As a young man in fashion and technology, there are several products that enhance personal temperament in life:Bluetooth headset, Bluetooth mouse, Bluetooth slightly, smart bracelet... Buy any one, even if you haven't even started using it yet, and you will feel that your life is improving rapidly, and your technological attributes will explode instantly.

Bluetooth tampons produced by a foreign company, just say geeks are not geeks| my.Flow

The word Bluetooth is all too familiar to us. But if you talk about and use Bluetooth all day long, what is Bluetooth?

It starts with a Danish king.

蓝牙，实际上是一种short-range wireless communication technology，是实现语音和数据无线传输的全球开放标准。不过蓝牙为什么这么“ 蓝 ” ？这就得追溯到公元 10 世纪丹麦的国王哈洛德·布美塔特（Harald Blåtand）头上了。哈洛德国王在约公元 958到986 年统治丹麦，他能征善战，终结了海盗时代，也统一了今天的挪威、瑞典和丹麦广大北欧地区。

King Harold Boumetat| wikipedia

丹麦语的Blåtand翻译成英语就是 Bluetooth，因此这位国王又叫Harald Bluetooth King（Harald Bluetooth）。关于这个名字的来历有诸多版本，一种传说是因为这位国王很喜欢吃蓝莓，导致牙齿都被染蓝了；也有史学家推测，是国王的某颗牙齿坏死了，在外观上看起来是蓝色的。

1996年，爱立信、诺基亚、东芝、IBM和英特尔公司计划成立一个行业协会，共同开发一种短距离无线连接技术。开发小组希望这项无线通信技术能像蓝牙王一样， Coordinate and unify work in different industrial fields。因此，这项技术就命名为Bluetooth。而蓝牙的标志正是古代北欧文字 ᚼ和 ᛒ的组合，也就是蓝牙王Harald Blåtand的首字母HB的合写。借助这个神奇的标志，这位丹麦国王的故事算是真的流芳百世了。

The meaning of the Bluetooth logo

Why should I use Bluetooth when I have Wi-Fi?

Both are short-distance communication technologies, and Bluetooth will inevitably be compared with Wi-Fi technology. So what is the difference between the two?

Bluetooth and Wi-Fi are inevitably compared

首先，从使用方式上，我们往往都是多个设备连接同一个Wi-Fi访问互联网，这是A one-to-many connection ，而蓝牙则是两台设备之间相互进行数据传输，是一种Point-to-point connection。从这方面看起来，蓝牙的Data security is higher。

Secondly, because Bluetooth uses a microstrip antenna, which is small in size and easy to integrate into the device, and the cost of the Bluetooth module is very low, the penetration rate of Bluetooth devices is very high; however, Wi-Fi devices require a separate network card and require routing. Equipment, high cost and relatively large power consumption.

在有些场景下，蓝牙比Wi-Fi更合适使用。举个例子，上海的朋友们在乘坐地铁时会经常使用一款软件，叫做“Metro Metro”。

Fig.| Shanghai Local Treasure

为了Protect the safety of passengers 'property and prevent QR codes from being swiped ，这款软件要求用户在使用时开启蓝牙，以便闸机和手机相互验证，验证通过才会开启闸机。假设这个软件使用网络或Wi- Fi进行认证，如果乘客的手机当时网络状况不佳，就会影响乘客进出闸机。而在这种情况下，使用蓝牙进行安全认证就是更合适的方案。

Does Bluetooth consume power?

But if you turn on Bluetooth to take the subway, will it consume the power of your mobile phone like crazy? To understand this problem, you also need to understand new developments in Bluetooth technology.

目前我们使用的蓝牙共有两种类型，Traditional Bluetooth and BLE（Bluetooth Low Energy）。传统蓝牙使用点对点的通信方式，这种通信方式是一种 Stay connected continuously的方案，一般用于数据量比较大的场景，如蓝牙耳机、音响等音频设备用的就是这种连接方式。

Listening to music with Bluetooth headphones relies on traditional Bluetooth connection| Oriental IC

BLE是低功耗蓝牙技术。与传统蓝牙相比，BLE最大的优点是Very fast search and connection speeds and low power consumption 。BLE完成一次连接（扫描设备、建立连接、发送数据等）只需要大约3ms ，任务完成后就会迅速切换到“非连接”状态，最大程度上降低了功率消耗。但是BLE物理带宽只有1M，数据传输速率低，所以BLE一般用于实时性要求高、但数据包非常小的设备，如键盘、遥控器等。

Bluetooth Low Energy technology is generally used in devices such as Bluetooth keyboards| Oriental IC

Take "Metro Metropolis" as an example. This software uses BLE technology. When passengers pass through the gate, the software can quickly establish a connection with the gate and complete the authentication through BLE. This process is almost imperceptible to the passengers and will not increase the waiting time for passengers to enter and exit the gate. Moreover, due to the use of BLE technology, Metro only needs to send a small data packet to the gate. After the authentication is completed, Bluetooth quickly enters the "disconnected" state, which greatly reduces power loss, and the power consumed is negligible for the mobile phone.

It passed with a whoosh| Oriental IC

Whether it's commuting to work, listening to music on the subway, or working wirelessly, the use of Bluetooth technology has made our lives more convenient. The next time you turn on Bluetooth, don't forget to thank the engineering romance from northern Europe and the Danish king from the distant Viking era.

It is no easy feat implementing digitalization initiatives in industries with many small and medium enterprises (SMEs) like agriculture.

[1]https://gizmodo.com/bluetooth-is-named-after-a-medieval-king-who-may- have-h-1671450657

[2]https://en.wikipedia.org/wiki/Harald_Bluetooth

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edit:Da Lin smashed

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