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Questions tagged [mqtt]

For questions concerning the MQTT messaging protocol, a lightweight TCP/IP-based system for machine-to-machine communication.

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2 votes
1 answer
397 views

Real-time web-app for IOT devices

Goal I'm currently building a web application to control multiple IOT devices over the cellular network. Given the nature of the devices (working off battery power and operating in constrained network ...
3 votes
2 answers
177 views

How can I make a topic/action to be allowed only to authorized users?

This is the scenario: I have a machine connected to a MQTT AWS-IoT Core broker. This machine is authorized with the AWS certificates to publish in the topic P/serialnb/deleterecords/record_id. This ...
2 votes
1 answer
187 views

Eclipse Mosquitto Dynamic Security Plugin

One question I can't seem to find any docs about. I have made a PHP API that uses the Dynamic Security Plugin. Is there any way I can map the pub with the response in the sub topic? As of now it ...
1 vote
2 answers
132 views

MQTT not connecting to local broker

I am really new to IoT and MQTT. For my project I want ESP32 to send data to node-red as a part of visualization requirement. I am running a broker (mosquitto) locally on my PC (Windows 11), I ...
0 votes
1 answer
53 views

Temperature Sensor IoT device that support cloud integration

I am looking for an IoT temperature sensor that does the following: Able to Communicate with cloud platform (aws, azure etc) Does not require a lot of programming. The device should be preconfigured. ...
5 votes
1 answer
1k views

Connect an esp32 with AWS MQTT with SIM800L

I am are trying to use a sim800L module to connect an esp32 running Arduino to AWS MQTT. I need to connect and publish and subscribe to topics. I am doing this successfully via WiFi. Not via the ...
2 votes
2 answers
2k views

Publish MQTT message via HTTP GET

I need to make a simple proof of concept, having an Arduino or ESP32 with a couple of LEDs than can be turned on/off via browser. There are a lot of examples about having a small server in the Arduino ...
8 votes
2 answers
4k views

MQTT multiple topics vs. bigger payload

I am wondering about best practices of topic naming and payload design of mqtt messages. Is it better to have multiple and long topic names instead and a bigger payload or short topic name with bigger ...
1 vote
1 answer
717 views

Matter node behavior in Matter protocol

What is the difference between MQTT and Matter protocol? Can I send Matter message between two different networks if Matter devices using link-local address?
4 votes
1 answer
507 views

C# based MQTT other than MQTTnet?

I was looking for a C# based MQTT broker which has full open library or api so that we can call those functions in our code to get messages and other relevant data such as list of connections, topics ...
1 vote
0 answers
25 views

Sonoff Tasmota sensor has hard time to connect to MQTT broker on a specific LAN

I have an old Sonoff TH16 (like this one) flashed with the Tasmota firmware to use it via MQTT. I have a mosquitto broker on an external server. It ran fine for several months inside my friend's LAN ...
1 vote
0 answers
111 views

Malformed Packet on Mosquitto

I am trying to connect to my mosquitto broker on esp32 with GSM using pubsubclient but sometimes it disconnects to broker with detail malformed packet. 2023-08-30T13:43:14: Client client_id ...
10 votes
2 answers
1k views

SIM5320 MQTT TCP connection closing unexpectedly after time

I have been working on an MQTT protocol using the SIM5320. I am familiar with the AT command documentation, and have a working implementation with an Arduino. I open a network socket with AT+NETOPEN ...
6 votes
2 answers
5k views

MQTT subscribing is not working

I am working to connect my server to the clients via an MQTT broker. The MQTT client gets connected. But after publishing a message, the subscribe code receives a connection acknowledgment. The ...
2 votes
0 answers
41 views

Smart Lock - nRF52840, Thread, Mqtt or Nats Questions

I am designing a battery operated smart lock with pin pad and cloud api and really trying to understand how I can make this work. IOT Smart Lock Device Requirments: 4x aa batteries should last ...
5 votes
1 answer
111 views

Any real-world HomeWSN deployments?

I searched for "MQTT Rules Engine", and came across the HomeWSN project. It looks like it's almost trying to be a home automation system based on MQTT messaging, which could be very useful. Has ...
3 votes
4 answers
37k views

Can't connect to Mosquitto broker with local IP address

I have a Mosquitto broker running on my Windows machine. I can connect to this on the same machine using an MQTT client such as MQTTX when I specify localhost as the address. However, I want other ...
3 votes
1 answer
703 views

How does the MQTT server output a single raw file from multiple client publications?

