经过几天摆弄 BlueZ 5 这就是我所拥有的。使用 BlueZ 5.50和 Raspbian Stretch（Pi 零 W）：
使用--compat启动蓝牙：
附加到/etc/systemd/system/dbus-org.bluez.service中的ExecStart行
或者
在 rc.local 中：sudo bluetoothd --compat &
接下来的步骤由下面发布的代码处理，但为了澄清，需要将 hciconfig 设置为：
sudo hciconfig hci0 sspmode 0
注意 #1：使用“sspmode 1 ”从 Android 配对时，您会收到输入 PIN 的提示，但之后 Pi 会自动生成 6 位密码并且配对失败。
注意#2： hciconfig hci0不能使用auth设置或加密那些将实际注册代理 DisplayOnly（我们将在下一步创建代理）作为KeyboardDisplay（sudo btmon 进行验证）并且配对不会使用预定义的 PIN。不确定 DisplayOnly 是否有原因无法使用身份验证、加密（可能与他们设置安全模式 3 有关）。
之后我们将使用bluetoothctl：
pi@raspberrypi:~ $ bluetoothctl
Agent registered
[bluetooth]# agent off
Agent unregistered
[bluetooth]# agent DisplayOnly
Agent registered
[bluetooth]# default-agent
Default agent request successful
[bluetooth]# discoverable on
Changing discoverable on succeeded
[CHG] Controller 11:22:33:44:55:66 Discoverable: yes
[bluetooth]# pairable on
Changing pairable on succeeded
[CHG] Controller 11:22:33:44:55:66 Pairable: yes
// Initiate pairing on remote device //
[NEW] Device AA:BB:CC:DD:EE:FF Android_phone
// Enter any PIN on Device AA:BB:CC:DD:EE:FF
Request PIN code
// retype your PIN below (on Pi)
[agent] Enter PIN code: <your PIN>
[CHG] Device AA:BB:CC:DD:EE:FF Class: 0x005a020c
...
[CHG] Device AA:BB:CC:DD:EE:FF Paired: yes
[bluetooth]# quit
注意#3：使用 pexpect 注册代理（如果您尝试运行下面发布的代码，请注意）与 BlueZ 5.43（Stretch 中的默认版本）是命中注定的
以下是设置 sspmode 并处理与预生成 PIN 配对的 Python 2.7 代码：
#!/usr/bin/env python
# -*- coding: utf-8 -*-
from __future__ import print_function # import print from python3: end=""
import time
import re
import pexpect # sudo apt-get install python-pexpect
import subprocess
import random
# !!! make sure bluetoothd runs in --compat mode before executing this script !!!
def pair_with_pin(start_time, pin, time_limit=60): # int(time.time()), pin - \d{4}, time_limit - approximate pairing window time in seconds, it might take up to 2x (nested timeout conditions)
"exectutes pairing with entered PIN on bluetooth adapter side"
pairing_status = False
try:
subprocess.call(['sudo','hciconfig','hci0','sspmode', '0'])
# bluetoothctl
child = pexpect.spawn('bluetoothctl')
child.expect("#")
child.sendline('agent off') # might be unnecessary
child.expect("unregistered")
child.sendline('agent DisplayOnly')
child.expect("Agent registered")
child.sendline('pairable on')
child.expect("pairable on succeeded")
child.sendline('discoverable on')
child.expect("discoverable on succeeded")
child.sendline('default-agent')
print ('Please input PIN: ' + pin)
# waiting for Phone to send a pairing request...
child.expect('Enter PIN code:', timeout = time_limit ) # timeout <= PAIRING_TIME_LIMIT to keep some kind of logic
while int(time.time()) < start_time + time_limit: # allow multiple pairing attempts during pairing window
child.sendline(pin)
i = child.expect(['Paired: yes', 'Enter PIN code:'], timeout = time_limit)
if i == 0: # found 'Paired: yes' == successful pairing
trust_mac = 'trust ' + re.search(r'(?:[0-9a-fA-F]:?){12}.+$', child.before).group(0) # extract MAC from last line, one with 'Paired: Yes'
child.sendline(trust_mac) # optionally add device to trusted
child.expect('trust succeeded', timeout = 10)
pairing_status = True
break
#else: # i == 1
# print('wrong PIN, retrying if time will allow')
except pexpect.EOF:
print ('!!!!!!!! EOF')
except pexpect.TIMEOUT:
print ('!!!!!!!! TIMEOUT')
# hide Pi's bluetooth for security reasons
child.sendline('pairable off')
child.expect("pairable off succeeded")
child.sendline('discoverable off')
child.expect("discoverable off succeeded")
child.close()
return pairing_status
#main program body
PAIRING_TIME_LIMIT = 60
BT_PIN = random.randint(1000,10000) # generate random 4-digit PIN 1000..9999
status = pair_with_pin(int(time.time()), str(BT_PIN), PAIRING_TIME_LIMIT)
if status == True:
print('Pairing successful')
最后说明：成功配对后，可能可以打开加密，尝试：
hciconfig hci0 加密
或者
hcitool 编码 $BDADD