Connect and send data via WiFi from WiPy to LoPy

[amartinez]

Regarding the problems we found to do the same by BLE (https://forum.pycom.io/topic/1282/send-data-from-wipy-to-lopy-with-ble/6), I' m asking if it is possible to send data via WiFi from WiPy to LoPy.

Reading the documentation, it seems easy to connect, and then create a socket, but I prefer to ask you if it is possible before wasting my time...

Thank you.

[livius]

@amartinez
Yes, it is possible
But i tested this with 2xWipy2 without lopy
But it should work same.

[amartinez]

@livius thank you. Could you share any code to step on? Or any recommendations about the necessary code?
What WLAN mode have I to choose? And what about the network security?
I guess the connection is done similar than the example:

import network
import time
# setup as a station
wlan = network.WLAN(mode=network.WLAN.STA)
wlan.connect('your-ssid', auth=(network.WLAN.WPA2, 'your-key'))
while not wlan.isconnected():
    time.sleep_ms(50)
print(wlan.ifconfig())

# now use socket as usual
...

And then, how do I send the data?

[livius]

@amartinez
you can use STA_AP
or
in "server node" AP
in "client" node STA

on server you must listen
look here for sample
https://docs.python.org/2/howto/sockets.html
or
here
https://pymotw.com/2/socket/tcp.html

[amartinez]

@livius So, the server will be the listener (LoPy) and the Client sends the data (WiPy)?
It's a bit confusing because on BLE its the contrary...

In order to listen, have I to set an IP adress?

[robert-hh]

@amartinez The access point has to set an IP address. By default this is 192.168.4.1. The AP will also run an DHCP server, which distributes IP-addresses to the client. The Client has to connect to the AP.
It might be confusing that there are two layers of connection needed:

• One at the link level - Access point to Station (this is like plugging in a cable)
• One at the socket level - Client to server

[amartinez]

@robert-hh thank you Robert. The connection is set correctly, now let's try to send data.

Connection code:

WiPy (Client - STA mode, transmitter):

# WiPy sends data -> Client -> WLAN mode = STA
import network
import time
import pycom

# setup as a station
wlan = network.WLAN(mode=network.WLAN.STA)
wlan.connect('lopy-wlan', auth=(network.WLAN.WPA2, 'www.pycom.io'))
while not wlan.isconnected():
    time.sleep_ms(50)
print(wlan.ifconfig())
pycom.rgbled(0x007f00) # green
# now use socket as usual
...

LoPy (Server - AP mode, listener):

import network
import time
from network import WLAN
# setup as a station
wlan = network.WLAN(mode=network.WLAN.AP)
wlan.init(mode=WLAN.AP, ssid='lopy-wlan', auth=(WLAN.WPA2,'www.lopy.io'), channel=7, antenna=WLAN.INT_ANT)
#wlan.connect('your-ssid', auth=(network.WLAN.WPA2, 'your-key'))
while not wlan.isconnected():
    time.sleep_ms(50)
print(wlan.ifconfig())

[amartinez]

Update: It's not connecting really, I thought that it was printing the ifcongif but it's not. This is what it prints:

[livius]

@amartinez
for server node it is not good to have

while not wlan.isconnected():
    time.sleep_ms(50)

You do not connect wifi here only you start Access Point (AP) - look if it start on network list scan on client node side or your PC