I'm trying my first IoT project whereby I want to: have an electret microphone capture audio have an ESP8266 NodeMCU 12-E board submit captured audio to a remote server have a remote server receive ...
2 votes
1 answer
110 views

extracting MQTT messages

I'm working on my first MQTT data collection project, and I need to write all the messages into one text file for later analysis. I do a little embedded programming in C, but I haven't written ...
1 vote
1 answer
114 views

OPC UA vs MQTT for internal interoperability

I am working on a project which will require networking with multiple IoT devices and sensors (scales, temperature sensors, actuated switches, etc.). I am familiar with the MQTT architecture, while I ...
2 votes
0 answers
27 views

ModbusRTU-MQTT Gateway Hardware

I am using currently a ModbusRTU-MQTT Gateway (HD67933-4-B2) to access a AC climatisation Device from Toshiba. A Intesis AC-Interface Device is converting the proprietary Toshiba Bus from the AC to ...
1 vote
2 answers
2k views

mosquitto_sub and grep to trigger command/action

I can use mosquitto_sub to subscribe to broker for a specific topic, say test_topic, mosquitto_sub -h MOSQUITTO_BROKER_HOSTNAME -t test_topic I can also pipe grep for a specific keyword, say ...
1 vote
1 answer
253 views

How do I control a device that works with Z-Wave JS UI via a published MQTT message?

I have a setup where I am running a simple mosquito server for MQTT. I then run the Z-Wave JS ui project to interact with my zwave devices. This works great and I see the messages showing up in MQTT ...
5 votes
1 answer
2k views

SSL/TLS connection to Mosquitto broker from Android app

I have configured the mosquitto mqtt broker on a raspberry pi via this link SSL/TLS Client Certs to Secure MQTT I have the ca.crt,client.crt and client.key. How do I use them in android? It would be ...
3 votes
1 answer
839 views

How to speed up first Mosquitto message?

When sending MQTT messages, first message arrives within 2 seconds and subsequent messages sent within less than 20 secs from first message, arrive in about 0.5 second. I would like to speed up those “...
5 votes
2 answers
3k views

How to extract values of multiple topics in onMessageArrived(message) function of Paho MQTT JavaScript API?

I have created a Publisher Script using Paho MQTT JavaScript API which publishes values to two topics MyHome/Temp and MyHome/Hum. The script is running successfully and publishing data to CloudMQTT ...
0 votes
0 answers
20 views

Why xargs cannnot receive input parameters through pipe?

Ubuntu 20.04 LTS Shell 1. mosquitto_sub -h 192.168.1.3 -t "application/2/device/df9cde4119c814ef/rx" -v application/2/device/df9cde4119c814ef/rx {"applicationID":"2",&...
1 vote
1 answer
799 views

tasmota on ESP8266 is not connecting to cloud mqtt server

I am trying to connect ESP8266 using tasmota, to a cloud mqtt broker and getting message MQT: Connect failed to broker.hivemq.com:1883, rc -2. Retry in 10 sec Any ideas?
2 votes
0 answers
360 views

Paho MQTT Client - on_message callback never happens

I have a Mosquitto MQTT broker (mosquitto version 2.0.11) running on a Raspberry Pi. It is publishing regular messages on a specific topic, which can be seen by running $ mosquitto_sub -h 192.168.27....
1 vote
1 answer
99 views

How do I access my Matter devices when I’m not at home?

How do device developers and major platform providers in the world such as Google Home, Apple, Tuya, and Aqara do to control Matter devices remotely??? Do they still use traditional IoT protocols like ...
2 votes
0 answers
85 views

What are the best practises AWS IoT thing registration process?

What are the best practises AWS IoT thing registration process? How can the process of making devices available to the users be streamlined? I need to know how can this be done in a viable way. ...
2 votes
2 answers
129 views

compute power for MQTT vs HTTP POST in cloud

Trying to get an understanding of the cloud side compute power comparison (and cost) for say 10,000 devices sending data to the cloud using HTTPS Vs MQTT. My co-worker says keeping 10k MQTT ...
14 votes
4 answers
3k views

Is it a bad practice to keep certificates on external memory?

