[作品提交] 【得捷电子Follow me第3期】任务6-2：温湿度数据记录仪

HonestQiao 2023-12-9 23:04 楼主

这篇帖子，在之前【得捷电子Follow me第3期】任务5：使用外部传感器：温湿度传感器的基础上，加上MQTT，使得温湿度信息通过MQTT发布到服务端，然后，再使用手机端App接受，并进行呈现。

一、mqtt服务器

可以自己搭建mqtt服务器：https://www.emqx.io/zh/downloads?os=Ubuntu ；搭建好了以后，在管理界面，添加一个用户，以便连接。

当然，也可以使用EMQX官方提供的公共服务器进行测试：https://www.emqx.com/zh/mqtt/public-mqtt5-broker

二、micropython连接MQTT服务

在Seeed Studio XIAO ESP32C3的micropython中连接MQTT服务，可以使用umqttsimple库，下载地址为：https://raw.githubusercontent.com/RuiSantosdotme/ESP-MicroPython/master/code/MQTT/umqttsimple.py

连接到mqtt并发送信息，可以使用如下的代码进行测试：

import time
from umqttsimple import MQTTClient
import ubinascii
import machine
import micropython
import network
import esp
esp.osdebug(None)
import gc
gc.collect()

ssid = 'OpenBSD'
password = '********'
mqtt_server = '192.168.1.15'
mqtt_user = 'user_esp32c3'
mqtt_pass = '123456'

client_id = ubinascii.hexlify(machine.unique_id())
topic_sub = b'/device/cmd'
topic_pub = b'/device/report'

last_message = 0
message_interval = 5
counter = 0

station = network.WLAN(network.STA_IF)

station.active(True)
station.connect(ssid, password)

while station.isconnected() == False:
  pass

print('Connection successful')
print(station.ifconfig())

def sub_cb(topic, msg):
  print((topic, msg))

def connect_and_subscribe():
  global client_id, mqtt_server, mqtt_user, mqtt_pass, topic_sub
  client = MQTTClient(client_id, mqtt_server, user=mqtt_user, password=mqtt_pass)
  client.set_callback(sub_cb)
  client.connect()
  client.subscribe(topic_sub)
  print('Connected to %s MQTT broker, subscribed to %s topic' % (mqtt_server, topic_sub))
  return client

def restart_and_reconnect():
  print('Failed to connect to MQTT broker. Reconnecting...')
  time.sleep(10)
  machine.reset()

try:
  client = connect_and_subscribe()
except OSError as e:
  restart_and_reconnect()

while True:
  try:
    new_message = client.check_msg()
    if new_message != 'None':
      client.publish(topic_pub, b'received')
    time.sleep(1)
  except OSError as e:
    restart_and_reconnect()

注意，上述代码中，mqtt服务的设置请修改为对应的：

mqtt_server = '192.168.1.15'
mqtt_user = 'user_esp32c3'
mqtt_pass = '123456'

连接mqtt服务成功后，使用下面的调用，即可发布消息：

client.publish(topic_pub, b'需要发布的消息')

在EMQX的管理后台，使用WebSocket工具，就可以查看发布的消息，已经发送消息给开发板：

三、完成温湿度信息的发布

完整的代码，在【得捷电子Follow me第3期】任务5：使用外部传感器：温湿度传感器的基础上，结合上面的MQTT部分的代码，具体如下：

import utime
from machine import Pin, SoftI2C

import ahtx0

from color_setup import ssd
from color_setup import i2c

from gui.core.nanogui import refresh
from gui.core.writer import CWriter
from gui.widgets.textbox import Textbox
from gui.widgets.label import Label
from gui.core.colors import *

