Questions tagged [mqtt]
MQTT (Message Queuing Telemetry Transport) is a machine-to-machine (M2M)/"Internet of Things" connectivity protocol. The MQTT protocol enables a publish/subscribe messaging model in an extremely lightweight way. It is useful for connections with remote locations where a small code footprint is required and/or network bandwidth is at a premium.
89 questions
1
vote
0
answers
47
views
Secure upload to ThingSpeak with Arduino MKR GSM 1400 using GSMSSLCLient
I have an issue when trying to upload sensor data to ThingSpeak using the GSMSSLClient with the Arduino MKR GSM 1400 over MQTT. Each time I attempt to establish an MQTT connection, the state is always ...
5
votes
1
answer
239
views
MQTT connection fails when using String objects
On my ESP32 I am trying to connect to my HomeAssistant server using ArduinoHA library.
I can easily connect when hard-coding the credentials: mqtt.begin("server", "username", "...
- 201
0
votes
1
answer
75
views
How to make MQTT and ArduinoModbus libraries working on the same Ethernet port?
I have a SAMD51P20 based Arduino PLC with WIZnet W5500 based Ethernet shield. I'm using these libraries:
#include <Ethernet.h>
#include <MQTT.h>
#include <ArduinoModbus.h>
MQTT and ...
- 209
0
votes
1
answer
1k
views
How to check if the MQTT connection is still active?
I am wondering if there is a way to check and see if the MQTT connection is still active.
The reason for this is that I am having trouble with the connection dropping after a short while and not ...
- 21
1
vote
1
answer
258
views
PubSubClient hanging on ESP32C3
I may have done some things incorrectly here, but this I what I have for publishing image that I read from serial camera to the MQTT broker:
void capturePicture() {
if (!cam.takePicture())
...
- 121
1
vote
0
answers
108
views
Arduino secure mqtt example not subscribing to topic
I am wrestling with the below example.
I have a RasPi on the network running Mosquito with username and password credentials setup and I know this is working.
If I load the below example, I can ...
- 11
1
vote
1
answer
92
views
Weird behaviour with BearSSL on GPIO ESP8266
I use GPIO 5 to trigger a relay. My code also connects with a secure MQTT connection for which I have to use the BearSSL certificate definitions.
Without the BearSSL certificates, when the ESP ...
1
vote
0
answers
231
views
How to connect to MQTT broker from NodeMCU with SSL?
I cannot connect to a MQTT broker from a NodeMCU, when using SSL.
This is the error message:
Attempting MQTT connection...failed, rc=-4 try again in 5 seconds.
When connecting to the same broker via ...
1
vote
1
answer
1k
views
Problem with using PubSubClient, the "callback" function doesn't seem to work correctly
I have a program that communicate between a esp8266 and a atmega328 using Serial, the esp8266 will connect to a MQTT server running on local network, and publish/subscribe to some topics. In the ...
- 11
2
votes
0
answers
698
views
MQTT on ESP8266 cannot connect if using Last Will service
Issue (short) description
An ESP8266 using PubSubClient fails to establish connection to MQTT broker (mosquitto) if requesting Last Will Testament (LWT) on connection, though it is able to connect ...
- 145
1
vote
0
answers
122
views
Empty message parse using ArduinoJSON from aedes MQTT server
I'm using aedes as my custom MQTT broker and PubSubClient at the ESP32 side, together with the ArduinoJSON package.
My server test code:
import Aedes from "aedes";
import net from "net&...
- 111
2
votes
0
answers
228
views
AsyncMqttclient publish affects accelerometer readings
Using M5StickC ESP32 with built-in MPU6886 accelerometer to read vibrations. In the loop() section the code gets 10 readings per second and if the readings exceed a threshold, it starts publishing the ...
- 21
3
votes
1
answer
1k
views
how to transfer json to string?
I am getting a json object from aws iot MQTT. Assuming that json from aws is {status:opened}.
Here is my code.
#include <ArduinoJson.h>
void messageHandler(char *topic, byte *payload, unsigned ...
- 53
1
vote
2
answers
1k
views
Arduino does not connect to MQTT local broker
I have an Arduino Mega with Ethernet connected to a router by cable. Also I have a PC connected to the router (by Wifi) where also the local MQTT broker is installed (mosquitto). Althought the Arduino ...
- 141
0
votes
1
answer
782
views
ESP32- Sporadic slow receive of MQTT messages
Problem description: Every ~20+ published messages (using terminal), MCU receives that message in a very noticeable delay (mostly ~10 sec, few time it got up to 1 min). Upon receive (printed in Serial ...
- 1,049