在 Raspberry Pi 上使用 MQTT 将传感器数据发布到 Thingspeak 时出错

Question

我已将土壤湿度传感器模块和 LDR 连接到 ADS1115 ADC（它又连接到我的 R Pi）。我正在使用 Python 2.7。 ADC 工作正常，它分别从通道 0 和通道 1 打印土壤湿度模块和 LDR 的值。我有以下代码使用以下指南将数据从土壤水分模块发送到 Thingspeak： https://www.mathworks.com/help/thingspeak/use-raspberry-pi-board-that-runs-python-websockets-to-publish-to-a-channel.html

https://github.com/adafruit/Adafruit_Python_ADS1x15

import time
import sys
from time import sleep
import paho.mqtt.publish as publish
import Adafruit_ADS1x15

#GPIO.setmode(GPIO.BOARD)

#Start of user config

channelID= "377509"
apiKey= "<APIKEY>"


#MQTT Connection Methods

useUnsecuredTCP= True

useUnsecuredWebsockets= False

useSSLWebsockets= False

mqttHost= "mqtt.thingspeak.com"

# You can use any Username.
mqttUsername = "SoilHumidityRpiDemo"

# Your MQTT API Key from Account > My Profile.
mqttAPIKey ="<APIKEY>"

if useUnsecuredWebsockets:
 tTransport= "websockets"
 tPort= 80

#Create topic string
topic= "channels/" + channelID + "/publish/" + apiKey


# Create an ADS1115 ADC (16-bit) instance.
adc = Adafruit_ADS1x15.ADS1115()

GAIN = 1

print('Reading ADS1x15 values, press Ctrl-C to quit...')

while True:
    m = adc.read_adc(0, gain=GAIN)
    print('Moisture Level:{0:>6}'.format(m))
    time.sleep(1)
    tPayload= "field1=%s" % m
    try:
      publish.single(topic, payload=tPayload, hostname=mqttHost, port=tPort, transport= tTransport,auth={'username':mqttUsername,'password':mqttAPIKey})
    except KeyboardInterrupt:
        break
    except:
        print ("There was an error publishing the data")

当我执行它时，出现错误消息"There was an error publishing the data"。然而，当我只是运行一个脚本来从终端上的 ADC 打印土壤湿度值（没有通过 MQTT 将数据发送到 Thingspeak 的代码）时，该脚本运行良好。

Answer 1

问题是因为 tPort 和 tTransport 仅在 useUnsecuredWebsockets 为 True

时才定义

由于 useUnsecuredWebsockets 设置为 False 之前的几行，这将永远不会发生。

您可以将 useUnsecuredWebsockets 更改为 True 或在 if 语句中添加 else 子句以设置默认值。

if useUnsecuredWebsockets:
 tTransport= "websockets"
 tPort= 80
else:
 tTransport = "tcp"
 tPort= 1883

在 Raspberry Pi 上使用 MQTT 将传感器数据发布到 Thingspeak 时出错

Error publishing sensor data to Thingspeak using MQTT on Raspberry Pi

python

mqtt

raspberry-pi

paho