Bluetooth module, is a kind of PCBA board with integrated Bluetooth function, used for short distance wireless communication. According to the function, it is divided into Bluetooth data module and Bluetooth voice module. Bluetooth module refers to the integrated bluetooth function of the chip basic circuit collection, used for wireless network communication, can be roughly divided into three types: data transmission module, bluetooth audio module, bluetooth audio+ data two-in-one module and so on. The general module has the property of semi-finished product, which is processed on the basis of the chip to make the subsequent application more simple.
This article is from the different classification of Bluetooth modules to sort out the type of Bluetooth module, as far as possible from the classification point of view to understand the Bluetooth module has some features and functions.
1.Categorized by protocol type
(1) Classic Bluetooth module
Classic Bluetooth module (BT) refers to Bluetooth protocol support 4.0 or less modules can be subdivided into: traditional Bluetooth module and high-speed Bluetooth module.
Traditional bluetooth module: bluetooth was born at the beginning, the use of BR basic rate technology, the bluetooth theoretical transmission rate, can only reach 721.2Kbps, launched in 2004 to support the bluetooth 2.0 protocol module, the outbreak of the smartphone era, the new EDR bluetooth enhancement rate (Enhanced Data Rate) technology, by improving the multitasking and a variety of bluetooth By improving multitasking and the ability of multiple Bluetooth devices to operate simultaneously, it enables Bluetooth devices to transmit at rates up to 3Mbps, which is three times the transmission rate of Bluetooth 1.2 technology. As a result, in addition to more stable audio streaming and lower power consumption, you can take full advantage of bandwidth to connect multiple Bluetooth devices at the same time.
High-speed Bluetooth module: High-speed Bluetooth module was launched in 2009, the main representative is to support the Bluetooth 3.0 protocol module, the new High Speed technology, you can make Bluetooth call 802.11 WiFi used to achieve high-speed data transmission, the transmission rate of up to 24Mbps, is the traditional Bluetooth module of 8 times.
Classic Bluetooth module is generally used for continuous streaming of audio and data volume is relatively large transmission, such as voice, music, wireless headphones, file transfer between devices, printers, wireless speakers and so on.
(2) Bluetooth Low Power Module
LowPower Module (BLE) means a module that supports the 2010 launch of Bluetooth Protocol 4.0 or higher . The biggest feature is the reduction in cost and power consumption . Bluetooth low-power technology uses variable connection time intervals. The interval can be set according to the specific application for a few milliseconds to a few seconds ranging from BLE technology using a very fast connection, so it can be in the “non-connection” state (energy saving), when the connection between the two ends of the link is only necessary to open the link, and then close the link in the shortest possible time. Then the link is closed in the shortest possible time.
Low-power Bluetooth is used in real time. Requirements are relatively high, but low speed, low power consumption of the scene, such as mouse and keyboard, heart rate detectors and thermometers and other sensor devices, smart home, smart wear such as the need for large amounts of data interaction in scenarios, is very suitable for Internet of Things applications.
To sum up, classic Bluetooth is not an outdated version of BLE. Classic Bluetooth and low-power Bluetooth coexist and are used in different applications, which completely depend on the different needs of each person.
2.Categorized by support for protocols
According to the number of Bluetooth protocol stack support can be divided into single-mode module and dual-mode module. The concept of single mode and dual mode is only available after the emergence of BLE Bluetooth. We should choose the required module according to cost, application and function.
(1) Single mode module
Single mode module is the module that supports a certain Bluetooth protocol, only the classic Bluetooth (BT) protocol or Bluetooth Low Power (BLE) protocol.
(2) Dual mode module
Dual-mode modules are modules that support both the classic Bluetooth (BT) protocol and the low-power Bluetooth (BLE) protocol, and can run two sets of protocol stacks. There are two types of dual-mode modules: Classic Bluetooth (data only)+ BLE and Classic Bluetooth (data+ audio)+ BLE. Dual-mode modules have good flexibility and compatibility.
Bluetooth dual mode is undoubtedly the mainstream of the future. Classic Bluetooth power consumption, 4.0 after Bluetooth BLE, power consumption is small, but does not support the audio protocol and due to data transmission speed limitations, Bluetooth dual mode is a combination of the advantages and disadvantages of the two, can support both audio transmission, can also support data transmission, low power consumption, and compatibility is the sum of the two.
3.Categorized by function
Standing in the Bluetooth module to transmit the size of of the functional point of view content, can be divided into the following categories.
(1) Data module
The general use of more data modules, i.e. Bluetooth low power, also known as Bluetooth transmission module. Because the amount of data is not large, the transmission of proximity, operation and standby power consumption has strict requirements for the device is a good choice. Due to the advantages of power consumption, Bluetooth 4.0 module has now occupied most of the share of mobile data transmission, and the size and share is expected to continue to grow.
(2) Audio Module
The audio module requires a very large bit of streaming data, so it is more suitable for the classic Bluetooth module.
(3) Composite data and audio modules
It can transmit voice, audio and data at the same time. Under the trend of mobile Internet, data+ audio application, the dual mode module with data and audio composite is a good choice.2\According to the protocol support points
4. According to the chip design classification
This is differentiated according to the type of storage used by the Bluetooth chip in the module.
(1) ROM version
In general, the chip manufacturer’s ROM version of the chip, characterised by the chip manufacturer, will be the standard application PROFILES cured in the chip. Usually a fixed function, the user can not modify the program in the chip. Can be connected to an external EEPROM, storage space is small, can be used to store Bluetooth address, device name, PIN code , etc.
