Interface
The main way to connect a wearable gadget with external devices. For smartwatches and fitness bands (see "Type"), this refers to a connection to a smartphone or tablet, while in the case of watch-phones, it usually refers to headsets.
— Bluetooth. Wireless technology for direct communication of various devices with each other. This is the most popular interface in smartwatches and bracelets: Bluetooth modules can be made very tiny, the communication range even in the earliest versions reaches 10 m, and different generations of Bluetooth are mutually compatible in terms of basic functionality. Specifically, the versions nowadays are as follows:
- v2.0. The earliest standard used in modern wearable gadgets. The possibilities of such a connection are more modest than those of more advanced versions, but they are often quite enough.
- v3.0. A standard that combines classic Bluetooth v 2.0 and a high-speed “add-on” for transferring large amounts of data.
- v4.0. Further, after 3.0, improvement of Bluetooth: in addition to the classic and high-speed format, this version added Bluetooth Low Energy technology. Support of this technology is especially useful in fitness trackers, which usually transmit small amounts of data, but constantly.
- v4.1. Modification of the 4.0 standard described above with improved protection against interference while working with LTE mobile communications.
...i> v4.2. Another improvement of the 4.0 standard, which introduced, in particular, improved data protection and increased connection speed.
- — v 5. The fifth generation of Bluetooth was released in 2016. The key innovation in version 5.0 was the expansion of capabilities related to the Internet of Things. Thus, in the Bluetooth Low Energy protocol, it became possible to double the data transfer rate (up to 2 Mbit/s) at the cost of reducing the range, and also quadruple the range at the cost of reducing the speed; In addition, a number of improvements have been introduced regarding simultaneous work with a large number of connected devices.
- — v 5.1. Update of the version described above v 5.0. In addition to general improvements in the quality and reliability of communication, this update introduced such an interesting feature as determining the direction from which the Bluetooth signal is coming. This makes it possible to determine the location of connected devices with centimeter accuracy.
- —v 5.2. The next, after 5.1, is the fifth generation Bluetooth update. The main innovations in this version are a number of security improvements, additional optimization of power consumption in LE mode and a new audio signal format for synchronizing parallel playback on multiple devices.
- —v 5.3. The Bluetooth v 5.3 wireless communication protocol was introduced at the dawn of 2022. Among the innovations in it, they accelerated the process of negotiating a communication channel between the controller and the device, implemented the function of quickly switching between the operating state in a low duty cycle and a high-speed mode, and improved the throughput and stability of the connection by reducing susceptibility to interference. When unexpected interference occurs in Low Energy mode, the procedure for selecting a communication channel to switch from now on has been accelerated. There are no fundamental innovations in protocol 5.3, but a number of qualitative improvements are evident in it.
Of course, to use all the capabilities of a particular version of Bluetooth, it must be supported not only by the gadget itself, but also by the smartphone/tablet to which it is connected.
Sports modes
The number of types of sports training supported by the smartwatch. The more of them, the wider the coverage of the potential audience is provided by a wearable gadget on the wrist.
The most common sports modes include running, walking, cycling, swimming, elliptical exercise, and so on. The quantity and quality of data for different sports depends on the technical level of equipment of a particular device. While some models only record heart rate and roughly calculate the number of calories burned, other smartwatches evaluate the effectiveness of a workout using a detailed list of data and even draw a conditional run track based on information from GPS satellites.
Size
The size of the display installed in the gadget; for round screens, respectively, the diameter is indicated.
A larger screen, on the one hand, is more convenient to use, on the other hand, it significantly affects the dimensions of the entire device, which is especially critical for wearable gadgets. Therefore, manufacturers choose the display size in accordance with the purpose and functionality of each specific model — so that there is enough space on the screen and the device itself is not too bulky.
It is also worth mentioning that screens with a similar size may have different aspect ratios. For example, traditional smartwatches are usually equipped with square or round panels, while in fitness trackers, screens are often made elongated in height.
