WiFi

Part 1 - Connecting to Wi-Fi

The Pico W uses the network module for Wi-Fi.

import network
import time

SSID = "your_wifi_name"
PASSWORD = "your_wifi_password"

wlan = network.WLAN(network.STA_IF)
wlan.active(True)
wlan.connect(SSID, PASSWORD)

print("Connecting to Wi-Fi", end="")
while not wlan.isconnected():
    print(".", end="")
    time.sleep(0.5)
print("\nConnected!")
print("IP address:", wlan.ifconfig()[0])

Notes:

Use wlan.ifconfig() to get (ip, subnet, gateway, dns).
Connection loops are common; add a timeout in production.

Part 2 - Talking to Public APIs

Public APIs Resource

A great resource is the Public APIs repo. It lists hundreds of free, open APIs - weather, astronomy, jokes, space, finance, etc.

Fetching Data (JSON)

MicroPython includes a minimal urequests library (install it if your firmware doesn't have it).

Example: Fetching a random joke from https://official-joke-api.appspot.com/random_joke

import network
import urequests
import time

# --- connect to wifi ---
SSID = "your_wifi_name"
PASSWORD = "your_wifi_password"

wlan = network.WLAN(network.STA_IF)
wlan.active(True)
wlan.connect(SSID, PASSWORD)
while not wlan.isconnected():
    time.sleep(0.5)

# --- API request ---
url = "https://official-joke-api.appspot.com/random_joke"
response = urequests.get(url)
data = response.json()
response.close()

print("Joke:", data["setup"])
print("Punchline:", data["punchline"])

Example: NASA Astronomy Picture of the Day

This requires a free API key (sign up at https://api.nasa.gov).

import urequests

API_KEY = "DEMO_KEY"  # replace with your key
url = f"https://api.nasa.gov/planetary/apod?api_key={API_KEY}"

resp = urequests.get(url)
info = resp.json()
resp.close()

print("Title:", info["title"])
print("Date:", info["date"])
print("URL:", info["url"])
print("Explanation:", info["explanation"])

Exercises - Public API Practice

Weather Fetcher Use Open-Meteo (no API key) to get the current temperature in your city.
Crypto Price Display Use CoinGecko API to fetch Bitcoin and Ethereum prices in USD.
SpaceX Launch Info From https://api.spacexdata.com/v4/launches/next, print mission name, date, and rocket ID.
Trivia Game Use Open Trivia Database to get 5 random questions. Ask the user to answer via REPL.
Daily Cat Picture Use The Cat API to fetch a random cat image URL and print it.

Part 3 - Running a server on the Pico

import network, socket, time, json

# --- Wi-Fi ---
SSID = "your_wifi_name"
PASSWORD = "your_wifi_password"

def wifi_connect():
    wlan = network.WLAN(network.STA_IF)
    wlan.active(True)    
    wlan.connect(SSID, PASSWORD)
    while not wlan.isconnected():
        time.sleep(0.2)
    return wlan

wlan = wifi_connect()
HOST = wlan.ifconfig()[0]
print("Pico listening at http://%s:80" % HOST)

# --- HTTP helpers ---
def http_response(conn, code=200, ctype="application/json", body="{}"):
    msg = "HTTP/1.1 %d OK\r\nContent-Type: %s\r\nAccess-Control-Allow-Origin: *\r\nContent-Length: %d\r\n\r\n%s" % (
        code, ctype, len(body), body)
    conn.sendall(msg)

def parse_request(req_bytes):
    try:
        head = req_bytes.decode().split("\r\n")[0]
        method, path, _ = head.split(" ")
        return method, path
    except:
        return None, None

def query_value(path, key, default=None):
    if "?" not in path: return default
    qs = path.split("?", 1)[1]
    for pair in qs.split("&"):
        if "=" in pair:
            k, v = pair.split("=", 1)
            if k == key: return v
    return default

