MQTT Application

Table of Contents
Initialisation
Changing Settings
Changing settings
Getting started
- Set up
- Topics
- Colors

Initialisation

The MQTT application should be initialised in the main function:

mqtt_application_init();

In case a check for success is wanted, the function will return a '1' on failure and a '0' on success.

Changing Settings

Server Settings

Depending on how the MQTT broker is set up on the pc some settings might need to be changed in the mqtt_application.c file. Make sure you change the corresponding defines to how you have set everything up:

#define SERVER_IP4_A 192
#define SERVER_IP4_B 168
#define SERVER_IP4_C 69
#define SERVER_IP4_D 11
#define SERVER_PORT 1883

Publish Settings

In case you want to change the QOS and retain attributes of the pulbish done by the application, change the corresponding defines:

#define PUBLISH_QOS 2
#define PUBLISH_RETAIN 1

Text and image position

If you want to display the text and images on a different location you can change the following defines(the starting point is the same for both text and images):

#define PRINT_XPOS 50
#define PRINT_YPOS 50

Getting started

In order to use this application you are going to need an MQTT broker: use this version: mosquitto 1.16.1a: https://mosquitto.org/files/binary/win64/mosquitto-1.6.12a-install-windows-x64.exe

A publisher/subscriber is also required to have: recommended are: https://mqttx.app/ or https://github.com/eclipse/paho.mqtt-spy/wiki/Downloads

Setting up

Before testing the application make sure to run the mosquitto broker before starting and connecting the microcontroller.

Topics

The used topics are:

getImageList Upon start up a list of available images will get published here.
getGifList Upon start up a list of available gifs will get published here.
input/setText Text published here will be displayed on the LCD.
input/setImage Publish the correct name + extention for the image/gif you want to display here.
input/setColor Publish the color you want the backgroundcolor to be here. This will take effect after changing the text or image/gif.
input/setTextColor Publish the color you want the text to be here.

Colors

Colors should be published using the same format as listed below. Available colors are: "blue, green, red, cyan, magenta, yellow, light blue, light green, light red, light cyan, light magenta, light yellow, dark blue, dark green, dark red, dark cyan, dark magenta, dark yellow, white, light gray, gray, dark gray, black, brown, orange, transparent"

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