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145 lines
5.0 KiB
Markdown
145 lines
5.0 KiB
Markdown
# WLAN
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The WLAN is a system feature of all Pycom devices, therefore it is enabled by default.
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In order to retrieve the current WLAN instance, run:
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```python
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>>> from network import WLAN
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>>> wlan = WLAN() # we call the constructor without params
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```
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The current mode \(`WLAN.AP` after power up\) may be checked by running:
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```python
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>>> wlan.mode()
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```
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{% hint style="danger" %}
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When changing the WLAN mode, if following the instructions below, the WLAN connection to the Pycom device will be broken. This means commands will not run interactively over WiFi.
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**There are two ways around this:**
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1. Put this setup code into the `boot.py` file of the Pycom device so that it gets executed automatically after reset.
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2. Duplicate the REPL on UART. This way commands can be run via Serial USB.
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## Connecting to a Router
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The WLAN network class always boots in `WLAN.AP` mode; to connect it to an existing network, the WiFi class must be configured as a station:
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```python
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from network import WLAN
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wlan = WLAN(mode=WLAN.STA)
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```
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Now the device may proceed to scan for networks:
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```python
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nets = wlan.scan()
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for net in nets:
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if net.ssid == 'mywifi':
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print('Network found!')
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wlan.connect(net.ssid, auth=(net.sec, 'mywifikey'), timeout=5000)
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while not wlan.isconnected():
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machine.idle() # save power while waiting
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print('WLAN connection succeeded!')
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break
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```
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## Assigning a Static IP Address at Boot Up
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If the users wants their device to connect to a home router upon boot up, using with a fixed IP address, use the following script as `/flash/boot.py`:
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```python
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import machine
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from network import WLAN
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wlan = WLAN() # get current object, without changing the mode
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if machine.reset_cause() != machine.SOFT_RESET:
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wlan.init(mode=WLAN.STA)
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# configuration below MUST match your home router settings!!
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wlan.ifconfig(config=('192.168.178.107', '255.255.255.0', '192.168.178.1', '8.8.8.8'))
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if not wlan.isconnected():
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# change the line below to match your network ssid, security and password
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wlan.connect('mywifi', auth=(WLAN.WPA2, 'mywifikey'), timeout=5000)
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while not wlan.isconnected():
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machine.idle() # save power while waiting
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```
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{% hint style="info" %}
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Notice how we check for the reset cause and the connection status, this is crucial in order to be able to soft reset the LoPy during a telnet session without breaking the connection.
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{% endhint %}
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## Multiple Networks using a Static IP Address
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The following script holds a list with nets and an optional list of `wlan_config` to set a fixed IP
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```python
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import os
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import machine
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uart = machine.UART(0, 115200)
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os.dupterm(uart)
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known_nets = {
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'<net>': {'pwd': '<password>'},
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'<net>': {'pwd': '<password>', 'wlan_config': ('10.0.0.114', '255.255.0.0', '10.0.0.1', '10.0.0.1')}, # (ip, subnet_mask, gateway, DNS_server)
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}
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if machine.reset_cause() != machine.SOFT_RESET:
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from network import WLAN
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wl = WLAN()
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wl.mode(WLAN.STA)
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original_ssid = wl.ssid()
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original_auth = wl.auth()
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print("Scanning for known wifi nets")
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available_nets = wl.scan()
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nets = frozenset([e.ssid for e in available_nets])
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known_nets_names = frozenset([key for key in known_nets])
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net_to_use = list(nets & known_nets_names)
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try:
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net_to_use = net_to_use[0]
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net_properties = known_nets[net_to_use]
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pwd = net_properties['pwd']
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sec = [e.sec for e in available_nets if e.ssid == net_to_use][0]
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if 'wlan_config' in net_properties:
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wl.ifconfig(config=net_properties['wlan_config'])
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wl.connect(net_to_use, (sec, pwd), timeout=10000)
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while not wl.isconnected():
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machine.idle() # save power while waiting
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print("Connected to "+net_to_use+" with IP address:" + wl.ifconfig()[0])
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except Exception as e:
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print("Failed to connect to any known network, going into AP mode")
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wl.init(mode=WLAN.AP, ssid=original_ssid, auth=original_auth, channel=6, antenna=WLAN.INT_ANT)
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```
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## Connecting to a WPA2-Enterprise network
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### Connecting with EAP-TLS:
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Before connecting, obtain and copy the public and private keys to the device, e.g. under location `/flash/cert`. If it is required to validate the server’s public key, an appropriate CA certificate \(chain\) must also be provided.
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```python
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from network import WLAN
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wlan = WLAN(mode=WLAN.STA)
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wlan.connect(ssid='mywifi', auth=(WLAN.WPA2_ENT,), identity='myidentity', ca_certs='/flash/cert/ca.pem', keyfile='/flash/cert/client.key', certfile='/flash/cert/client.crt')
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```
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### Connecting with EAP-PEAP or EAP-TTLS:
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In case of EAP-PEAP \(or EAP-TTLS\), the client key and certificate are not necessary, only a username and password pair. If it is required to validate the server’s public key, an appropriate CA certificate \(chain\) must also be provided.
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```python
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from network import WLAN
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wlan = WLAN(mode=WLAN.STA)
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wlan.connect(ssid='mywifi', auth=(WLAN.WPA2_ENT, 'username', 'password'), identity='myidentity', ca_certs='/flash/cert/ca.pem')
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```
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