Hi there,

I used to connect a generic Bluetooth dongle (ORICO-BTA-508) for connection to a device under development. The device under development is a SPP profile device, so it just provides a simple serial interface. The bluepy script in use (developed with help of http://ianharvey.github.io/bluepy-doc/index.html) is straight and simple:

!/usr/bin/env python3

""" \file io.py Communication helper

opens bluetooth connection to already bonded FL500C
prior connection can succeed a blescan has to be performed (needs sudo)
prints "DATA" when ready for communication
reads from STDIN in Format x01x03xFF..
waits for response
prints out response in format 01 03 FF
on timeout prints out nothing (This behaviour is made as similar to spp_client as possible to reduce adaption works) """ import bluepy.btle as btle import fileinput import re import sys import time from binascii import hexlify

SPP_SERVICE = "4880c12cfdcb40778920a450d7f9b907" SPP_DATA = "fec26ec46d7144429f8155bc21d658d6" DeviceName = btle.UUID(0x2A00) FirmwareRev = btle.UUID(0x2A26) Manufacturer = btle.UUID(0x2A29)

DEFAULT_BLE_CHUNK = 247 BLE_NOTIFICATION_TIMEOUT = 1.0 class BLEDongleDelegate(btle.DefaultDelegate):

def __init__(self, dongle):
    btle.DefaultDelegate.__init__(self)
    self.dongle = dongle
    self.dongle.result = bytearray( [] )
    self.dongle.timeout = BLE_NOTIFICATION_TIMEOUT
    print("init dongle: %f" % self.dongle.timeout)

def handleNotification(self, cHandle, data):
    #print "notification got"
    #self.dongle.result += bytearray(data)
    for x in bytearray(data):
        print("0x%02x" % x, end = " ")
    if len(data) == 244:    # this means the MTU (including 3 Bytes Overhead) is complete and
        self.dongle.device.waitForNotifications(self.dongle.timeout) # there might be more data
    else:
        print("") # end with line break

class myFL500C:

def getChar(self, concreteuuid):
    printname = concreteuuid.getCommonName()
    value = self.device.getCharacteristics(uuid=concreteuuid)[0].read()
    print("Characteristic: \"%s\" = %s, len:%i" % (printname, value, len(value)))

def __init__(self, bleAddress, debug=False):
    self.device = btle.Peripheral(bleAddress, addrType=btle.ADDR_TYPE_PUBLIC, iface=0)
    myobj = self.device.getCharacteristics()

    self.getChar(DeviceName)
    self.getChar(FirmwareRev)
    self.getChar(Manufacturer)
    time.sleep(1)
    self.device.setDelegate(BLEDongleDelegate(self))
    print("init Fl500C :%f" % self.timeout)
    self.device.setMTU(DEFAULT_BLE_CHUNK)
    self.service = self.device.getServiceByUUID(SPP_SERVICE)

    self.writeCharacteristic = self.service.getCharacteristics(forUUID=SPP_DATA)[0]
    #self.device.writeCharacteristic(self.writeCharacteristic.valHandle + 1, b"\x01") #, withResponse=True

    self.debug = debug
    self.opened = True

def exchange(self, apdu):
    if self.debug:
       print("=> %s" % hexlify(apdu))
    offset = 0
    self.result = ""
    while(offset < len(apdu)):
        #if self.debug:
        #    print("=> %s" % hexlify(apdu[offset:offset + DEFAULT_BLE_CHUNK]))
        data = apdu[offset:offset + DEFAULT_BLE_CHUNK]
        self.writeCharacteristic.write(data, withResponse=True)
        #print "written"
        offset += DEFAULT_BLE_CHUNK
    self.device.waitForNotifications(self.timeout)

def close(self):
    if self.opened:
        try:
            self.peripheral.disconnect()
        except:
            pass
    self.opened = False

if len(sys.argv) != 2: print("syntax: %s " % sys.argv[0]) sys.exit() else: MAC = sys.argv[1] print("connecting %s" % MAC) sys.argv = [sys.argv[0]]

dongle = myFL500C(MAC)

try: print("starting Stdin-Thread") print("DATA") for fileinput_line in fileinput.input(): if 'quit' == fileinput_line.rstrip(): break if 'timeout' == fileinput_line[:7]: cols=re.split("=", fileinput_line) dongle.timeout = float(cols[1]) continue byte_array = fileinput_line.rstrip() cols=re.split("x", byte_array) if len(cols) > 1: cols=cols[1:] myBytes = bytearray() for n in cols: myBytes += bytearray.fromhex(n)

    dongle.exchange( myBytes )

except KeyboardInterrupt:

User interrupt the program with ctrl+c

print("Done")
sys.exit()

finally: dongle.close() ` I run that script on Raspberry Pi 3 after I have verified the device is advertising using blescan.

