Simple Lopy to Lopy via WiFi

[p.m.97]

Hi, I have some trouble to connect my two lopy4 via WiFi.
Here is receiver code:

import socket
import pycom

pycom.heartbeat(False)
s = socket.socket()
port = 80 
s.bind(('0.0.0.0',port))

print("Bind")
s.listen(5)
print("Listen")
while True:
   pycom.rgbled(0xFFFFFF)  # Blue
   c, addr = s.accept()
   print('Connection from :', addr)
   pycom.rgbled(0x00FF00)  # Green
   data = c.recv(64)
   print(data)
   c.send(b'Hello')
   

And this is sender code

from network import WLAN
import pycom
import machine
import socket

#Si connette ad una rete con un certo ssid e una certa password

ssid = "****"  #ssid of the other lopy
password = "*****" #password of the other lopy

pycom.heartbeat(False)
pycom.rgbled(0xFF0000)  # Red led at start
wlan = WLAN(mode=WLAN.STA)
nets = wlan.scan()
s = socket.socket()

for net in nets:
    if net.ssid == ssid:
        print("Found network: " + net.ssid)
        wlan.connect(net.ssid, auth=(net.sec, password), timeout=5000)
    
        while not wlan.isconnected():
            machine.idle() # save energy
        if wlan.isconnected() == True:
                print('WLAN connection succeeded!')
                print(wlan.ifconfig())
                while True:
                    b = bytes("Hello",'utf-8')
                    s.sendall(b)   #send butes
                    pycom.rgbled(0xFFFF00)
                    buffer = s.recv(64) #receive bytes
                    print(buffer) #print bytes received

        else:
                print("WLAN connection error")

When the sender codes arrive at line "s.sendall(b)", it gives me OS ERROR: 128, but I don't understand why. Can anyone help me?

[p.m.97]

Thanks @crumble and @timh for your answers!
I've changed my code, because I want to implement a WiFi Direct between my two Lopy4 ( so one act like AP, and the other like STA). I have changed my code as you advised me:

Server Main

import usocket as socket
import machine
from network import WLAN


wlan = WLAN()  # get current object, without changing the mode
if machine.reset_cause() != machine.SOFT_RESET:
    wlan.init(mode=WLAN.AP, ssid='Lopy-wlan', auth=(WLAN.WPA2,'www.pycom.io'), channel=10, antenna=WLAN.INT_ANT)


    myconfig = wlan.ifconfig()
    lst_myconfig = list(myconfig)
    lst_myconfig[0] = '192.168.0.20'
    myconfig = tuple(lst_myconfig)
    wlan.ifconfig(config=myconfig)
    print("Wlan configuration", myconfig)


s = socket.socket()
s.bind((lst_myconfig[0],2000))
s.listen(5)




c, addr = s.accept()     # Establish connection with client.
print ('Got connection from', addr)
c.send(b'Thank you for connecting')   # Send bytes
c.close()

Client Main

from network import WLAN
import pycom
import machine
import socket


ssid1 = "Lopy-wlan"
password = "www.pycom.io"

wlan = WLAN(mode=WLAN.STA) #station
nets = wlan.scan()
s  = socket.socket()  #create socket

for net in nets:
    if net.ssid == ssid1:
        print("Found network: " + net.ssid)
        wlan.connect(net.ssid, auth=(net.sec, password), timeout=5000) #connected to lopy AP

        while not wlan.isconnected():
            machine.idle() # save energy
        if wlan.isconnected() == True:
                print('WLAN connection succeeded!')




s.connect(socket.getaddrinfo('192.168.0.20',2000)[0][-1])

b = bytes("Hello",'utf-8')
s.sendall(b)   #send bytes
buffer = s.recv(64) #receive bytes
print(buffer) #print bytes received
s.close()

I've upload Server code on my Lopy server, then I run Client code on my Lopy client, but when I try to connect the socket ( with s.connect(...)) I have OSError: -1.

I've seached on google but I did not find anything.

What can it be?

[crumble]

@p-m-97

The socket is not connected. WiFi communication is point2point by default. So you have to provide a target adress and port.

Set up an own network with fix IP numbers. This will be the easiest way to start. You can switch to broadcast, after you managed the p2p communication.

[timh]

@p-m-97 Maybe you haven't supplied all of your code, but a few things stand out.

In your sender code you don't actually connect to anything with the socket.

Somewhere you need to call sock.connect(addr)

In addition in your listener code, you don't connect to the wifi network and that should occur before you bind.