我用RPi内置的模块和Arduino上的HC-05模块，在Raspberry Pi 3b+和Arduino Mega之间建立了蓝牙连接。双向通信的效果非常好，一次可以持续几分钟，有时甚至几个小时。
然后，在看似随机的时间里，python代码挂起，被阻塞在 sock.recv() 功能。我可以通过ctrl-c杀死它，然后重新启动它，它通常会顺利地重新连接。
我知道蓝牙是个小问题，所以如果有任何关于如何使通信更强大和延长运行时间直到挂起的建议，我肯定会感激不尽，但我更感兴趣的是如何检测这种 "挂起"，并从中恢复，即：我想直接杀死连接，然后在Python程序中尝试重新连接，而不是让我自己看到这种情况并做出反应。
这是我目前在python中的做法。
#!/usr/bin/python3
import datetime
import socket
import sys
import time
import bluetooth
COMMAND_START_CHAR = '<'
COMMAND_END_CHAR = '>'
LOGFILE = 'bt.log'
def SearchForFullCommand(buffer):
"""Puts fully formed commands from buffer into a list, returning the remaining buffer.
We expect commands to be demarcated by COMMAND_START_CHAR and COMMAND_END_CHAR. The
buffer may have zero or more such commands. This function finds all demarcated commands,
strips off those demarcations, and returns the remaining buffer. Any text that arrives
before a COMMAND_START_CHAR is discarded.
Args:
buffer: string representing the text received so far.
Returns:
A 2-tuple, where the first element is the remaining buffer, and the second element
is a potentially empty list of identified commands.
"""
commands = []
while COMMAND_END_CHAR in buffer:
end_pos = buffer.find(COMMAND_END_CHAR)
if COMMAND_START_CHAR in buffer[:end_pos]:
start_pos = buffer.find(COMMAND_START_CHAR) + len(COMMAND_START_CHAR)
commands.append(buffer[start_pos:end_pos])
buffer = buffer[end_pos+len(COMMAND_END_CHAR):]
return (buffer, commands) # no command found
def Log(s):
"""Appends message s to the logfile."""
with open(LOGFILE, 'a') as f:
f.write('%s\n' % s)
def ConnectBluetooth(address, port):
"""Attempts to make one connection to the given address and port."""
sock = bluetooth.BluetoothSocket(bluetooth.RFCOMM)
sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
try:
sock.connect((address, port))
except (bluetooth.btcommon.BluetoothError) as e:
Log('Failed to connect: %s' % e)
return None
return sock
def ConnectBluetoothRetry(address, port, seconds):
"""Attempts to make connections for a number of seconds, exiting program on fail."""
second = 0
while second < seconds:
sock = ConnectBluetooth(address, port)
if sock:
Log('Connected after %d seconds' % second)
return sock
time.sleep(1)
second += 1
Log('Failed to connect after %d seconds' % second)
sys.exit()
def main():
"""Sends sequential numbers over bluetooth, and receives & parses anything sent."""
sys.stderr = open(LOGFILE, 'a')
start = time.time()
timestring = datetime.datetime.fromtimestamp(start).strftime('%Y-%m-%d %H:%M:%S')
Log('Started at %s' % timestring)
bd_addr = '98:D3:11:FC:42:16'
port = 1
sock = ConnectBluetoothRetry(bd_addr, port, 10)
buffer = ''
x = 0
while True:
try:
recv = sock.recv(1024)
except (bluetooth.btcommon.BluetoothError) as e:
Log('Failed to receive: %s' % e)
sock.close()
sock = ConnectBluetoothRetry(bd_addr, port, 10)
Log('.. %s (len=%d) after running for %.3f hours' % (
recv, len(recv), (time.time() - start) / 60**2))
buffer += recv.decode()
buffer, commands = SearchForFullCommand(buffer)
if commands:
for n, command in enumerate(commands):
Log('Received full command #%d: %s' % (n, command))
send = COMMAND_START_CHAR+str(x)+COMMAND_END_CHAR
try:
sock.send(send)
except (bluetooth.btcommon.BluetoothError) as e:
Log('Failed to send %s: %s' % (send, e))
sock.close()
sock = ConnectBluetoothRetry(bd_addr, port, 10)
Log('Sent %s' % send)
x += 1
time.sleep(1)
main()
工作正常时，python日志文件是这样的。
.. b'646>' (len=4) after running for 0.843 hours
Received full command #0: 646
Sent <2526>
.. b'<647>' (len=5) after running for 0.843 hours
Received full command #0: 647
Sent <2527>
.. b'<' (len=1) after running for 0.844 hours
Sent <2528>
.. b'648>' (len=4) after running for 0.844 hours
然后，我发现它已经停止工作了，我杀了它，然后重新启动了它。
KeyboardInterrupt
Started at 2020-05-03 11:15:07
Failed to connect: [Errno 16] Device or resource busy
Failed to connect: [Errno 16] Device or resource busy
Failed to connect: [Errno 16] Device or resource busy
Failed to connect: [Errno 16] Device or resource busy
Failed to connect: [Errno 16] Device or resource busy
Failed to connect: [Errno 16] Device or resource busy
Failed to connect: [Errno 16] Device or resource busy
Failed to connect: [Errno 16] Device or resource busy
Failed to connect: [Errno 16] Device or resource busy
Failed to connect: [Errno 16] Device or resource busy
Failed to connect after 10 seconds
我再试一次..:
Started at 2020-05-03 11:15:42
Failed to connect: [Errno 112] Host is down
Failed to connect: [Errno 112] Host is down
Failed to connect: [Errno 112] Host is down
Connected after 3 seconds
.. b'1146><1147><1148><1149><1150><1151><1152><1153><1154><1155><1156><1157><1158><1159><1160><1161><1162><1163><1164><1165><1166><1' (len=127) after running for 0.005 hours
Received full command #0: 1147
Received full command #1: 1148
Received full command #2: 1149
...它又运行了一两个小时，然后又挂掉了 我并没有实际移动发送器或接收器 - 它们彼此相距不到一英尺 - 所以这不是范围。虽然我已经尝试过断开Arduino的连接，并重新给它供电，它们确实在仍在运行的Python进程中重新连接，没有问题。
Arduino的代码，虽然我不认为它是相关的，在这里。
long n = 1;
void setup()
{
Serial.begin(9600);
// HC-05 default serial speed for communcation mode is 9600
Serial1.begin(9600);
}
void loop()
{
Serial1.print("<");
Serial1.print(n);
Serial1.print(">");
if(Serial1.available() > 0){ // Checks whether data is comming from the serial port
Serial.println(Serial1.readString());} // Reads the data from the serial port
delay(1000);
n++;
}
谢谢你的帮助和建议
尽管我用了几天不同的方法&努力，还是无法让socket连接持续超过几个小时；我之所以走入socket兔子洞，只是因为我无法弄清楚如何通过蓝牙使用pySerialTransfer，甚至只是串行。
所以，回到串口的方法，经过更多的努力和调查，我最终能够让这种方法在Arduino上的Raspberry Pi & HC-05之间进行稳定的蓝牙连接（超过1天的时间）。
代码是 此处.