Comparison Amazfit T-Rex 2 vs Amazfit GTR 4

Types of notifications, as well as basic voice communication features supported by the gadget.

— Call notifications. Notifications about calls coming to the smartphone connected to the gadget, and for watch-phones — about calls to the watch itself. In classic smartwatches and fitness trackers (see "Type"), the specific functionality of such notifications can be different — from the usual sound or vibration signal to the ability to see the caller's number on the screen and accept/reject the call. But anyway, such notifications are often more noticeable to the user than the own signal of a smartphone deep in a pocket or bag.

— SMS notifications. Notifications about SMS messages received either on a smartphone connected to the gadget, or on the gadget itself, if it is capable of receiving messages (all watch phones and many children's beacons have this capability, see "Type"). The specific features of notifications can be different — from the icon "you have received a message" to the ability to read SMS and reply to it. Anyway, this feature often provides additional convenience — at least it reduces the likelihood of missing an important notification, and often also eliminates the need to once again take the phone out of your pocket / bag.

— Voice control. The ability to control the device through voice commands. In order for a smartwatch or f...itness tracker to perform some simple feature, it is enough to say its name aloud.

— Voice assistant. In watches with voice assistant support, the level of user interaction with the device is displayed in a new qualitative way. The most popular virtual assistants are Google Assistant and Amazon Alexa. In Apple devices, the role of an assistant is performed by Apple Siri, in Samsung wearable gadgets — a virtual assistant Bixby. Unlike the voice control function, the assistant does not just turn on this or that feature, but allows you to perform certain operations in applications that require feedback.

— Sound signal. The ability to give sound signals using the built-in speaker. This feature will be useful primarily in situations where the gadget is not on hand — for example, if it is used as an alarm clock and is removed at night.

— Vibration. Vibration signal similar to that used in mobile phones. In wearable gadgets, such a signal is especially convenient due to the fact that the device is constantly in contact with the wearer's skin, so that the vibration is perfectly felt — and regardless of the level of noise around. In addition, vibration mode is also useful in quiet environments where a loud sound signal is undesirable.

— Built-in microphone. Own microphone built into the body of the device. Such equipment can be used for different purposes, depending on the type and features of the gadget. First of all, voice communication is impossible without a microphone. Another feature for which a microphone is required is the voice assistant (see above). And in children's smartwatches, it may be possible to remotely turn on the microphone from the parent gadget and listen to what is happening around the child; see the relevant paragraph below for details.

— Speakerphone(speaker). The ability to work the gadget in hands-free mode, using the built-in speaker and microphone for conversation. In a conventional smartwatch (see "Type"), this feature allows you to talk through the watch without removing the smartphone from your pocket; in watch-phones, speakerphone allows you to do so without headphones and headsets, and for children's smartwatches, this feature is almost mandatory. However the volume of the built-in speaker is usually low, so in a noisy environment its power may not be enough.

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.

This block contains both various navigation systems ( GPS, Galileo) and auxiliary features for them ( aGPS, GPS tracking, maps, compass, altimeter , barometer). More about them:

— GPS module. GPS satellite navigation module built right into the watch/tracker. The initial purpose of such a module is to determine the current geographic coordinates; but how this information will be used depends on the specific type and model of the gadget. For example, in some devices GPS is used only for measuring the distance traveled and/or speed of movement, while more advanced models support full navigation and are equipped with built-in maps. In addition, this feature is almost mandatory in children's beacons (see "Type") — it is GPS that is responsible for determining the location of the child.

— aGPS. An auxiliary feature that allows you to speed up the start of the main GPS receiver. To work for its main purpose, such a receiver must update data on the location of navigation satellites; Obtaining this data in the classical way, directly from the satellites themselves, can take quite a long time (up to several minutes). This is especially true for the so-called "cold start" — when the receiver starts up after a long break in opera...tion, and the data stored in it has become completely outdated. aGPS (Assisted GPS) allows you to receive up-to-date service information from a mobile operator — from the nearest base station (this feature is supported by most operators nowadays). This can greatly speed up the startup process.

— GLONASS. This system is a Russian alternative to the American GPS. However it provides somewhat less accuracy, so GLONASS support is usually provided in addition to the GPS module. Simultaneous use of two systems, in turn, improves positioning accuracy.

