The wifi Module
The wifi module provides a simple interface between CircuitPython and the internet using WiFi. It is a built-in module on Espressif and Pico W boards.
Here are a couple of short examples from the guide Todbot's CircuitPython Tricks:
Scan Local WiFi Networks
import wifi
networks = []
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)
Displaying Your Local IP Address
This short program uses the wifi module to connect to the local network, using credentials you set up in a settings.toml file, and then gets the internet protocol (IP) address of your device and prints it out.
# settings.toml CIRCUITPY_WIFI_SSID = "PrettyFlyForAWiFi" CIRCUITPY_WIFI_PASSWORD = "mysecretpassword"
# code.py
import os, wifi
print("connecting...")
wifi.radio.connect(ssid=os.getenv('CIRCUITPY_WIFI_SSID'),
password=os.getenv('CIRCUITPY_WIFI_PASSWORD'))
print("my IP addr:", wifi.radio.ipv4_address)
Using adafruit_connection_manager
The adafruit_connection_manager library provides a simple way to get a socket pool or an SSL context (used for HTTPS requests). It supports using the wifi module , the ESP32SPI library, and can also work on the desktop using CPython ("regular" Python).
Example:
import wifi
import adafruit_connection_manager
import adafruit_requests
radio = wifi.radio
# Add code to make sure your radio is connected
pool = adafruit_connection_manager.get_radio_socketpool(radio)
ssl_context = adafruit_connection_manager.get_radio_ssl_context(radio)
requests = adafruit_requests.Session(pool, ssl_context)
requests.get("http://wifitest.adafruit.com/testwifi/index.html")
# Do something with response
The adafruit_requests Library
The adafruit_requests library provides functions similar to the CPython requests module, used for HTTP(S) commands.
# SPDX-FileCopyrightText: 2021 ladyada for Adafruit Industries
# SPDX-License-Identifier: MIT
# Updated for CircuitPython 9.0
"""WiFi Simpletest"""
import os
import adafruit_connection_manager
import wifi
import adafruit_requests
# Get WiFi details, ensure these are setup in settings.toml
ssid = os.getenv("CIRCUITPY_WIFI_SSID")
password = os.getenv("CIRCUITPY_WIFI_PASSWORD")
TEXT_URL = "http://wifitest.adafruit.com/testwifi/index.html"
JSON_GET_URL = "https://httpbin.org/get"
JSON_POST_URL = "https://httpbin.org/post"
# Initalize Wifi, Socket Pool, Request Session
pool = adafruit_connection_manager.get_radio_socketpool(wifi.radio)
ssl_context = adafruit_connection_manager.get_radio_ssl_context(wifi.radio)
requests = adafruit_requests.Session(pool, ssl_context)
rssi = wifi.radio.ap_info.rssi
print(f"\nConnecting to {ssid}...")
print(f"Signal Strength: {rssi}")
try:
# Connect to the Wi-Fi network
wifi.radio.connect(ssid, password)
except OSError as e:
print(f"❌ OSError: {e}")
print("✅ Wifi!")
print(f" | GET Text Test: {TEXT_URL}")
with requests.get(TEXT_URL) as response:
print(f" | ✅ GET Response: {response.text}")
print("-" * 80)
print(f" | GET Full Response Test: {JSON_GET_URL}")
with requests.get(JSON_GET_URL) as response:
print(f" | ✅ Unparsed Full JSON Response: {response.json()}")
print("-" * 80)
DATA = "This is an example of a JSON value"
print(f" | ✅ JSON 'value' POST Test: {JSON_POST_URL} {DATA}")
with requests.post(JSON_POST_URL, data=DATA) as response:
json_resp = response.json()
# Parse out the 'data' key from json_resp dict.
print(f" | ✅ JSON 'value' Response: {json_resp['data']}")
print("-" * 80)
json_data = {"Date": "January 1, 1970"}
print(f" | ✅ JSON 'key':'value' POST Test: {JSON_POST_URL} {json_data}")
with requests.post(JSON_POST_URL, json=json_data) as response:
json_resp = response.json()
# Parse out the 'json' key from json_resp dict.
print(f" | ✅ JSON 'key':'value' Response: {json_resp['json']}")
print("-" * 80)
print("Finished!")
Using MQTT
MQTT is a messaging protocol for communicating between two nodes on the internet. It is often used for Internet of Things (IoT) devices to pass data.
# Simple demo of MQTT client in CircuitPython with native WiFi (ESP32-S Series)
# 9 Oct 2021 - @todbot / Tod Kurt
# 31 July 2024 Anne Barela for Adafruit Industries
#
# This will connect to WiFi, then connect to an MQTT broker (shiftr.io was tested)
# and then listen to one MQTT feed while periodically publishing to another MQTT feed.
#
# Your settings.toml file contains something like:
# CIRCUITPY_WIFI_SSID = "myWiFiName"
# CIRCUITPY_WIFI_PASSWORD = "mywifipassword"
# mqtt_broker ="test.mosquitto.org"
# mqtt_port = "1883" # unencrytped, use 8883 for TLS encrypted
# mqtt_username = ""
# mqtt_password = ""
#
import os
import time
import ssl, socketpool, wifi
import adafruit_minimqtt.adafruit_minimqtt as MQTT
my_mqtt_topic_hello = "me/feeds/hello" # the topic we send on
my_mqtt_topic_light = "me/feeds/light" # the topic we receive on (could be the same)
# Connect to WiFi
print(f"Connecting to {os.getenv('CIRCUITPY_WIFI_SSID')}")
wifi.radio.connect(os.getenv("CIRCUITPY_WIFI_SSID"), os.getenv("CIRCUITPY_WIFI_PASSWORD"))
# Set up a MiniMQTT Client
mqtt_client = MQTT.MQTT(
broker=os.getenv("mqtt_broker"),
port=os.getenv("mqtt_port"),
username=os.getenv("mqtt_username"),
password=os.getenv("mqtt_password"),
socket_pool=socketpool.SocketPool(wifi.radio),
ssl_context=ssl.create_default_context(),
)
# Called when the client is connected successfully to the broker
def connected(client, userdata, flags, rc):
print("Connected to MQTT broker!")
client.subscribe( my_mqtt_topic_light) # say I want to listen to this topic
# Called when the client is disconnected
def disconnected(client, userdata, rc):
print("Disconnected from MQTT broker!")
# Called when a topic the client is subscribed to has a new message
def message(client, topic, message):
print("New message on topic {0}: {1}".format(topic, message))
val = 0
try:
val = int(message) # attempt to parse it as a number
except ValueError:
pass
print("setting LED to color:",val)
# led.fill(val) # if we had leds
# Set the callback methods defined above
mqtt_client.on_connect = connected
mqtt_client.on_disconnect = disconnected
mqtt_client.on_message = message
print("Connecting to MQTT broker...")
mqtt_client.connect()
last_msg_send_time = 0
while True:
print("waiting")
mqtt_client.loop(timeout=1) # see if any messages to me
if time.monotonic() - last_msg_send_time > 3.0: # send a message every 3 secs
last_msg_send_time = time.monotonic()
msg = "hi there! time is "+str(time.monotonic())
print("sending MQTT msg..", msg)
mqtt_client.publish( my_mqtt_topic_hello, msg )
Further Reading
ReadTheDocs
Third Party Guides
- Connect to Multiple WiFi Networks with your Raspberry Pi Pico W
- CircuitPython WiFi Manager - opens an access point to allow the user to configure the device to configure the device to connect to available WiFi networks. When the device is configured, it then connects to the first available matching network and hands over the control to your code.
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