# --- Server loop ---
addr = socket.getaddrinfo("0.0.0.0", 80)[0][-1]
s = socket.socket()
s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
s.bind(addr)
s.listen(1)

value=1
while True:
    conn, _ = s.accept()
    try:
        req = conn.recv(1024)
        method, path = parse_request(req)
        if not method:
            http_response(conn, 400, "text/plain", "Bad Request")
            continue

        if path.startswith("/get"):
            http_response(conn, body=json.dumps({"val": value}))

        elif path.startswith("/set"):
            value = int(query_value(path, "val", "0"))
            http_response(conn, 200, "text/plain", f"Ok! Set value to {value}")

        else:
            http_response(conn, 200, "text/plain",
                          "Endpoints: /get, /set?val={int}")
    except Exception as e:
        http_response(conn, 500, "text/plain", "Error: %s" % e)
    finally:
        conn.close()

Exercises

Smart Sensor Create an API to retrieve sensor data.
Smart LED Create an API to control a LED.
Communication Make a request to another pico!

Part 4 - Creating a Local Flask Server

We'll now run a Flask server on your PC and have the Pico W connect to it.

Install Flask

On your PC:

pip install flask

Minimal Flask Server (`server.py`)

from flask import Flask, request, jsonify

app = Flask(__name__)

# Example data store
messages = []

@app.route("/")
def index():
    return "Hello from Flask!"

@app.route("/api/echo", methods=["GET"])
def echo():
    msg = request.args.get("msg", "")
    return jsonify({"you_sent": msg})

@app.route("/api/messages", methods=["POST"])
def add_message():
    content = request.json
    messages.append(content)
    return jsonify({"status": "ok", "count": len(messages)})

@app.route("/api/messages", methods=["GET"])
def get_messages():
    return jsonify(messages)

if __name__ == "__main__":
    app.run(host="0.0.0.0", port=5000)

Run with:

python server.py

Pico W - Talking to Local Flask Server

Replace SERVER_IP with your computer's local IP (e.g., 192.168.1.100).

import network
import urequests
import time

SSID = "your_wifi_name"
PASSWORD = "your_wifi_password"
SERVER_IP = "192.168.1.100"

wlan = network.WLAN(network.STA_IF)
wlan.active(True)
wlan.connect(SSID, PASSWORD)
while not wlan.isconnected():
    time.sleep(0.5)

# GET request with query param
url = f"http://{SERVER_IP}:5000/api/echo?msg=HelloPico"
r = urequests.get(url)
print(r.json())
r.close()

# POST request with JSON body
data = {"from": "Pico W", "text": "Hi server!"}
url = f"http://{SERVER_IP}:5000/api/messages"
r = urequests.post(url, json=data)
print(r.json())
r.close()

# GET messages
r = urequests.get(url)
print(r.json())
r.close()

Exercises - Flask Interaction

Temperature Logger Create a /api/temp endpoint in Flask that stores temperature readings from the Pico W (fake or real). Pico sends a reading every 10 seconds.
LED Control Add a /api/led endpoint that accepts "on"/"off" in JSON. Pico polls this endpoint every second and turns an onboard LED on/off accordingly.
Two-Way Chat Pico sends text to Flask, Flask stores it, and Pico retrieves all messages every 5 seconds.
API Bridge Flask fetches data from a public API (e.g., weather) and serves it locally. Pico only talks to Flask, not the internet directly.
Mini Game Leaderboard Pico sends {player, score} to Flask; Flask stores and returns top 5 scores.

Part 1 - Connecting to Wi-Fi​

Part 2 - Talking to Public APIs​

Public APIs Resource​

Fetching Data (JSON)​

Example: NASA Astronomy Picture of the Day​

Exercises - Public API Practice​

Part 3 - Running a server on the Pico​

Exercises​

Part 4 - Creating a Local Flask Server​

Install Flask​

Minimal Flask Server (server.py)​

Pico W - Talking to Local Flask Server​

Exercises - Flask Interaction​