Publish via Paho-MQTT publish.single but data is not arriving?
Hoang Bach
on 19 Jun 2022
Latest activity Edit by Christopher Stapels
on 16 Apr 2024
Hey, so I have a simple air quality measurement IoT system but the values are not arriving in my ThingSpeak channel. I use basic tutorials for it and tried some kind of variation but the code is so simple, I don't see any problem code-wise. Maybe someone here can help me?
I am working with a Raspberry Pi 3 and the following code for a SDS011 sensor:
import time
from datetime import datetime
import paho.mqtt.publish as publish
import paho.mqtt.client as mqtt
import psutil
from sds011 import *
import aqi
sensor = SDS011("/dev/ttyUSB0", use_query_mode=True)
def get_data(n=3):
sensor.sleep(sleep=False)
pmt_2_5 = 0
pmt_10 = 0
time.sleep(10)
for i in range (n):
x = sensor.query()
pmt_2_5 = pmt_2_5 + x[0]
pmt_10 = pmt_10 + x[1]
time.sleep(2)
pmt_2_5 = round(pmt_2_5/n, 1)
pmt_10 = round(pmt_10/n, 1)
sensor.sleep(sleep=True)
time.sleep(2)
return pmt_2_5, pmt_10
def conv_aqi(pmt_2_5, pmt_10):
aqi_2_5 = aqi.to_iaqi(aqi.POLLUTANT_PM25, str(pmt_2_5))
aqi_10 = aqi.to_iaqi(aqi.POLLUTANT_PM10, str(pmt_10))
return aqi_2_5, aqi_10
def save_log():
with open("/YOUR PATH/air_quality.csv", "a") as log:
dt = datetime.now()
log.write("{},{},{},{},{}\n".format(dt, pmt_2_5, aqi_2_5, pmt_10, aqi_10))
log.close()
channelID = "YOUR CHANNEL ID"
apiKey = "YOUR WRITE KEY"
clientID = "YOUR CLIENT ID"
tUsername = "YOUR USERNAME"
tPassword = "YOUR PASSWORD"
topic = "channels/" + channelID + "/publish/" + apiKey
mqttHost = "mqtt3.thingspeak.com"
tTransport = "tcp"
tPort = 1883
tTLS = None
tProtocol = mqtt.MQTTv311
while True:
pmt_2_5, pmt_10 = get_data()
aqi_2_5, aqi_10 = conv_aqi(pmt_2_5, pmt_10)
print ("AQI2.5 =", aqi_2_5," AQI10 =", aqi_10)
tPayload = "field1=" + str(pmt_2_5)+ "&field2=" + str(aqi_2_5)+ "&field3=" + str(pmt_10)+ "&field4=" + str(aqi_10)
try:
publish.single(topic, payload=tPayload, hostname=mqttHost, port=tPort, client_id=clientID, auth={'username':tUsername, 'password':tPassword}, tls=tTLS, transport=tTransport, protocol=tProtocol)
print ("[INFO] Published data")
save_log()
time.sleep(60)
except Exception as e:
print ("[INFO] Failure in sending data")
print (e)
time.sleep(60)
6 Comments
Time Descending
So is this page in your documentation outdated then: https://se.mathworks.com/help/thingspeak/use-raspberry-pi-board-that-runs-python-websockets-to-publish-to-a-channel.html?
Is there any way to use paho_mqtt to publish data in ThingSpeak or is the only option to use MQTT X?
The code you reference should work. You can definitely still use paho, im pretty sure ive done it already on a pi. Just set up am MQTT device on the thingSpeak web UI, enable publishing from that device to your channel of interest, and copy the credentials to the pi. Can you tell us where it is failing for you?
Now I found it: one extra /. Had f"channels/{channel_ID}/publish/ instead of f"channels/{channel_ID}/publish
Damn, it was hard to find it. :P Thanks for help anyway!
Ive had that one before, sorry I didnt look close enough to see that. We appreciate you sharing the solution!
If its working, can you share an interesting plot from your monitor to inspire others who see this discussion?
The topic you are publishing to is incorrect. Take a look at the examples Christopher has linked to.
Have a look at the documentation for MQTT and the provided examples. You are using syntax from the old broker, which was replaced in July 2021 and deprecated in April. Here is the new publish syntax for publish.
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