Comparison Xiaomi Smart Band 9 Active vs Xiaomi Mi Smart Band 8 Active

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.

— 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 doe...s 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.

The maximum brightness in nits that the screen of the device produces.

The high-brightness displays remain legible under intense ambient light, which is important for quickly retrieving information from the dial outdoors on a clear sunny day. However, a large margin for this parameter affects the cost and power consumption of the display, which reduces the battery life of a wearable device.

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 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.

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.

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.

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.

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.