But since i have upgraded to Python 3.7 (and after I've adapted that scripts syntax), the connection comes up in 1 of 5 tries, only. Before the upgrade bluepy was run with Python 2.7 and it failed only rarely to establish a connection, which was workarounded by at most 1 retry.

I found no reason yet (comparing logs of btmon, comparing a working with a failing attempt), except that it seems to struggle for timeouts and disconnects before the connection is secured.

Expected (and rarely seen outputs) of SPP_Client.py :

./SPP_Client 11:11:11:11:11:11 connecting 11:11:11:11:11:11 Characteristic: "Device Name" = b'FL5C-10000006\x00\x01\x00\x02\x01\x06', len:19 Characteristic: "Firmware Revision String" = b'1.0.1\x00\x00\x00\x00\x00\x00\x00\x00\x00', len:14 Characteristic: "Manufacturer Name String" = b'SICK ', len:12 init dongle: 1.000000 init Fl500C :1.000000 starting Stdin-Thread DATA x01x03x0CxB7x00x01x37x7C (user input, some telegram to send to the device) 0x01 0x03 0x02 0x03 0x41 0x78 0x84 (returned response from that device)

Usual error outputs of SPP_Client.py :

./SPP_Client 11:11:11:11:11:11 connecting 11:11:11:11:11:11 Traceback (most recent call last): File "./SPP_Client", line 105, in dongle = myFL500C(MAC) File "./SPP_Client", line 60, in init self.getChar(DeviceName) File "./SPP_Client", line 53, in getChar value = self.device.getCharacteristics(uuid=concreteuuid)[0].read() File "/usr/local/lib/python3.7/dist-packages/bluepy/btle.py", line 508, in getCharacteristics rsp = self._getResp('find') File "/usr/local/lib/python3.7/dist-packages/bluepy/btle.py", line 407, in _getResp resp = self._waitResp(wantType + ['ntfy', 'ind'], timeout) File "/usr/local/lib/python3.7/dist-packages/bluepy/btle.py", line 362, in _waitResp raise BTLEDisconnectError("Device disconnected", resp) bluepy.btle.BTLEDisconnectError: Device disconnected

Sometimes it generates a bit more of output:

./SPP_Client 11:11:11:11:11:11 connecting 11:11:11:11:11:11 Traceback (most recent call last): File "./SPP_Client", line 105, in dongle = myFL500C(MAC) File "./SPP_Client", line 60, in init self.getChar(DeviceName) File "./SPP_Client", line 53, in getChar value = self.device.getCharacteristics(uuid=concreteuuid)[0].read() File "/usr/local/lib/python3.7/dist-packages/bluepy/btle.py", line 508, in getCharacteristics rsp = self._getResp('find') File "/usr/local/lib/python3.7/dist-packages/bluepy/btle.py", line 407, in _getResp resp = self._waitResp(wantType + ['ntfy', 'ind'], timeout) File "/usr/local/lib/python3.7/dist-packages/bluepy/btle.py", line 361, in _waitResp self._stopHelper() File "/usr/local/lib/python3.7/dist-packages/bluepy/btle.py", line 293, in _stopHelper self._helper.stdin.flush() BrokenPipeError: [Errno 32] Broken pipe Exception ignored in: <function Peripheral.del at 0x76620780> Traceback (most recent call last): File "/usr/local/lib/python3.7/dist-packages/bluepy/btle.py", line 630, in del self.disconnect() File "/usr/local/lib/python3.7/dist-packages/bluepy/btle.py", line 453, in disconnect self._writeCmd("disc\n") File "/usr/local/lib/python3.7/dist-packages/bluepy/btle.py", line 305, in _writeCmd self._helper.stdin.flush() BrokenPipeError: [Errno 32] Broken pipe

Version infos:

pip list

bluepy 1.3.0 pip 20.3.4 RPi.GPIO 0.7.0

Bonding was accomplished using the interactive bluetoothctl. Some other information you might be interested in:

lsb_release -C Codename: buster uname -r 5.10.60-v7+

The device under development is stable meanwhile, connections using a mobile phone or an android tablet do work very well.

Any help or hint with this would be appreciated.

IanHarvey / bluepy

Issue with bluepy, SPP profile, security level 3, connection comes up rarely #457

!/usr/bin/env python3

User interrupt the program with ctrl+c