MQTT-Node-RED顯示超音波測距數據+控制LED-micropython

MQTT-Node-RED顯示超音波測距數據+控制LED-mpython

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超音波測距(SC-SR04)實驗回顧-點我回顧

樹莓派上裝MQTT和Nord-RED回顧-點我回顧

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上述兩個都測試好之後就進入主程式部份

程式

from time import sleep

from machine import Pin, ADC, reset

from umqtttsimple import MQTTClient

import binascii, micropython, network, time, socket, machine


ssid = "---"

password = "---------"

mqtt_server = "192.168.--.--"

#將客戶端ID轉換為16進位,以便MQTT伺服端讀取

client_id = binascii.hexlify(machine.unique_id())

  
#和Nord-RED上的主題一致

client_adc = b'esp32/value'

client_led = b'esp32/output'

  
led = Pin(2, Pin.OUT)


lastTime = 0

currentTime = time.time()

  
#wifi連線

def connectWifi():

    global ssid, password

    wifi = network.WLAN(network.STA_IF)

    wifi.active(True)

    wifi.connect(ssid, password)

    while wifi.isconnected() == False:

            pass

    print("Connected successful!")

    print("IP: {}".format(wifi.ifconfig()))

#樹莓派上的mqtt回應訂閱

def sub_backCall(topic, msg):

    global led

    print((topic, msg))

    if msg == b"on":

        led.on()

    elif msg == b'off':

        led.off()

#連線MQTT,連線成功後訂閱主題

def connToMqtt():

    try:

        client = MQTTClient(client_id, mqtt_server)

        client.set_callback(sub_backCall)

        client.connect()

        client.subscribe(client_led)

        print("connect to %s"%mqtt_server)

        return client

    #如果無法連線重新連線

    except OSError as e:

        print("not to connected for MQTT server!")

        machine.reset()

#讀取ADC數值

def readVal():

    adc = ADC(Pin(36))

    adc.atten(ADC.ATTN_11DB)

    ADC.width(ADC.WIDTH_10BIT)

    while True:

        val =adc.read()

        return val

connectWifi()

client = connToMqtt()

while True:

    #檢查有無進來的訊息

    client.check_msg()

    value = readVal()

    print('val = {}'.format(value))

    #發送可調電阻值到MQTT

    client.publish(client_adc, str(value))

    sleep(0.05)

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Nord-RED布署

紫色區塊的主題要和程式一致

client_adc = b'esp32/value'

client_led = b'esp32/output'

開關Payload要和程式接收到的msg一致

#樹莓派上的mqtt回應訂閱

def sub_backCall(topic, msg):

    global led

    print((topic, msg))

    if msg == b"on":

        led.on()

    elif msg == b'off':

 led.off() 

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