首先先了解一下bluez，以及常用的tools.
- hcitool、bluetoothctl等工具，可以进行BLE设备的扫描、连接、配对、广播等操作；
- hcitool可以发送HCI command，设置BLE的广播数据；
- gatttool可以在GATT层面，完成GATT profile的连接、service attribute的读写等操作；

bluez

安装
sudo apt-get install bluez

hciconfig

查看蓝牙设备

pi@raspberrypi:~ $ hciconfig
hci0:   Type: Primary  Bus: UART
    BD Address: B8:27:EB:26:23:F1  ACL MTU: 1021:8  SCO MTU: 64:1
    UP RUNNING 
    RX bytes:822 acl:0 sco:0 events:57 errors:0
    TX bytes:4231 acl:0 sco:0 commands:57 errors:0

所有命令如下

pi@raspberrypi:~ $ hciconfig --help
hciconfig - HCI device configuration utility
Usage:
    hciconfig
    hciconfig [-a] hciX [command ...]
Commands:
    up                  Open and initialize HCI device
    down                Close HCI device
    reset               Reset HCI device
    rstat               Reset statistic counters
    auth                Enable Authentication
    noauth              Disable Authentication
    encrypt             Enable Encryption
    noencrypt           Disable Encryption
    piscan              Enable Page and Inquiry scan
    noscan              Disable scan
    iscan               Enable Inquiry scan
    pscan               Enable Page scan
    ptype      [type]   Get/Set default packet type
    lm         [mode]   Get/Set default link mode
    lp         [policy] Get/Set default link policy
    name       [name]   Get/Set local name
    class      [class]  Get/Set class of device
    voice      [voice]  Get/Set voice setting
    iac        [iac]    Get/Set inquiry access code
    inqtpl     [level]  Get/Set inquiry transmit power level
    inqmode    [mode]   Get/Set inquiry mode
    inqdata    [data]   Get/Set inquiry data
    inqtype    [type]   Get/Set inquiry scan type
    inqparms   [win:int]    Get/Set inquiry scan window and interval
    pageparms  [win:int]    Get/Set page scan window and interval
    pageto     [to]     Get/Set page timeout
    afhmode    [mode]   Get/Set AFH mode
    sspmode    [mode]   Get/Set Simple Pairing Mode
    aclmtu     <mtu:pkt>    Set ACL MTU and number of packets
    scomtu     <mtu:pkt>    Set SCO MTU and number of packets
    delkey     <bdaddr> Delete link key from the device
    oobdata             Get local OOB data
    commands            Display supported commands
    features            Display device features
    version             Display version information
    revision            Display revision information
    block      <bdaddr> Add a device to the blacklist
    unblock    <bdaddr> Remove a device from the blacklist
    lerandaddr <bdaddr> Set LE Random Address
    leadv      [type]   Enable LE advertising
            0 - Connectable undirected advertising (default)
            3 - Non connectable undirected advertising
    noleadv             Disable LE advertising
    lestates            Display the supported LE states

hcitool

pi@raspberrypi:~ $ hcitool --help
hcitool - HCI Tool ver 5.43
Usage:
    hcitool [options] <command> [command parameters]
Options:
    --help  Display help
    -i dev  HCI device
Commands:
    dev     Display local devices
    inq     Inquire remote devices
    scan    Scan for remote devices
    name    Get name from remote device
    info    Get information from remote device
    spinq   Start periodic inquiry
    epinq   Exit periodic inquiry
    cmd     Submit arbitrary HCI commands
    con     Display active connections
    cc      Create connection to remote device
    dc      Disconnect from remote device
    sr      Switch master/slave role
    cpt     Change connection packet type
    rssi    Display connection RSSI
    lq      Display link quality
    tpl     Display transmit power level
    afh     Display AFH channel map
    lp      Set/display link policy settings
    lst     Set/display link supervision timeout
    auth    Request authentication
    enc     Set connection encryption
    key     Change connection link key
    clkoff  Read clock offset
    clock   Read local or remote clock
    lescan  Start LE scan
    leinfo  Get LE remote information
    lewladd Add device to LE White List
    lewlrm  Remove device from LE White List
    lewlsz  Read size of LE White List
    lewlclr Clear LE White List
    lerladd Add device to LE Resolving List
    lerlrm  Remove device from LE Resolving List
    lerlclr Clear LE Resolving List
    lerlsz  Read size of LE Resolving List
    lerlon  Enable LE Address Resolution
    lerloff Disable LE Address Resolution
    lecc    Create a LE Connection
    ledc    Disconnect a LE Connection
    lecup   LE Connection Update

