Comparison Xiaomi Redmi Band 2 vs Xiaomi Redmi Smart Band Pro

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 communication...s.
• v4.2. Another improvement of the 4.0 standard, which introduced, in particular, improved data protection and increased connection speed.
• v5.0. The fifth generation of Bluetooth, released in 2016. One of the most interesting improvements is the introduction of two special modes of operation for Bluetooth Low Energy: extended range (by reducing speed) and increased speed (by reducing range).

— USB. Wired connection to a computer/laptop using a USB cable. A rather specific option, found in some fitness trackers and children's beacons. During working hours, such a gadget functions completely independently, and the USB connection is used only occasionally, for some special tasks: transferring collected data to a computer, charging the battery, changing some settings, etc. This is not as convenient as a permanent connection via Bluetooth, therefore, in wearable gadgets, USB is rarely used as the main connection method.

— 3.5 mm (mini-Jack). Another wired connection method, almost completely similar to the USB described above and differing only in the type of connector. Also, the 3.5 mm plug is designed mainly to work with smartphones and tablets, and not with computers. However, it is also extremely rare.

— TFT. The simplest type of liquid crystal panel used in colour displays. They provide a relatively low, but generally sufficient image quality, while they are much cheaper than more advanced options. This type does not require backlight — more precisely, the backlight is part of the screen itself and turns on with it. Of the unequivocal disadvantages, it is worth noting that many TFT panels have rather limited viewing angles; however, as technology improves, this drawback is gradually eliminated.

— IPS. A variety of LCD panels created in an attempt to eliminate the shortcomings of TFT. There are many subspecies of IPS panels, but they all feature high colour reproduction quality, excellent brightness and wide viewing angles. The disadvantage of this option is the relatively high cost.

— OLED. In this case, we mean the technology used to create the simplest monochrome displays. In such screens, each segment that makes up the image is a separate LED, which eliminates the need for external illumination (and even the display itself can be used as a flashlight).

— AMOLED. Screens based on a panel of active organic light emitting diodes. Similar to various types of TFT, this technology allows the creation of high-resolution colour displays. Its key feature is that...the screen does not require a separate backlight system — in AMOLED panels, each pixel glows independently, resulting in somewhat lower power consumption. At the same time, such screens are distinguished by good colour reproduction quality, excellent brightness and wide viewing angles, however, they are much more expensive than TFT.

— Super AMOLED. An enhanced version of the AMOLED technology described above, delivering more expansive colour reproduction and brightness, as well as improved touch accuracy and speed, all at a thinner display and lower power consumption. In addition, the degree of reflection of external light is reduced, such a panel gives less glare and is better visible in sunlight.

— E-Ink (E-Paper). Displays made using "electronic paper" technology; in addition, this category also includes screens such as Memory LCD. The classic E-Ink screen is black and white, does not have a backlight (however, it can be built into particular gadgets), has a very low refresh rate and is poorly suited even for stopwatches, not to mention videos or animated pictures. On the other hand, "electronic paper" is perfectly visible in bright light and has a very low power consumption: it requires electricity only when the image is changed, while a still image remains visible even when the power is completely turned off. Memory LCD screens, in turn, with the same advantages, are almost as good as classic LCD panels in terms of refresh rate, but for a number of reasons they are not widely used.

— Transflective. A specific type of LCD panels that can work both due to its own backlight and due to reflected light. In bright external light (for example, in the sun), such a screen effectively reflects it and does not require a separate backlight — however, it is still included in the design and turns on in low light. This type of operation can significantly reduce power consumption compared to traditional LCD screens, where the image is not visible without backlight; in addition, good visibility in bright light is also an important advantage. The main disadvantage of panels of this type is their high cost; in addition, they are made mostly monochrome.

- LTPO. OLED and AMOLED matrices with an adaptive refresh rate that varies over a wide range based on the tasks performed. When rendering dynamic frames, screens with LTPO technology automatically raise the refresh rate to the maximum values, while viewing static images, they automatically reduce it to the minimum. At the heart of the technology is a traditional LTPS substrate with a thin TFT oxide film on top of the TFT base. Dynamic control of the refresh rate is provided by controlling the electron flow. The key benefit of LTPO screens is their reduced power consumption.

