rings are most often marketed for sleep tracking and for tracking resting trends such as heart rate and skin temperature over time. People who dislike wearing a watch to sleep may find one more comfortable.
Limits. There is no real screen, so everything is read on a phone. The battery is tiny, so charging is frequent, commonly every few days to about a week depending on the model. Size matters: a ring has to fit the finger, so makers usually offer sizing kits. Fit can change with temperature and swelling, and a loose ring gives worse readings. Rings can also scratch, and the gripping motion of gym exercises may be uncomfortable. Some brands require a paid subscription to unlock all the analysis, so it is worth checking the ongoing cost. As with any device, the outputs are estimates, as explained in the guide to how sleep stages are guessed.
Some rings also support tap-to-pay using NFC, which is explained in the article on contactless payments.
Smart glasses
Smart glasses are the most varied category. At one end are glasses with built-in speakers and microphones, used like open-ear headphones for music, calls and a voice assistant. Others add a camera for photos and video. A third group has small displays that project text or images into the wearer’s view, sometimes called augmented reality, which overlays digital information on the real world.
What they are good at. Hands-free audio and calls, taking a photo from your point of view, and glanceable information such as navigation prompts or notifications are realistic uses. Because the idea is to avoid pulling out a phone, they suit short, quick tasks.
Limits. Weight, heat and battery are the persistent challenges. Fitting a display, cameras, processors and batteries into a frame that still looks and feels like ordinary glasses is hard, so many models skip the display or offer only a small one. Battery life is often measured in hours of active use, not days. Prescription lenses may need special arrangements. Image quality from tiny cameras is generally below that of a phone.
Privacy. A camera on someone’s face raises understandable concern among people nearby, who may not realize they are being recorded. Many products include an indicator light, and some venues or workplaces ban such devices. Wearers should be aware of local rules and common courtesy. Footage and voice commands may also be sent to company servers for processing, so the question of what happens to captured data is especially relevant.
Smart glasses are related to, but not the same as, headsets used for virtual reality, which block out the real world and are generally used at home rather than worn on the street.
Other forms
- Smart clothing. Shirts and straps with woven or attached sensors, aimed at measuring things like heart rate or movement during sport. Washing, fit and cost are the practical hurdles.
- Clip-on and pocket trackers. Small devices that attach to belts, shoes or bags. Some track steps, others help locate lost items. They work on the same principles as an activity tracker.
- Earbuds with sensors. Some earbuds include motion and optical sensors, taking advantage of the ear as a place to sense pulse. See the article on Bluetooth earbuds for the audio side.
- Smart patches. Adhesive devices that record signals such as heart rhythm for short periods. Those used for medical purposes are made and supervised differently from consumer products, and are typically prescribed or recommended by a clinician.
- Wearable cameras and pins. Clip-on gadgets that capture video or answer voice requests, typically prompting the same privacy and usefulness questions as glasses.
- Pet and child trackers. Location tags worn on collars or clothes. They raise their own questions about who can see location data.
Questions worth asking before buying
- What problem does it solve that my phone or watch does not? If the answer is vague, it may be a novelty.
- How long does it last on one charge, and how is it charged? Proprietary cases and cables are easy to misplace.
- Does it need a subscription or an account? Features can disappear if a service closes.
- What data does it collect, and can I delete it? Check settings before first use.
- Does it work with my phone’s operating system? Compatibility is not universal.
- Is it comfortable all day? Comfort decides whether a device is worn at all.
New categories often start with a handful of strong features and a longer list of promises. Looking at present-day abilities rather than future plans is a safer way to judge them. Some of today’s ideas may mature, others may fade, and the broader direction of emerging technology is hard to predict with confidence.