Android – serial communication via Bluetooth using Python

How do you process and receive serial data via Bluetooth and python?

I'm trying to make a simple Python server that accesses data as explained here through Bluetooth

My server.py file sends a random number when sending the text "temp", which is:

#!/usr/bin/env python

import os
import glob
import time
import random

from bluetooth import *

def read_temp():
    return random.random()

server_sock=BluetoothSocket( RFCOMM )
server_sock.bind(("",PORT_ANY))
server_sock.listen(1)

port = server_sock.getsockname()[1]

uuid = "94f39d29-7d6d-437d-973b-fba39e49d4ee"

advertise_service( server_sock, "TestServer",
                   service_id = uuid,
                   service_classes = [ uuid, SERIAL_PORT_CLASS ],
                   profiles = [ SERIAL_PORT_PROFILE ], 
#                   protocols = [ OBEX_UUID ] 
                    )
while True:          
    print "Waiting for connection on RFCOMM channel %d" % port

    client_sock, client_info = server_sock.accept()
    print "Accepted connection from ", client_info

    try:
        data = client_sock.recv(1024)
        if len(data) == 0: break
        print "received [%s]" % data

        if data == 'temp':
            data = str(read_temp())+'!'
            client_sock.send(data)
        else:
            data = 'WTF!' 
            client_sock.send(data)
        print "sending [%s]" % data

    except IOError:
        pass

    except KeyboardInterrupt:

        print "disconnected"

        client_sock.close()
        server_sock.close()
        print "all done"

        break

When I first ran it, I got an error:

bluetooth.btcommon.BluetoothError: (2, 'No such file or directory')

You can fix Google shown by enabling compatibility mode and loading the serial configuration file by editing the file / lib / SYSTEMd / system / bluetooth.service and changing the line

ExecStart=/usr/lib/bluetooth/bluetoothd

To:

ExecStart=/usr/lib/bluetooth/bluetoothd -C

Then run sudo sdptool add sp

Now Python server.py seems to work normally, and I can pair the machine running it with my Android phone. However, it seems that I can't receive any data

I have tried to use Bluetooth terminal emulation applications, such as blueterm, BT simple terminal and Arduino BT, but when I connect to the server, enter the text and press enter, server.py does not respond. It will initially report "accepted connection..." and has received an empty string, but will receive nothing thereafter

Since no obvious errors were reported, I'm not sure how to diagnose the problem. How to determine whether the problem is in my Python code? Or Bluetooth configuration on the server? Or my Android phone?

resolvent:

The correct code is:

#!/usr/bin/env python
"""
A simple test server that returns a random number when sent the text "temp" via Bluetooth serial.
"""

import os
import glob
import time
import random

from bluetooth import *

server_sock = BluetoothSocket( RFCOMM )
server_sock.bind(("",PORT_ANY))
server_sock.listen(1)

port = server_sock.getsockname()[1]

uuid = "94f39d29-7d6d-437d-973b-fba39e49d4ee"

advertise_service( server_sock, "TestServer",
                   service_id = uuid,
                   service_classes = [ uuid, SERIAL_PORT_CLASS ],
                   profiles = [ SERIAL_PORT_PROFILE ], 
#                   protocols = [ OBEX_UUID ] 
                    )

print "Waiting for connection on RFCOMM channel %d" % port
client_sock, client_info = server_sock.accept()
print "Accepted connection from ", client_info

while True:          

    try:
        req = client_sock.recv(1024)
        if len(req) == 0:
            break
        print "received [%s]" % req

        data = None
        if req in ('temp', '*temp'):
            data = str(random.random())+'!'
        else:
            pass

        if data:
            print "sending [%s]" % data
            client_sock.send(data)

    except IOError:
        pass

    except KeyboardInterrupt:

        print "disconnected"

        client_sock.close()
        server_sock.close()
        print "all done"

        break