树莓派 Pico W WiFi 编程例程
示例 1：MicroPython — WiFi 连接 + 闪烁 LED
"""Pico W WiFi 连接 + 板载 LED"""
import network
import time
from machine import Pin
led = Pin("LED", Pin.OUT) # Pico W 板载 LED 用 "LED" 字符串
ssid = "你的WiFi名"
password = "你的WiFi密码"
wlan = network.WLAN(network.STA_IF)
wlan.active(True)
wlan.connect(ssid, password)
print("连接中...")
max_wait = 20
while max_wait > 0:
if wlan.status() < 0 or wlan.status() >= 3:
break
max_wait -= 1
led.toggle()
time.sleep(0.5)
if wlan.status() == 3:
led.on()
print(f"✅ 已连接！IP: {wlan.ifconfig()[0]}")
else:
led.off()
print(f"❌ 连接失败，状态码: {wlan.status()}")
示例 2：MicroPython — HTTP GET 请求（获取天气）
"""Pico W HTTP GET 获取网络时间"""
import network
import urequests
import time
# 先连接 WiFi（参考示例 1）
response = urequests.get("http://worldtimeapi.org/api/timezone/Asia/Shanghai")
if response.status_code == 200:
data = response.json()
print(f"北京时间: {data['datetime']}")
else:
print(f"请求失败: {response.status_code}")
response.close()
示例 3：MicroPython — MQTT 温湿度上报
"""Pico W + DHT22 → MQTT 上报温湿度"""
from machine import Pin
import network, time
from umqtt.simple import MQTTClient
import dht
# ----- WiFi 连接 -----
wlan = network.WLAN(network.STA_IF)
wlan.active(True)
wlan.connect("SSID", "PASSWORD")
while not wlan.isconnected():
time.sleep(0.5)
print(f"IP: {wlan.ifconfig()[0]}")
# ----- MQTT -----
MQTT_BROKER = "broker.emqx.io"
TOPIC = b"pico-w/sensors"
client = MQTTClient("pico-w-001", MQTT_BROKER)
client.connect()
print("MQTT 已连接")
# ----- DHT22 -----
sensor = dht.DHT22(Pin(4)) # GP4
while True:
try:
sensor.measure()
t = sensor.temperature()
h = sensor.humidity()
payload = f'{{"temp":{t:.1f},"humidity":{h:.1f}}}'
client.publish(TOPIC, payload)
print(f"上报: {payload}")
except Exception as e:
print(f"错误: {e}")
time.sleep(30)
示例 4：MicroPython — 简易 Web Server（GPIO 控制）
"""Pico W Web Server — 网页控制 LED"""
import network, socket
from machine import Pin
import time
led = Pin("LED", Pin.OUT)
# WiFi 连接（略）
# HTML 页面
html = """<!DOCTYPE html>
<html><head><meta charset="utf-8">
<meta name="viewport" content="width=device-width,initial-scale=1">
<title>Pico W</title></head>
<body>
<h1>Pico W LED 控制</h1>
<p><a href="/on"><button>LED ON</button></a></p>
<p><a href="/off"><button>LED OFF</button></a></p>
</body></html>"""
addr = socket.getaddrinfo('0.0.0.0', 80)[0][-1]
s = socket.socket()
s.bind(addr)
s.listen(1)
print(f"Web Server: http://{wlan.ifconfig()[0]}")
while True:
cl, addr = s.accept()
request = cl.recv(1024).decode()
print(f"请求: {request.split(chr(10))[0]}")
if '/on' in request:
led.on()
elif '/off' in request:
led.off()
cl.send('HTTP/1.1 200 OK\r\nContent-Type: text/html\r\n\r\n')
cl.send(html)
cl.close()
示例 5：MicroPython — BLE 外设（温度服务）
"""Pico W BLE 温度外设 — 手机可扫描并读取"""
import bluetooth
import struct
from machine import ADC
import time
# 环境温度服务 UUID (标准)
ENV_SENSE_UUID = bluetooth.UUID(0x181A)
TEMP_CHAR_UUID = bluetooth.UUID(0x2A6E)
class BLE_Temp:
def __init__(self):
self._ble = bluetooth.BLE()
self._ble.active(True)
self._ble.irq(self._irq)
self._register()
self._advertise()
def _register(self):
temp_char = (TEMP_CHAR_UUID, bluetooth.FLAG_READ | bluetooth.FLAG_NOTIFY)
service = (ENV_SENSE_UUID, (temp_char,))
((self._handle,),) = self._ble.gatts_register_services((service,))
def _advertise(self):
name = b"PicoW-Temp"
self._ble.gap_advertise(100000, b'\x02\x01\x06' +
struct.pack('BB', len(name)+1, 0x09) + name)
def _irq(self, event, data):
pass
def update_temp(self, temp_c):
"""更新温度值（单位: 0.01°C）"""
self._ble.gatts_write(self._handle,
struct.pack('<h', int(temp_c * 100)))
ble = BLE_Temp()
adc = ADC(4) # RP2040 内部温度传感器 (ADC4)
while True:
# RP2040 内部温度传感器粗略读取
raw = adc.read_u16()
voltage = raw * 3.3 / 65535
temp = 27 - (voltage - 0.706) / 0.001721
ble.update_temp(temp)
print(f"温度: {temp:.1f}°C")
time.sleep(2)
示例 6：MicroPython — WiFi + 看门狗（防死锁）
"""Pico W WiFi 看门狗自动重连"""
from machine import WDT, Pin
import network, time
wdt = WDT(timeout=8000) # 8 秒看门狗
led = Pin("LED", Pin.OUT)
wlan = network.WLAN(network.STA_IF)
wlan.active(True)
def connect_wifi():
wlan.connect("SSID", "PASSWORD")
for _ in range(20):
if wlan.isconnected():
return True
time.sleep(0.5)
return False
while True:
if not wlan.isconnected():
print("WiFi 断开，重连中...")
if connect_wifi():
print(f"重连成功 {wlan.ifconfig()[0]}")
else:
print("重连失败，30秒后重试")
time.sleep(30)
else:
led.toggle()
wdt.feed() # 喂狗
time.sleep(1)
⚠️ Pico W 编程要点
- 板载 LED 访问：MicroPython 用
Pin("LED", Pin.OUT)，C SDK 用 CYW43_WL_GPIO_LED_PIN。
- WiFi 和 BLE 不能同时使用：CYW43439 限制，需分时复用。
- MicroPython 内存紧张：264KB SRAM — 固件 ~100KB + WiFi 栈 ~60KB ≈ 仅剩 ~100KB 给用户代码。
- urequests 内存消耗大：大 JSON 响应可能导致 OOM，建议用
ujson 流式解析或缩小响应数据。
- OTA 更新：可用
ota 模块通过 WiFi 下载并烧写新的 .uf2 或 MicroPython 脚本。