— Galileo. European satellite navigation system, created as an alternative to the American GPS. Note that it is under the control of civilian departments, not the military. With a full fleet of 24 active satellites, the system gives an accuracy of up to 1 m in public mode and up to 20 cm with the GHA service. Working in conjunction with GPS, the Galileo system provides a more accurate position measurement, especially in densely populated areas.

— Maps. The feature of displaying topographic maps of the area with heights, relief and types of vegetation on the clock screen. Preinstalled maps are used for visual GPS navigation without being tied to a smartphone. Often, the ability to display maps is implemented in tactical smartwatches with a focus on tourism.

— GPS tracking. Many watches with the possibility of laying routes have the feature of guiding by the GPS track. At the same time, the wearable gadget acts as a navigator around the area, showing the route on the screen and suggesting where it is necessary to turn in one direction or another. Some smartwatches with a pronounced touristic bias also have a “Return Route” programme that allows you to go back along an already traveled route. In GPS tracker mode, trackpoints are usually recorded automatically based on the selected fixing interval. You can also mark a track point manually at any time.

— Compass. A classic compass is a device that indicates the direction to the cardinal points. Wearable gadgets usually use an electronic compass — a miniature magnetic sensor, the data from which, if necessary, are displayed on the display.

— Altimeter. A feature that allows you to determine the current altitude of the user's location. Note that the principle and format of the altimeter may be different. So, some models use barometer data for height measurements, others use information from a GPS sensor; the height itself can be determined relative to sea level, relative to some reference point, or in any of these ways, at the choice of the user. These details should be clarified separately.

— Barometer. A feature that allows you to determine the current atmospheric pressure. One of the applications of the barometer is weather forecasting: for example, a sharp drop in pressure usually signals the approach of bad weather. In addition, information from this sensor can be used to operate the altimeter (see above); and even if the gadget does not have an altimeter, the height difference between two points on the ground can be easily calculated from the pressure difference between them.

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 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.

The amount of own storage provided in the design of the watch/bracelet. This memory is used for permanent storage of various information: call log, received SMS and other messages, additional applications, data on physical activity for a certain time, etc. The larger its volume, the more data can be stored in the device without the need to clean it to free up space. On the other hand, in the operation of smartwatches, large volumes ( 64 GB, 32 GB, 16 GB, even 8 GB and 4 GB) are not always required, capacious drives are quite expensive, and replaceable cards installed in corresponding slot (see below).

— Built-in player. The presence of a player in the smartwatch allows you to use the gadget to listen to music. There is no need to connect to the phone for this. The songs will play directly from the watch. Therefore, these devices must necessarily have an impressive (as for a watch) amount of storage and be able to connect to headphones (for connection with headphones).

— Light sensor. A sensor that monitors the brightness of ambient light. One of the most popular ways to use this feature is to auto-adjust the brightness of the display: in bright light, it increases so that the image remains visible, and at dusk it decreases, which reduces eye strain and energy consumption. In addition, other more specific features may be provided — for example, turning on the screen when pulling back the sleeve of clothing.

— WiFi. A technology originally used to access the Internet via wireless access points, but more recently also used for direct communication between two devices (such a connection has several advantages over traditional Bluetooth). In wearable gadgets, the first option is most often provided, although the second is also found. However, the specific uses of Wi-Fi may be different depending on the device: accessing websites and various Internet services, remote communication with smart home systems, remote control of digital cameras and other electr...onics, transmission of the GPS- coordinates via Internet (in children's beacons), etc.

— NFC. Wireless communication technology over short distances (up to 10 cm). The methods of its application, including in wearable devices, may be different. One of the more popular options is using contactless payment (see below); however, the presence of such a function does not hurt to verify separately. Another common feature is the simplification of Bluetooth connection with a smartphone or tablet that also has NFC: instead of manual configuration, it is enough to bring one device to another — and they will automatically establish a connection, all that remains is to confirm it. Other ways of interaction may also be possible, for example, launching a “sports” application on a smartphone when bringing a fitness tracker to it. And theoretically, more specific options for using NFC are also allowed — for example, as a travel pass, ID, etc. Actually, in many models of wearable gadgets, the set of these methods is limited only by installed applications.

