MQTTDUINO

###An MQTT client for Arduinos connected to an esp8266 board

FEATURES

• Subscribe to topics
• Send messages
• Receive messages
• All qos levels
• Messages retain
• Authentication with username and password
• Last will and testament (in topic [mqtt id]/status)
• Auto reconnect on wifi drop or mqtt broker drop!
• Auto reset esp8266 on lock up!
• VERY easy to use and reliable, low memory footprint
• (TODO) SSL connection (can't do it for now due to memory constraint of nodemcu firmware)

USAGE

1) Connect esp8266 to Arduino

DISCLAIMER! I have NOT much experience in electronics, this is MY connection diagram and it's working well for me, but I don't know if it's 100% correct

2) Install nodemcu lua firmware on esp8266

I'm using 20150213 version, you can use any version from 20150212, hoping that future releases will not break compatibility with the script
You can find it there: https://github.com/nodemcu/nodemcu-firmware

3) Push mqttduino script on esp8266

Copy mqttduino.lua and init.lua on the esp8266
You can do it with LuaLoader: http://benlo.com/esp8266/
Don't forget to reboot the esp8266 after copying files

4) The Arduino sketch

The mqttduino.ino is a template for your sketch.
The template is self-explanatory

WARNING!

• I suggest to increate the Arduino serial buffer size in C:\Program Files (x86)\Arduino\hardware\arduino\avr\cores\arduino\HardwareSerial.h adding

#define SERIAL_TX_BUFFER_SIZE 100
#define SERIAL_RX_BUFFER_SIZE 100

under

...
#define SERIAL_TX_BUFFER_SIZE 64
#define SERIAL_RX_BUFFER_SIZE 64
#endif
#endif

- The script CAN'T receive messages or topics that contains the | character because it's used internally as a separator. Please don't use this character in topics or messages. - When the Arduino is subscribing to a topic or publishing a message, only one message will be queued. (Due to memory constraint)