WiFi Networking Examples - Raspberry Pi Pico 2W

The following short Python programs will demonstrate essential operation of the Raspberry Pi Pico 2W board. These use only the onboard hardware and the serial console. Each can be run by copying the program into code.py on the CIRCUITPY drive offered by the board. The text can be pasted directly from this page, or each file can be downloaded from the CircuitPython sample code folder on this site.

Related Pages

• Raspberry Pi 2W Pico

• CircuitPython Introduction

• Adafruit wifi module tutorial

• CircuitPython wifi module

• CircuitPython socketpool module

Scan WiFi

This script will report all networks visible to the WiFi chip on the Pi Pico 2W.

Direct download: scan_wifi.py.

# scan_wifi.py
# https://learn.adafruit.com/networking-in-circuitpython/networking-with-the-wifi-module

# to try this, copy it to the CIRCUITPY drive as code.py

import wifi
networks = []

print("Beginning WiFi network scan.")

for network in wifi.radio.start_scanning_networks():
    networks.append(network)

wifi.radio.stop_scanning_networks()

networks = sorted(networks, key=lambda net: net.rssi, reverse=True)

for network in networks:
    print("ssid:", network.ssid, "rssi:", network.rssi)

print("scan_wifi done.")

Identify WiFi MAC

This script will report the 48 bit hardware network address of the WiFi chip on the Pi Pico 2W. At CMU this string is required to register the device for the campus network using the GetOnline service provided by Computing Services.

It is short enough it can be pasted directly into the command line via your terminal emulator.

The mac_address property behaves like a bytestring with six values. The string formatter converts each byte value into a two-digit hex number, the list comprehension builds a list of these values, and the join operation concatenates the strings into the conventional form separated by colons.

Direct download: identify_wifi_MAC.py.

# identify_wifi_MAC.py

# Display the hardware address from the WiFi chip.
# This may be needed for requesting network access.

# To try this, copy it to the CIRCUITPY drive as code.py, or just paste it at the REPL command line.

import wifi
mac = ':'.join([("%02x" % b) for b in wifi.radio.mac_address])
print("WiFi MAC:", mac)

Ping Test

This script will connect to the campus CMU-DEVICE WiFi network and measure ping times to the main campus web server. This local network does not require a password but does require registration of the device WiFi MAC using GetOnline.

Direct download: ping_test.py.

# ping_test.py
# to try this, copy it to the CIRCUITPY drive as code.py

import time
import wifi
import ipaddress
import socketpool

# name of the host to ping
ping_host = "www.cmu.edu"

# fetch the device address from the WiFi module
mac = ':'.join([("%02x" % b) for b in wifi.radio.mac_address])
print("device WiFi MAC:", mac)

print("Attempting to connect to the campus CMU-DEVICE WiFi.")
wifi.radio.connect(ssid="CMU-DEVICE")

print("device IP addr:", wifi.radio.ipv4_address)

# use DNS to find the host address
pool = socketpool.SocketPool(wifi.radio)
addr = pool.getaddrinfo(ping_host, port=80)

# extract the host address field from the resulting list of tuples
host_ip = addr[0][4][0]

print("pinging", ping_host, "at", host_ip)
ip = ipaddress.ip_address(host_ip)

while True:
    print("ping time:", wifi.radio.ping(ip))
    time.sleep(5)