— Contactless payment. The possibility of using a wearable gadget for contactless payment. This feature is found only in models with NFC (see above); it actually turns the device into an analogue of a credit card with a chip and allows you to pay without taking the card out of your wallet — just bring your hand with the gadget to the terminal reader. This provides not only additional convenience, but also security. So, bringing the watch to the terminal is definitely easier than reaching into your pocket or purse for a credit card — especially if your hands are busy shopping. And instead of a traditional card, from which an attacker can copy basic details such as a number, CVV code and expiration date (for example, by “peeping” them with the built-in camera), a gadget is used that transmits this data in encrypted form and does not display it explicitly anywhere.
To use contactless payment, usually, you need to synchronize your gadget with your smartphone and set up such payment in the Google Pay or Apple Pay system. But to make payments, a smartphone is no longer required — many wearable devices are able to perform this feature completely autonomously (although this possibility still needs to be specified separately).

— Accelerometer. A sensor that determines the direction of gravity, as well as the accelerations acting on the device. This allows you to track two parameters at once: the current position in space and various physical influences (like tapping or shaking). Most often, the accelerometer is responsible for two main features: automatic rotation of the image on the screen, as well as the operation of the pedometer (in fact, the presence of such a sensor is almost guaranteed to mean the presence of a pedometer, see "Possible measurements"). However, there are other ways to use this sensor — for example, rejecting an incoming call when shaking the watch, turning on the screen when tapping on it, etc.

— Gyroscope. A device that allows you to track the turns of the gadget in one direction or another. Typically used in conjunction with an accelerometer. The gyroscope improves the accuracy of positioning in space (which has a positive effect on the quality of the pedometer and other similar functions), and also provides additional options for managing gestures. However, the specific applications of this sensor are highly dependent on the model.

— Camera. The watch/bracelet has its own built-in camera; its location and purpose differs from model to model. In some devices, the lens is located on the front panel, above the screen, and the matter is limited only to video communication and taking selfies, while others allow you to shoot “classic” photos or videos. At the same time, it is worth noting that anyway, the specs of such cameras are usually very limited — for example, the resolution rarely exceeds 2 megapixels, and autofocus is provided only in the most advanced models.

— Flashlight. Built-in flashlight — usually in the form of a small LED mounted directly in the case. Usually, it has a relatively modest brightness, but it can still be useful for simple tasks like lighting your path at night, lighting in a garage or basement, etc.

The method of charging the battery provided in the gadget.

— MicroUSB. Charging via standard microUSB port. The main advantage of this option is the ability to charge from any microUSB cable or charger with such a connector, not necessarily branded. On the other hand, the connector itself is quite large by the standards of wrist devices and can significantly affect the increase in the dimensions of the gadget.

— USB type C. A compact version of the USB interface with a reversible design that allows the plug to be inserted in either direction. The USB type C specification provides for a number of advanced power options - in particular, various fast charging technologies have been developed for this connector.

- Branded connector. Charging via a cable that connects to the watch using the original proprietary interface. The other end of the cable, as a rule, has a standard interface - most often USB, which allows you to use any computer port or network adapter with such a connector for charging. Branded connectors can be smaller than microUSB, and fit better into the layout of the clock. However, for charging, as a rule, you have to use only original accessories, including branded cradles-stands, which are intended mainly for permanent stay in one place.

- Wireless. The main advantage of wireless c...harging technology is the absence of any connectors - which is important, given the miniature size of wrist gadgets. At the same time, this method takes more time and significantly affects the cost of the device. Note that wireless charging is not contactless: the corresponding chargers can take the form of a stand or platform on which you need to put the watch, or a magnet attached to the back cover of the gadget, etc.

- Magnetic. Charging via a cable with convex metal contacts that are magnetized to the connector on the back cover of the wearable gadget. The magnetic contact group has no gaps, which improves the dust and moisture protection qualities of the smartwatch, and the charging plug itself is attracted to the magnetic connector, eliminating the need to look for the correct position for connecting the cable.

- USB A connector. The presence of a built-in connector allows you to connect the gadget directly to the charger, laptop, power bank without using additional cables.

The capacity of the battery that is installed in the gadget.

Theoretically, the higher the capacity, the longer the battery can work on a single charge. However, in fact, the battery life of the gadget also depends on its power consumption, and it is determined by the specs of the display and the hardware. Therefore, only models of the same type with very similar specs can be compared in terms of battery capacity; and for an accurate assessment of battery life, it is better to focus on the directly claimed operating time in one mode or another (see below).

It is also worth mentioning that high-capacity batteries inevitably turn out to be quite heavy and bulky. So the capacity of batteries installed in wearable gadgets is also greatly limited by size and weight.