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 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.

The material from which the transparent cover of the display is made.

— Plastic. Inexpensive, moreover, quite durable and impact-resistant material: even with a strong impact, the plastic is more likely to crack than crumble into fragments. At the same time, scratches easily appear on such a surface, and over time it inevitably becomes cloudy. Because of this, plastic is found predominantly in inexpensive wearable gadgets.

— Glass. In this case, it can mean both classic silicate glass (the same as, for example, in windows), and some original types of impact-resistant glass that are not related to Gorilla Glass(see below). Regular glass costs more than plastic, but not by much, and it looks better and stays clear longer due to its scratch resistance. The main disadvantages of this material are fragility and a tendency to crumble into sharp fragments upon impact. Impact-resistant glass types are devoid of this drawback to one degree or another, but they are also more expensive. According to the price category of the gadget, you can quite accurately determine what kind of glass it uses — ordinary or shock-resistant.

— Sapphire. The coating made of synthetic sapphire is used exclusively in premium-class gadgets — this is due to the complexity of its production and, accordingly, the high cost. On the...practical side, sapphire is extremely scratch resistant (it is only possible to scratch such glass with a diamond or special tools), but at the same time it is fragile and easily breaks from impact.

— Gorilla glass. A family of shock-resistant glass types created by Corning and widely used in modern electronics, including wearable gadgets. In addition to strength, Gorilla Glass is also distinguished by good scratch resistance, while being relatively inexpensive (by the standards of such a coating), which has led to their popularity. However, the specific properties of such glass depend on its version; Here are the options that are relevant for modern wearable devices:

• Gorilla Glass v3. The oldest current version was released in 2013. Nevertheless, even such a coating is noticeably superior to traditional glass (not to mention plastic) in terms of transparency and scratch resistance.
• Gorilla Glass v4. Version released in 2014. A key feature was that the development of this coating focused on impact resistance (whereas previous generations focused mainly on scratch resistance). As a result, the glass turned out to be twice as strong as in version 3, despite the fact that its thickness was only 0.4 mm.
• Gorilla Glass SR+. The first version of Gorilla Glass, designed specifically for smartwatches and other miniature wearable gadgets; presented in 2016. According to the creators, the scratch resistance of such coatings approaches those of sapphire glass while maintaining the main advantages of Gorilla Glass — high strength and transparency. In general, for this material, superiority over "alternative options" is claimed by 70% in terms of strength specs and by 25% in terms of optical properties.
• Gorilla Glass DX. Another type of glass, specially designed for wearable devices. It was released in 2018 at the same time as the DX+ version (see below). Of the key improvements in Gorilla Glass DX, in particular, increased anti-reflective properties and an increase in the contrast level of the visible image by 50% are announced; the latter, among other things, allows you to reduce the actual brightness and, accordingly, the power consumption of screens without compromising image quality, which is especially important for miniature wearable devices. And this material differs from the DX+ type coating, on the one hand, by lower scratch resistance, and, on the other hand, by higher anti-reflective specs.
• Gorilla Glass DX+. Almost the same as the original version of DX, related to the same specialization — wearable wearable gadgets and other miniature devices. At the same time, DX + has a higher scratch resistance, but has slightly worse anti-reflective specs. Otherwise, these types of coverage are almost identical.

Bezel-less are displays in which the case or bezel does not occupy the usable area of the front panel, or it is minimized. In terms of design, bezels have both pros and cons. One of the most important reasons for adding substantial bezels to your screen is physical protection. The bezel-less display is very easy to scratch or damage when dropped. On the other hand, the frame takes up space on the screen, and this is one of the reasons why the frames in modern smartwatches are minimized, making the gadget more compact and stylish.

The model name of the processor (CPU) installed in the watch. Knowing this name, you can find detailed data on a particular CPU and evaluate its level and general capabilities. This is especially important due of the fact that these capabilities depend not only on the basic specs (number of cores, clock frequency), but also on specific design nuances.

— 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 oth...er electronics, 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 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.