Rfcomm Example

README.md

Bluetooth Communication

btrelay.service

[Unit]
Description=BlueTooth Relay Service
Wants=bluetooth.service
After=bluetooth.service

[Service]
ExecStart=/home/pi/projects/bluetooth/rfcomm-server.py
Restart=on-failure

[Install]
WantedBy=multi-user.target

inquiry.py

import bluetooth

print("performing inquiry...")

nearby_devices = bluetooth.discover_devices(duration=8, lookup_names=True, flush_cache=True, lookup_class=False)

print("found %d devices" % len(nearby_devices))

for addr, name in nearby_devices:
    try:
        print("  %s - %s" % (addr, name))
    except UnicodeEncodeError:
        print("  %s - %s" % (addr, name.encode('utf-8', 'replace')))

rfcomm-client.py

# file: rfcomm-client.py
# auth: Albert Huang <albert@csail.mit.edu>
# desc: simple demonstration of a client application that uses RFCOMM sockets
#       intended for use with rfcomm-server
#
# $Id: rfcomm-client.py 424 2006-08-24 03:35:54Z albert $

from bluetooth import *
import sys

if sys.version < '3':
    input = raw_input

addr = None

if len(sys.argv) < 2:
    print("no device specified.  Searching all nearby bluetooth devices for")
    print("the SampleServer service")
else:
    addr = sys.argv[1]
    print("Searching for SampleServer on %s" % addr)

# search for the SampleServer service
uuid = "94f39d29-7d6d-437d-973b-fba39e49d4ee"
service_matches = find_service( uuid = uuid, address = addr )

if len(service_matches) == 0:
    print("couldn't find the SampleServer service =(")
    sys.exit(0)

first_match = service_matches[0]
port = first_match["port"]
name = first_match["name"]
host = first_match["host"]

print("connecting to \"%s\" on %s" % (name, host))

# Create the client socket
sock=BluetoothSocket( RFCOMM )
sock.connect((host, port))

print("connected.  type stuff")
while True:
    data = input()
    if len(data) == 0: break
    sock.send(data)

sock.close()

rfcomm-server.py

#!/usr/bin/python3
# file: rfcomm-server.py
# auth: Albert Huang <albert@csail.mit.edu>
# desc: simple demonstration of a server application that uses RFCOMM sockets
#
# $Id: rfcomm-server.py 518 2007-08-10 07:20:07Z albert $
from threading import Thread
from bluetooth import *
import RPi.GPIO as GPIO

OUT_PIN = 4

def handle(client_sock):
    print("Accepted connection from ", client_info)
    try:
        while True:
            data = client_sock.recv(1024).decode("utf-8")
            if len(data) == 0: break
            print("received [%s]" % data)

            if data == "on":
                print("Turning %s on" % OUT_PIN)
                GPIO.output(OUT_PIN, GPIO.HIGH)
            elif data == "off":
                print("Turning %s off" % OUT_PIN)
                GPIO.output(OUT_PIN, GPIO.LOW)
            client_sock.send(data)
    except IOError as err:
        print(err)
    print("disconnected")
    client_sock.close()

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, "SampleServer",
                   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)

try:
    GPIO.setmode(GPIO.BCM)
    GPIO.setup(OUT_PIN, GPIO.OUT)
    while True:
        client_sock, client_info = server_sock.accept()
        handle(client_sock)
except KeyboardInterrupt:
    pass
finally:
    server_sock.close()
    GPIO.cleanup()
    print("all done")