Screen resolution
Screen size in dots (pixels) horizontally and vertically. In general, this is one of the indicators that determine the image quality: the higher the resolution, the clearer and smoother the picture on the screen (with the same size), the less noticeable are the individual dots. On the other hand, an increase in the number of pixels affects the cost of displays, their power consumption and requirements for a hardware platform (more powerful hardware is required, which itself will cost more). In addition, the specifics of using smartwatches is such that there is simply no need to install high-resolution screens in them. Therefore, modern wrist accessories use displays with a relatively low resolution: for example, 320x320 with a size of about 1.6" is considered quite sufficient even for premium watches.
PPI
The density of dots on the screen of the gadget, namely, the number of pixels that are on each inch of the panel vertically or horizontally.
The higher the PPI, the higher the detail of the screen, the clearer and smoother the image is. On the other hand, this indicator affects the price accordingly. Therefore, the higher the density of points, the more advanced, usually, this gadget is in terms of general capabilities. However, when choosing a screen, manufacturers take into account the general purpose and functionality of the device; so that even a small number of PPIs usually does not interfere with comfortable use.
Source of power
The type of battery that is installed in the watch/bracelet.
— Li-Ion (lithium-ion). Battery of the original format, made using Li-Ion technology. Such batteries combine compact dimensions with good capacity, they are unpretentious in use, durable and reliable, and among the significant drawbacks, one can only note some sensitivity to low temperatures. As a result, this technology is one of the most popular in modern portable electronics, including wearable accessories.
— Li-Pol (lithium polymer). An updated and improved version of Li-Ion technology (see above). With the same basic advantages, lithium-polymer cells have even greater capacity with the same small dimensions and weight, they hold voltage more stable as they are discharged and are more resistant to low temperatures. At the same time, these batteries are somewhat more expensive.
— Battery. Powered by a replaceable battery — usually a compact "tablet" of one type or another. Such batteries have a relatively low capacity and are usually made disposable, that is, they cannot be recharged. Therefore, such power is found mainly among two categories of devices: in fitness trackers without a display, as well as watches of a classic design with a minimum of smart features that do not require a lot of energy.
Operating time (normal mode)
The time that the gadget can work on one battery charge (or the supplied battery) in normal use.
Normal mode, as a rule, means working with a relatively low load. At this time, the display can display some data, and basic functions can also work (counting steps, periodically checking heart rate, etc.), but in any case, power consumption is low. Therefore, the operating time in normal mode can be quite impressive, up to
several weeks, or even months. However, when choosing, it doesn’t hurt to also pay attention to the stated time in active mode (see below) — especially if a long operating time is critical, or you plan to use the gadget intensively. The actual autonomy of the device will most likely be somewhere in between these two values, depending on the actual load. If only the time in normal mode is indicated for the gadget, you should choose with a certain reserve.
Operating time (active mode)
The time that the gadget is able to work on one charge of the battery in the active mode of use.
For watch-phones (see “Type”), this usually means a talk mode, for other gadgets, an intensive work mode when numerous features and sensors are used and there is a constant exchange of data with a smartphone/tablet. However, the specific understanding of the "active mode" for different manufacturers may vary: some indicate the time at maximum performance (that is, in fact, guaranteed battery life), others — in some kind of "average mode". However, anyway, this is a fairly clear parameter that describes the battery life of a particular model quite well (and is much closer to real indicators than the time in normal mode mentioned above).
Note that for models with a GPS sensor (see "Navigation"), the specifications may additionally specify the time of active operation using such a sensor. See "Operating time (GPS)" for details.
Charging time
The time it takes to fully charge the battery of a wearable gadget is from 0 to 100%. In practice, this parameter depends on several factors: battery capacity (the larger it is, the longer the charging process will take), the power of the charger and charging technology (support for accelerated charging with increased power speeds up the process of restoring energy reserves in the battery cells). For most modern smart watches and fitness bracelets, full charging time varies from half an hour to a couple of hours. However, the specific time directly depends on the model of the gadget and the characteristics of the charger - it is advisable to clarify these points separately.