野路子學習esp32(十六) MQTT與ESP32-MicroPython @a.宏萬

MQTT與ESP32-MicroPython¶

在ESP32上安裝MQTT庫¶

首先，我們需要在ESP32上面安裝mqtt的庫。（MQTT客戶端在ESP32上面的實現）

首先確認ESP32-MicroPython已經連接上了熱點！！！, 通過REPL控制ESP32。

引入upip包管理器

>>> import upip >>> upip.install('micropython-umqtt.simple') Installing to: /lib/ Installing micropython-umqtt.simple 1.3.4 from https://files.pythonhosted.org/packages/bd/cf/697e3418b2f44222b3e848078b1e33ee76aedca9b6c2430ca1b1aec1ce1d/micropython-umqtt.simple-1.3.4.tar.gz 

這樣umqtt.simple這個包就安裝好了。

使用umqtt實現接收者¶

esp32/subscriber.py from umqtt.simple import MQTTClient import time SERVER = '192.168.43.16' CLIENT_ID = 'PYESPCAR_A0' TOPIC = b'pyespcar_basic_control' def mqtt_callback(topic, msg): print('topic: {}'.format(topic)) print('msg: {}'.format(msg)) client = MQTTClient(CLIENT_ID, SERVER) client.set_callback(mqtt_callback) client.connect() client.subscribe(TOPIC) while True: # 查看是否有數據傳入 # 有的話就執行 mqtt_callback client.check_msg() time.sleep(1) 

使用umqtt實現發送者¶

esp32/publisher.py from umqtt.simple import MQTTClient import time SERVER = '192.168.43.16' CLIENT_ID = 'PYESPCAR_A0' # 客戶端的ID TOPIC = b'pyespcar_basic_control' # TOPIC的ID client = MQTTClient(CLIENT_ID, SERVER) client.connect() while True: client.publish(TOPIC, 'helloworld') time.sleep(1) 

注意在Esp32里面TOPIC需要是bytes類型。

 

現在我們修改 boot.py

原來的 

from emp_wifi import Wifi
from emp_webrepl import WebREPL
from emp_utils import webrepl_pass
from emp_utils import post_ip


if __name__ == '__main__':
    Wifi.connect()
    try:
        post_ip(Wifi.ifconfig()[0][0])
    except ImportError:
        pass
    WebREPL.start(password=webrepl_pass())
    from emp_ide import *

新的

from emp_wifi import Wifi
from emp_webrepl import WebREPL
from emp_utils import webrepl_pass
from emp_utils import post_ip
import ubinascii
import machine
 
#mqtt 服務器相應的信息
mqtt_server = '*.*.*.*'
client_id = b'Q1'+ubinascii.hexlify(machine.unique_id()).upper()
mqtt_user = b'Q1'
mqtt_pwd = b''
topic_sub = client_id
topic_pub = b'Hongwans_EMQ'

if __name__ == '__main__':
    Wifi.connect()
    try:
        post_ip(Wifi.ifconfig()[0][0])
    except ImportError:
        pass
    WebREPL.start(password=webrepl_pass())
    from emp_ide import *

 

 main.py 可以這樣寫 

def connect_and_subscribe():
    global client_id, mqtt_server, topic_sub,mqtt_user,mqtt_pwd
    client = MQTTClient(client_id, mqtt_server,user=mqtt_user, password=mqtt_pwd, keepalive=60)
    client.set_callback(sub_cb)
    client.connect()
    client.subscribe(topic_sub)
    led.on()
    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()

 

#接收MQTT消息
def sub_cb(topic, msg):
    global iswhile
    msg = bytes.decode(msg)    
    print((topic, msg))  

 

try:
    #5小時重啟一次
    last_reset = time.time()
    reset_interval = 60 * 60 * 5
    #通知服務器我在
    last_message = 0
    message_interval = 1
    client = connect_and_subscribe()
    print('HwClient_SN:'+client_id.decode())
except OSError as e:
    restart_and_reconnect()

while True:
    try:
        client.check_msg()
        if (time.time() - last_reset) > reset_interval:
            restart_and_reconnect()
        if (time.time() - last_message) > message_interval:
            jsonData = '{"TheSender":"'+client_id.decode()+'","Receiver":"'+topic_pub.decode()+'","MessTpye":"string","Content":"ian"}';
            client.publish(topic_pub, jsonData)
            last_message = time.time()
    except OSError as e:
        restart_and_reconnect()

 

MQTT  服務器必須發送信息給一個主題。如果一直讀取沒有發送，MQTT會中斷。