Comparison Amazfit Bip 3 vs Amazfit Bip U

Types of sports and medical data collected by the gadget (plus some features of a similar purpose, such as sleep tracking, smart alarms, stress levels and women's calendar). Note that the features from this list can be found not only in specialized fitness trackers (see "Type"), but also in more traditional devices like smartwatches. Here are the most popular options:

— Pulse rate. Heart rate is one of the most important physiological parameters of a person. So that sports training is as effective as possible, the heart rate must be in a certain range (the specific value depends on the purpose of the training and the personal data of the user). And for some illnesses and treatments, a faster or slower heart rate can be an important signal, including a warning of danger.

— Pressure (tonometer). A sensor that measures the user's blood pressure. Note that the accuracy of such a sensor is usually quite low, the measurement error can be 10% or even more; so it will not replace a full-fledged medical tonometer. On the other hand, a gadget with this feature is quite capable of detecting a critical increase or decrease in pressure, which will allow you to take the necessary measures in a timely manner.

— ECG. A sen...sor that allows you to get detailed data about the work of the user's heart. Note that such a sensor is not a full-fledged electrocardiograph — in fact, it is an advanced type of heart rate monitor that can track the features of the heart rhythm. However, even this is enough to detect some dangerous phenomena — for example, atrial fibrillation, which at first is imperceptible to a person — and take appropriate measures in time.

— The blood oxygen. A sensor (the so-called pulse oximeter) that determines the saturation of the blood with oxygen (saturation); at the same time, the measurement is carried out by a non-invasive method — without punctures and other damage to the skin. Like most medical sensors in wearable gadgets, it is not accurate and is not a full-fledged medical device, but it is quite capable of responding to a critical decrease in the level of oxygen in the blood. It is believed that the presence of a pulse oximeter is relevant primarily for certain diseases, when saturation may decrease due to the disease itself or the characteristics of the treatment being taken. However, this feature can also be useful for quite healthy users who often travel at high altitudes — primarily climbers and aeronauts.

— Body temperature. The presence of a sensor for measuring temperature allows you to take measurements without the use of thermometers. Naturally, errors can occur, so a slight deviation from the norm may not be determined, but the device will easily fix a significant increase in temperature.

— T° of the environment. Even though smartwatches are worn on the body, the built-in sensors in them are usually designed to measure the ambient temperature. This information can be useful both for a general assessment of the surrounding conditions, and for specific purposes — in particular, weather forecasting. It is not uncommon for watches with this feature to also have a barometer (see "Navigation").

— Number of steps. The traditional pedometer is a feature for counting the number of steps taken by the user. These measurements usually use data from the accelerometer, and the results are quite accurate: most modern accelerometers are well calibrated and are quite capable of distinguishing tremors during steps from hand waves and other extraneous movements. The exception is trips in land transport: many wearable gadgets perceive shaking as steps, which should be taken into account when evaluating the results.

— Distance travelled. Measurement of the total distance traveled by the user. For this, either data from a pedometer or a GPS module are usually used (see "Navigation"); each option has its own merits. So, the pedometer is cheaper, it can be used even in rooms without windows, where the signal from satellites does not reach, and on simulators like treadmills, where the user does not move relative to the ground. GPS, in turn, gives higher accuracy, especially over long distances, and is not prone to false positives in vehicles. In some advanced gadgets, these methods can be combined — this is not cheap, but it allows you to combine the advantages of both options and achieve maximum accuracy.

— Movement speed. Determining the speed of the user's movement. As with distance travelled, measurement can be done in a variety of ways; see above for more details. Also note here that many gadgets with this feature are able not only to determine the current speed, but also to constantly record its value and display various indicators: the maximum achieved speed, the average value for training, etc.

— Energy spent (calories). Measurement of the number of calories burned by the user in the process of movement. These data are rather approximate, as they are calculated by indirect parameters (speed and range of movement, personal specs of a person, etc.). However, even this accuracy is quite enough to determine the overall effectiveness of training.

— The amount of fat burned. Measuring the amount of fat burned per workout. As in the case of calories (see above), the result of such measurements is quite approximate. However, in fact, absolute accuracy is not required, and fat loss data can be a powerful motivator.

— Activity time. A measurement of the total time during which the user is actively moving. In many models, such metering may provide additional options, such as fixing several periods of activity with breaks between them and determining the ratio between the time of movement and the time of rest.

— Smart alarm. An alarm clock that monitors the user's sleep phases and gives a signal to wake up at the optimal time for this. Human sleep consists of alternating phases, and waking up in the unfortunate phase creates a feeling of lethargy and fatigue, even if there was enough time to sleep. A smart alarm clock avoids such situations; its work is based on tracking the pulse, breathing rate and other parameters that differ depending on the phase of sleep. Note that the deviation of the signal from the set time can be up to half an hour, but this is usually a deviation towards an earlier rise. As a result, the risk of being late with a smart alarm clock is close to zero, and the lack of sleep time is compensated by the optimal moment of awakening.

— Sleep tracking. Sleep quality assessment is based on data from on-board sensors of fitness trackers or smartwatches. In particular, the heart rate monitor controls the number of contractions of the heart muscle, the accelerometer controls the user's movements. A blood oxygen sensor, if available on the wearable, improves the accuracy of sleep quality data collection. According to the readings of the sensors, the moments of entering and exiting the deep sleep phase are recorded. It is during this period that the restoration of the nervous system and the accumulation of energy for the coming day take place. In deep sleep, a person can completely reboot and gain strength, while in REM sleep, brain activity practically does not differ from the state of wakefulness. The sleep quality analysis feature helps you determine the best time to go to sleep and provides personalized recommendations to improve your night's sleep.

— The level of stress. The level of stress of the body allows you to evaluate the metric that determines the variability of the heartbeat — the difference in time between successive contractions of the heart muscle. Respiration rate, maximum oxygen consumption and excess oxygen consumption after exercise are also taken into account. The stress level score gives a clear picture of the user's experience during the day, however, the value of this parameter is in determining the most optimal body regimen for training. A high heart rate variability usually indicates you are in good shape for playing sports, while a low one can indicate fatigue, dehydration, or feeling unwell. All this directly affects the ability to train effectively. There are no clear units for measuring the level of stress — in smartwatches, the parameter is usually shown as a scale from 0 to 100, often indicating the number of hours the body is under stress and the time it takes to recover to a normal state.

— Women's calendar. The tool for tracking the menstrual cycle keeps abreast of the events of the expected dates of the menstrual period, allows you to determine the most favorable days for conception, helps to notice alarming symptoms in time and prevent many diseases in case of cycle disorders. Based on your total cycle length, the device calculates a predicted date for your next period. The women's calendar records cycle dates, fertility windows, and the day of ovulation. By adding your own notes to it, you can track fluctuations in sleep, appetite, fitness, mood changes and predict well-being for a particular day.

In addition to those described above, more specific types of measurements can be found in modern wearable gadgets.

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.

— 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 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 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.

— 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.