We're working on AWS-IoT using an STM32 microcontroller. Till today, we were writing the certificates to the flash and locking the flash from external reading. As the application code increases, we'...
1 vote
2 answers
4k views

How to send data to ThingsBoard using MQTT in python?

I want to send data to ThingsBoard and display it in widget On dashboard. By Following this tutorial I have: Created Device on ThingsBoard by logging into Tenant Administrator. Device Description: ...
0 votes
1 answer
208 views

Mqtt in production

I am using Mqtt to build a project. I am wanting to move my whole work to prod ready. My hardware is ESP-07 and custom PCB design the broker is mosquitto the app (Nodejs,react native) I implemented ...
0 votes
1 answer
55 views

MQTT Client: Listeners Exceeded Warning

I'm a newbie building an IOT system comprised of two clients, the first client (Client A) will be a Subscriber and the second client (Client B) will be a Publisher. For the Broker, I intend to use ...
2 votes
0 answers
281 views

Vernemq loses all messages after pod restart, even with persistent storage

We're running a cluster with 2 VerneMq brokers. Everything works fine if we start one broker at one time, but as soon as we need to re-start both the brokers, all the retained messages are lost. To ...
1 vote
1 answer
150 views

Is there a way to be sure that the message is received by the subscriber in MQTT

As I understand, MQTT QoS levels are applicable on the connection between Publisher and Broker or Broker and Subscriber. QoS levels are nothing to do with the connection between Publisher and ...
1 vote
2 answers
732 views

Make connection in the background & closed app using MQTT

What is the proper way to show notifications of the message's received from mqtt when app is running in the background or when app is closed using react native. So far I have achieved to show ...
2 votes
1 answer
903 views

Connecting cellular module SIM7070G to AWS MQTT

I have troubles connecting SIM7070G (SIM7000 family) to AWS over built-in MQTT using AWS certificates. I've succeeded previously using the module only as a cellular gateway, but running FreeRTOS+...
4 votes
3 answers
4k views

MQTT - keepAlive using Arduino

I'm using MQTT broker for my IOT devicess, mostly ESP8266 ( some are NodeMCU, some Wemos mini, and some are Sonoff) , running an Arduino code, some time ( about a year ). MQTT broker is running on a ...
0 votes
1 answer
2k views

How to handle the connection in MQTT using Paho

I've managed to connect to my Mosquitto broker of Paho MQTT JS client. However, the client disconnects inmediately after completing the connection. Before it worked now I'm testing it doesn't work. ...
10 votes
7 answers
21k views

Can I use an ESP8266 as an MQTT broker?

I am making a home automation project based on star topology. What I am trying to achieve is that one of the nodemcu/ESP8266 acts as a server which is accessible for the outside world and other ...
2 votes
1 answer
303 views

LoPy4 MQTT Example does not Work

I have two LoPy4 Dev boards. I am using this tutorial in order to (successfully) communicate with the two boards. After receiving data in LoRa communication I am trying to also publish this data in an ...
0 votes
1 answer
1k views

Connect PHP WebServer as a MQTT subscriber

I would like some advices and help concerning a IoT stack. This is the stack I have imagined: Arduino, the IoT device Broker, doesn't matter for now, I will use a free public broker for testing. A ...
0 votes
0 answers
140 views

MQTT TLS by Node-RED

I had a problem when sending request using MQTT through Node-RED. I actually have a LorAWAN gateway that is connected to TTN Cloud and Node-red was deployed in the gateway as an additional application....
9 votes
1 answer
2k views

What happens if Mosquitto runs out of memory to store QoS 1/2 messages?

In MQTT, messages with QoS 1 or 2 must be delivered at least once (QoS 2 messages must be delivered exactly once). If the client is not connected, the broker must store the message until the client is ...
4 votes
1 answer
5k views

Mosquitto broker service not starting on Windows

I installed mosquitto for Windows, and ran the following command from command prompt as administrator: net start mosquitto I get the following message: The Mosquitto Broker service is starting. The ...
0 votes
2 answers
237 views

Determine state before publish

I have a mosquitto MQTT broker on a Raspberry Pi. I have some topics from a client in this format SolutionCommand/state as an array 110001. In other hand I can invoke some publish topics like ...
0 votes
0 answers
2k views

Send custom commands with zigbee2mqtt

Is it possible to send custom commands with zigbee2mqtt? I have found that I can send commands with Mosquitto, but they don't seem to be transferred directly. I am trying to send the commands to a ...

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