Use the ROM version of the chip to do less differentiation of the product, but the development is simple. For some conventional products, they do not need deep customization of the product. The choice of ROM version of the chip can be developed to speed up the development progress, speed up the time to market. Suitable for large-scale mass production, the price is very low, more commonly used for dongles, Bluetooth headset modules, cell phone modules, mouse and keyboard modules, etc., can modify the configuration parameters, but the basic function is fixed. Large-scale civilian products generally use the ROM version of the module, such as USB Bluetooth adapters on the market, because most of the protocol will run inside the PC. The chip processing power requirements are very low, so the chip manufacturer will launch very low-priced products.
(2) FLASH version
Chips are generally built-in FLASH, storage space is large. If you want to do some customer-defined products, such as the need to add some sensors, communication with external MCU, increase Bluetooth protocol or service, you need to use the FLASH version of the chip in the FLASH version of the existing project to add their own engineering code, develop their own firmware, to make a differentiated product. Relatively speaking , it is more flexible.
FLASH version of the chip price is high, but the user can be carried out according to their own application needs, due to the chip built-in FLASH storage, the performance of its performance, while built-in audio codec circuitry, suitable for a variety of voice gateway and other applications. Industrial Bluetooth applications should generally use the FLASH version of the chip produced by the module, fast running, with high integration, high reliability, high performance indicators and other characteristics.
(3) EXT version
EXT module chip without FLASH memory, the need to expand the memory device, the user can carry out application development, characterized by moderate prices, shortcomings are stability, power consumption and other performance differences, while most EXT chip does not have audio decoding circuits, such as the need to realizeio transmission needs to be connected to an external codec device.
5. Classification according to power
In terms of power, there is a difference between low-power Bluetooth and classic Bluetooth.
Low power Bluetooth has no power level, the transmission distance can be more than 100m, 5.0 protocol distance even up to 300m, the specific distance depends on the product design power. The modulation of Bluetooth Low Power technology is slightly different from traditional Bluetooth technology. This different modulation uses a 10mwdb wireless chipset (Low Power Bluetooth’s maximum power) to achieve a connection range of up to 300m, which means that the entire range of homes and buildings can be covered, achieving a more robust and reliable connection.
Classic Bluetooth has three levels of power, expressed in Class. According to the Bluetooth specification, Class is not used to specify distance, but to indicate transmit power. Bluetooth module transmit power parameters are determined, the actual transmit efficiency and RF circuit, antenna efficiency related to the Bluetooth module communication distance and transmit power, reception sensitivity and application environment is closely related to Bluetooth work in the 2.4G band, penetration capacity is poor, in the case of blocking, should be in the actual field to test the communication effect. The purpose of power control is to control the radiation within the limits without interfering with the normal operation of neighboring Bluetooth devices, using the link management protocol to realize the power control algorithm between master and slave devices.
(1) Class 1
Class 1 output power of 1mW (0dBm) to 100mW (20dBm), support for 100m transmission distance, in order to achieve the maximum range, power control is mandatory. Class 1 is used in high-power, long-distance Bluetooth products, but because of the high cost and high power consumption, it is not suitable for cooperation with personal communication products (cell phones, Bluetooth headsets, Bluetooth Dongle, etc.), so it is mostly used in long-distance transmission.
Generally, few people will use long-distance transmission, but if you want to transmit audio over a long distance, connect audio over a long distance, and more commonly in some large-scale venues, stages, and industrial scenarios, using a Bluetooth adapter that supports Class 1 is the best solution.
(2) Class 2
Class 2 output power of 0.25mW (-6dBm) to 2.5mW (4dBm), power control is optional, under normal circumstances 1mW (0dBm) supports 10m transmission distance, as long as the transmitter power can exceed 0dBm is part of the scope of Class 2, but if more than 4dBm, then it is Class 1.
Most of the common Bluetooth devices on the market today are power consumption Class 2, mostly used in cell phones, Bluetooth headsets, Bluetooth Dongle personal communication products, power consumption and smaller size, while easy to carry.
(3) Class 3
Class 3 output power ≤ 1mW (0dBm), support 1m transmission distance. With the lowest output power, Class 3 devices are not common due to their very limited range of coverage.
6. Classification according to the support temperature
(1) Commercial grade
The temperature range is about 0℃~70℃. Generally used in ordinary consumer products, more common in life and lower prices are cheaper. Suitable for environmental conditions (such as temperature, EMC and mechanical stress) at a mild to moderate level in consumer product applications. Such as a variety of consumer electronics, smart home appliances, entertainment devices, mobile computing, cameras, monitors, routers and test equipment.
(2) Industrial Grade
The temperature range is about -40°C to 85°C. Generally used in industrial environments, but also able to operate outdoors where the environment is not so good or where there is interference. Compared to commercial grade products, industrial grade products can withstand more extreme environments, and are suitable, expected, or required to be used in types or qualities for industrial use, such as transportation, factory automation, and high shock and vibration environments.
(3) Automotive grade
The temperature range is approximately -40℃ to 125℃. Generally used in automobiles or harsh environments, due to the high heat generated during the start-up process of automobiles, it will be a bit higher in terms of high temperature and more expensive than industrial grade, which may be subject to high levels of EMI, collision, shock and vibration, and extreme temperatures. This type of product is therefore designed for automotive, transportation and other mission-critical applications and meets industry-standard automotive specifications.
(4) Military Grade
The temperature range is approximately -55℃ to 150℃. Generally used in military equipment, so the requirements are also the most stringent, mainly used in missiles, aircraft, tanks, aircraft carriers and other military fields. Grade is the most advanced, high precision, advanced technology and at the same time expensive, military grade is generally several years ahead of industrial grade time.