For more information on the usage of each command use:
    hcitool <command> --help

bluetoothctl

打开bluetoochctl工具： bluetoothctl

pi@raspberrypi:/etc/systemd/system $ bluetoothctl
[NEW] Controller B8:27:EB:26:23:F1 raspberrypi [default]

扫描： scan on

[bluetooth]# scan on
Discovery started
[CHG] Controller B8:27:EB:26:23:F1 Discovering: yes
[NEW] Device 00:26:5E:DD:78:E6 00-26-5E-DD-78-E6

列出扫描到的设备：devices

[bluetooth]# devices
Device 00:26:5E:DD:78:E6 00-26-5E-DD-78-E6

退出：exit

[bluetooth]# exit
[DEL] Controller B8:27:EB:26:23:F1 raspberrypi [default]
pi@raspberrypi:/etc/systemd/system $

所有的命令如下：

[bluetooth]# help
Available commands:
  list                       List available controllers
  show [ctrl]                Controller information
  select <ctrl>              Select default controller
  devices                    List available devices
  paired-devices             List paired devices
  power <on/off>             Set controller power
  pairable <on/off>          Set controller pairable mode
  discoverable <on/off>      Set controller discoverable mode
  agent <on/off/capability>  Enable/disable agent with given capability
  default-agent              Set agent as the default one
  advertise <on/off/type>    Enable/disable advertising with given type
  set-advertise-uuids [uuid1 uuid2 ...] Set advertise uuids
  set-advertise-service [uuid][data=[xx xx ...] Set advertise service data
  set-advertise-manufacturer [id][data=[xx xx ...] Set advertise manufacturer data
  set-advertise-tx-power <on/off> Enable/disable TX power to be advertised
  set-scan-filter-uuids [uuid1 uuid2 ...] Set scan filter uuids
  set-scan-filter-rssi [rssi] Set scan filter rssi, and clears pathloss
  set-scan-filter-pathloss [pathloss] Set scan filter pathloss, and clears rssi
  set-scan-filter-transport [transport] Set scan filter transport
  set-scan-filter-clear      Clears discovery filter.
  scan <on/off>              Scan for devices
  info [dev]                 Device information
  pair [dev]                 Pair with device
  trust [dev]                Trust device
  untrust [dev]              Untrust device
  block [dev]                Block device
  unblock [dev]              Unblock device
  remove <dev>               Remove device
  connect <dev>              Connect device
  disconnect [dev]           Disconnect device
  list-attributes [dev]      List attributes
  set-alias <alias>          Set device alias
  select-attribute <attribute> Select attribute
  attribute-info [attribute] Select attribute
  read                       Read attribute value
  write <data=[xx xx ...]>   Write attribute value
  notify <on/off>            Notify attribute value
  register-profile <UUID ...> Register profile to connect
  unregister-profile         Unregister profile
  version                    Display version
  quit                       Quit program

RaspberryPi 发送beacon

苹果在BLE的基础上推出了iBeacon协议。iBeacon使用了BLE的广播部分，但不建立连接。一个遵守iBeacon协议的外设称为Beacon。Beacon会广播自己的身份信息和发射信号的强度。中心设备接收到广播之后，除了可以获知Beacon的身份之外，还能通过信号的衰减算出自己与Beacon的距离。

pi@raspberrypi:~ $ sudo hciconfig hci0 noscan 
pi@raspberrypi:~ $ sudo hciconfig hci0 leadv 3
pi@raspberrypi:~ $ sudo hcitool -i hci0 cmd 0x08 0x0008 1E 02 01 1A 1A FF 4C 00 02 15 63 6F 3F 8F 64 91 4B EE 95 F7 D8 CC 64 A8 63 B5 00 01 00 02 C5
< HCI Command: ogf 0x08, ocf 0x0008, plen 31
  1E 02 01 1A 1A FF 4C 00 02 15 63 6F 3F 8F 64 91 4B EE 95 F7 
  D8 CC 64 A8 63 B5 00 01 00 02 C5 
> HCI Event: 0x0e plen 4
  01 08 20 00