Send message over bluetooth with Python 3

Question

I am currently trying to send a message from Python 3 to a Arduino (with HC-06). I've managed to establish a connection but I can't seem to find the right way to send a message.

Here is the code I use to setup the connection (I'm using PyBluez for bluetooth):

import sys
import bluetooth

bd_addr = '[MAC-address for HC-06]'
port = 1
sock = bluetooth.BluetoothSocket(bluetooth.RFCOMM)
sock.connect((bd_addr,port))

To send I'm trying:

sock.send("2")

Which throws the error: "TypeError: Expecting byte-buffer, got str".

Also tried:

sock.send(str('2'))

It also throws an error: "TypeError: Expecting byte-buffer, got str".

I've tried a bunch of other like "sock.send(2)", "sock.send(b'2')", bytearray, "sock.send(bytes(["2"]))". Basicly, whatever datatype I'm trying to send it demands another.

I've managed to send all my commands (only 1 and 2 at the moment) via a Bluetooth-terminal on my Android phone so there is no problem on the Arduino site.

There is a lot of guides out there with examples that I'm not able to replicate. Can anyone please tell me how I send basic commands? Am I even close to the answer?

EDIT: I've now tried "sock.send("2".encode())" and it also throws an error: "TypeError: data must be string, was class 'bytes'"

Using another ide gave me more specific information about the errors:

sock.send("2"): Warning (from warnings module): File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/PyBluez-0.22-py3.6.egg/lightblue/_bluetoothsockets.py", line 737 Foundation.NSData.alloc().initWithBytes_length_(data, len(data)), UninitializedDeallocWarning: leaking an uninitialized object of type _NSPlaceholderData Traceback (most recent call last): File "", line 1, in sock.send("2") File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/PyBluez-0.22-py3.6.egg/bluetooth/osx.py", line 122, in send return self._sock.send(data) File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/PyBluez-0.22-py3.6.egg/lightblue/_bluetoothsockets.py", line 524, in send result = self.__conn.write(writebuf[:sendbytecount]) File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/PyBluez-0.22-py3.6.egg/lightblue/_bluetoothsockets.py", line 737, in write Foundation.NSData.alloc().initWithBytes_length_(data, len(data)), TypeError: Expecting byte-buffer, got str

sock.send("2".encode()): Traceback (most recent call last): File "", line 1, in sock.send("2".encode()) File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/PyBluez-0.22-py3.6.egg/bluetooth/osx.py", line 122, in send return self._sock.send(data) File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/PyBluez-0.22-py3.6.egg/lightblue/_bluetoothsockets.py", line 487, in send raise TypeError("data must be string, was %s" % type(data)) TypeError: data must be string, was class 'bytes'

I am starting to doubt the library. It's totally possible that I managed to do something wrong when installing PyBluez. I'm gonna see if it might work on my Raspberry Pi 3.

Answer 1

Solution

When you send data over a socket you have to encode it or its gonna throw a byte buffer error. When you send data over the socket just use.

sock.send("2".encode())