Sending data to server using MQTT



  • Hello Team,

    Am using MQTT to send sensor data to server, i have included mqtt.py library and am running the attached code in the atom but getting the following error,
    Traceback (most recent call last):
    File "<stdin>", line 23, in <module>
    File "mqtt.py", line 56, in connect
    OSError: -1

    Kindly help with this where am doing wrong. Please reply as soon as possible.

    Thank You
    [0_1524203120867_sub.py](Uploading 100%)



  • @timh
    Ok, i have connected the fipy to our wifi network & it is connected successfully, and also checked the ip address address and ping fipy is working.



  • @nazz you need stablish that your fipy is actually connected to the Wifi network, has got a valid IP/netmask etc from your DHCP server. These are basic network tests you should perform before thinking about problem with high level libraries like MQTT. Once you have established you have a working network connection then start looking at your code.

    Another way of checking is trying to telnet or ftp to your FiPy from your PC.



  • @timh

    I did not understand clearly, ping fipy means , do i need to do
    ping 192.168.4.1 into my computer??



  • @nazz ok, but do you have a valid network connection. Can you ping the fipy for instance.



  • @timh

    Yes, right now am using my computer as broker and i have setup mosquitto in it which is listing on port 1883, below is the response
    [root@localhost /]# sudo netstat -tlnp | grep mosq
    tcp 0 0 0.0.0.0:1883 0.0.0.0:* LISTEN 7918/mosquitto
    tcp6 0 0 :::1883 :::* LISTEN 7918/mosquitto

    In code i have given my computer ip address, but also not working.



  • @nazz have you confirmed that you have a valid network connection, (for instance can resolve DNS names) and the MQTT broker you are connecting to is listening on port 1883. Some are listening on 8883 and require TLS.



  • @timh

    Thank you for your response, i dint get what does this line means " unless you are running a broker on the FiPy which I doubt" , means in case we are running subscriber code on fipy??

    And also in this line "MQTTClient("fipy", "localhost", port=1883)" , i have changed the localhost to respective ip address where i want to send the data, but still same error.

    Can you please help me where am going wrong.

    Thank You



  • At the moment your MQTT connection is attempting to connect to itself. MQTTClient("fipy", "localhost", port=1883) unless you are running a broker on the FiPy which I doubt, you need to have the name or IP address of the MQTT server you wish to connect to.



  • Hello,

    Sorry for posting again , this is the same issue , Am using MQTT to send sensor data to server, i have included mqtt.py library and am running the below code in the atom but getting the following error,

    Traceback (most recent call last):
    File "<stdin>", line 23, in <module>
    File "mqtt.py", line 56, in connect
    OSError: -1

    CODE:
    from network import WLAN
    from mqtt import MQTTClient
    import machine
    import time
    from pysense import Pysense
    from LTR329ALS01 import LTR329ALS01
    import os

    def settimeout(duration):
    pass

    wlan = WLAN(mode=WLAN.STA)
    wlan.antenna(WLAN.EXT_ANT)
    wlan.connect("ssid", auth=(WLAN.WPA2, "password"), timeout=5000)

    while not wlan.isconnected():
    machine.idle()

    print("Connected to Wifi\n")
    client = MQTTClient("fipy", "localhost", port=1883)
    client.settimeout = settimeout
    client.connect()

    while True:
    print("Sending ON")
    py = Pysense()
    lt = LTR329ALS01(py)
    print("Light (channel Blue lux, channel Red lux): " + str(lt.light()))
    client.publish("/lights", str(lt.light()))
    time.sleep(1)
    print("Battery voltage: " + str(py.read_battery_voltage()))
    print("Sending OFF")
    client.publish("/lights", str(py.read_battery_voltage()))
    time.sleep(1)
    client.disconnect()

    Kindly help with this where am doing wrong. Please reply as soon as possible.

    Thank You


 

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