# 字体调用
import gui.fonts.arial10 as arial10

import machine
import network
from umqttsimple import MQTTClient
import ubinascii
import gc
gc.collect()

mqtt_server = '192.168.1.15'
mqtt_user = 'user_esp32c3'
mqtt_pass = '123456'

client_id = ubinascii.hexlify(machine.unique_id())
topic_sub = b'/device/cmd'
topic_pub = b'/device/report'

last_message = 0
message_interval = 5
counter = 0

# 无线连接设置
wifi_ssid = "OpenBSD"
wifi_password = "********"

def sub_cb(topic, msg):
  print((topic, msg))

def connect_and_subscribe():
  global client_id, mqtt_server, mqtt_user, mqtt_pass, topic_sub
  client = MQTTClient(client_id, mqtt_server, user=mqtt_user, password=mqtt_pass)
  client.set_callback(sub_cb)
  client.connect()
  client.subscribe(topic_sub)
  print('Connected to %s MQTT broker, subscribed to %s topic' % (mqtt_server, topic_sub))
  return client

def restart_and_reconnect():
  print('Failed to connect to MQTT broker. Reconnecting...')
  time.sleep(10)
  machine.reset()

# 清屏
refresh(ssd, True)

# 显示输出
CWriter.set_textpos(ssd, 0, 0)
wri = CWriter(ssd, arial10, verbose=False)
wri.set_clip(True, True, False)

# 联网处理
def scan_and_connect():
    station = network.WLAN(network.STA_IF)
    station.active(True)
    
    if not station.isconnected():
        print("Scanning for WiFi networks, please wait...")
        for ssid, bssid, channel, RSSI, authmode, hidden in station.scan():
            print("* {:s}".format(ssid))
            print("   - Channel: {}".format(channel))
            print("   - RSSI: {}".format(RSSI))
            print("   - BSSID: {:02x}:{:02x}:{:02x}:{:02x}:{:02x}:{:02x}".format(*bssid))
            print()

        while not station.isconnected():
            print("Connecting...")
            station.connect(wifi_ssid, wifi_password)
            utime.sleep(10)

    print("Connected!")
    print("My IP Address:", station.ifconfig()[0])


# 联网
ssd.fill(0)
refresh(ssd)
Label(wri, 5, 0, "WiFi Connect...")
refresh(ssd)

scan_and_connect()

Label(wri, 5, 0, "WiFi Connect OK.")
refresh(ssd)

utime.sleep(2)

try:
    Label(wri, 5, 0, "MQTT Connect...")
    refresh(ssd)
    client = connect_and_subscribe()
    Label(wri, 5, 0, "MQTT Connect OK.")
    refresh(ssd)
    utime.sleep(2)
except OSError as e:
  restart_and_reconnect()

ssd.fill(0)
refresh(ssd)

# 显示日期
txt = Label(wri, 0, 0, "Environmental information")

pargs = (13, 2, 124, 4)  # Row, Col, Width, nlines

tb = Textbox(wri, *pargs, clip=False)

sensor = ahtx0.AHT10(i2c)

last_time = 0
cron_time = 10 # 定时间隔时间

while True:
    if last_time == 0 or utime.time() - last_time == cron_time:
        last_time = utime.time()
    else:
        utime.sleep(1)
        continue

    print("\nlast_time: %d" % last_time)
    print("Temperature: %0.2f C" % sensor.temperature)
    print("Humidity: %0.2f %%" % sensor.relative_humidity)

    
    tb.clear()
    tb.append("\n", ntrim = 100)
    tb.append(" Temperature: %0.2f C" % sensor.temperature, ntrim = 100)
    tb.append("  Humidity:       %0.2f %%" % sensor.relative_humidity, ntrim = 100)
    refresh(ssd)
    
    client.publish(b"%s/temp" % topic_pub, b'{"value":%0.1f}' % sensor.temperature)
    client.publish(b"%s/hum" % topic_pub, b'{"value":%0.1f}' % sensor.relative_humidity)

    utime.sleep(5)

上面代码的核心在于循环部分，原来是显示，现在多了：

    client.publish(b"%s/temp" % topic_pub, b'{"value":%0.1f}' % sensor.temperature)
    client.publish(b"%s/hum" % topic_pub, b'{"value":%0.1f}' % sensor.relative_humidity)

这两行代码，负责发布温度信息和湿度信息到MQTT服务，需要注意发布的topic：