bluetooth: retrieving asynchronous data

[qcalv]

Hi everyone,

Im starting to program in Python with a Nokia N95, and I would like to have some tips. I want basically retrieve Data through a Bluetooth connection but asynchronously. I want to be able to do whatever while im not receiving any data, but if one comes, i stop what im doing and i get the data. Ive been use to program microcontroller, etc... and u can do that very easily with interruption.

But in python, on symbian system, thats totally different, Ive been reading a lot about Twisted, Asyncore, or select() to use either asynchronous socket, or thread. But i still didnt figure out how to do that, and with Bluetooth. If someone could light this up and help me that would be great.

Cheers,
Fran

[simo.salminen]

Get started on pys60, play with example programs. Using bluetooth socket is similar to using regular tcp socket.

This might be bit confusing. So just get it started. Make a simplest program receiving/sending data, after that lets see further.

You must likely cant use twisted, asyncore or select on pys60, but in practice this might not be a problem.

[qcalv]

Hey simo!
I already started!! But I didnt show my code, that's why I asked how could I get further, I already communicate with my pc, but in a synchronous way...

Using Tcp socket wont help so much, because Ive never really done that, it's just that i do not know where to start with the asynchronous thing, like what should i create, which properties, etc... There is plenty of things on google, its just not so clear what i need and what i dont.


Thanks!!

fran

Here is my simple code...

#Api importations
import e32 
import appuifw
import TopWindow
import graphics
import socket
#Functions implementation

	#Exit the script

def quit():
	print "Socket closed"
	try:
		sock.close()
	except NameError:
		appuifw.note(u"Bluetooth connection not opened.","info")
	window.hide()
	app_lock.signal()

	#Choose the service

def choose_service(services):
	names=[]
	channels=[]
	for name, channel in services.items():
		names.append(name)
		channels.append(channel)
	index=appuifw.popup_menu(names,u"Choose service")
	return channels[index]

	#Connect to a peripherique
	
def connect():
	global sock
	#adress, services=socket.bt_discover()
	#print(adress)
	#channel=choose_service(services)
	#print(channel)
	sock=socket.socket(socket.AF_BT, socket.SOCK_STREAM)
	sock.connect(('00:0e:9b:d9:5d:a2',1))	

def receive():
	global sock
	data=sock.recv(1)
	if data=="1":
		appuifw.note(u"I receive 1","info")
	elif data=="0":
		appuifw.note(u"I received 0","info")
		
def bt_send_data():
	sock.send("Message sent!")
	receive()
	
#Code implementation
global sock
appuifw.app.menu=[(u"Send message",bt_send_data),
				(u"Connect",connect)]
appuifw.app.screen="large"

#Start
app_lock=e32.Ao_lock()
 
appuifw.app.exit_key_handler=quit
#End
app_lock.wait()

[gaba88]

Hi everyone,

Im starting to program in Python with a Nokia N95, and I would like to have some tips. I want basically retrieve Data through a Bluetooth connection but asynchronously. I want to be able to do whatever while im not receiving any data, but if one comes, i stop what im doing and i get the data. Ive been use to program microcontroller, etc... and u can do that very easily with interruption.

But in python, on symbian system, thats totally different, Ive been reading a lot about Twisted, Asyncore, or select() to use either asynchronous socket, or thread. But i still didnt figure out how to do that, and with Bluetooth. If someone could light this up and help me that would be great.

Cheers,
Fran

hi Fran
welcome to the python dibo please have a look at this
hope this will help you.
have a ffedback

[qcalv]

Hi gaba88,

This is already what I did in the code, but the thing is that I do not want to receive the Data only when I call the function receive() but at any time. I want to do different operations in the main loop, and I want a sort of thread (Im not sure if this is what i need) in the background taking care of any incoming Data on the bluetooth port. Is it possible?

fran

[gaba88]

Hi gaba88,

This is already what I did in the code, but the thing is that I do not want to receive the Data only when I call the function receive() but at any time. I want to do different operations in the main loop, and I want a sort of thread (Im not sure if this is what i need) in the background taking care of any incoming Data on the bluetooth port. Is it possible?

fran

hi fran again
why dont you make your function run in a loop.

[qcalv]

hi fran again
why dont you make your function run in a loop.

Well, I dont like it. For my application, I still dont know if i will have a global loop or not, and I prefer to use background process rather than a global loop. Of course, if I have to, like if it doesnt make any sense to create a thread, then Ill do that.

But I want to be sure, there is no other way to do it, , thanks though.

fran

[jtullis]

I think we're having a parallel discussion on this thread

As far as I can see there doesn't seem to be an easy way for a function to spring to life whenenver the bt socket receives some data. In VB for example I use:

Private Sub DataReceived(ByVal sender As Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) Handles serialPort.DataReceived