Arduino Client for MQTT PlugPlay

This library provides a client for doing simple publish/subscribe messaging with MQTT PlugPlay.

This library is derived almost entirely from the great work done here: https://github.com/knolleary/pubsubclient

Examples

The library comes with a number of example sketches. See File > Examples > PlugPlayMQTT within the Arduino application.

Limitations

• It can only publish QoS 0 messages. It can subscribe at QoS 0 or QoS 1.
• The maximum message size, including header, is 128 bytes by default. This is configurable via MQTT_MAX_PACKET_SIZE in PubSubClient.h.
• The keepalive interval is set to 15 seconds by default. This is configurable via MQTT_KEEPALIVE in PubSubClient.h.
• The client uses MQTT 3.1.1 by default. It can be changed to use MQTT 3.1 by changing value of MQTT_VERSION in PubSubClient.h.

Compatible Hardware

The library uses the Arduino Ethernet Client api for interacting with the underlying network hardware. This means it Just Works with a growing number of boards and shields, including:

• Arduino Ethernet
• Arduino Ethernet Shield
• Arduino YUN – use the included YunClient in place of EthernetClient, and be sure to do a Bridge.begin() first
• Arduino WiFi Shield - if you want to send packets > 90 bytes with this shield, enable the MQTT_MAX_TRANSFER_SIZE define in PubSubClient.h.
• Sparkfun WiFly Shield – library
• TI CC3000 WiFi - library
• Intel Galileo/Edison
• ESP8266

The library cannot currently be used with hardware based on the ENC28J60 chip – such as the Nanode or the Nuelectronics Ethernet Shield. For those, there is an alternative library available.

Install

Clone (or download and unzip) the repository to ~/Documents/Arduino/libraries where ~/Documents/Arduino is your sketchbook directory.

> cd ~/Documents/Arduino
> mkdir libraries
> cd libraries
> git clone https://github.com/plugplayco/plugplay-arduino-mqtt PlugPlayMQTT

Usage

setAuth( const char* userKey, const char* boardId)

Set authentication to connect to PlugPlay

Arguments:

• userKey - user Key of your user account.
• boardId - board Id of board you want to publish/subcribe to.

boolean connectPlugPlay(const char* id)

Connect to PlugPlay with a MQTT client Id

Arguments:

• id - client Id (should be a random Id)

// Create a random client ID
String clientId = "ArduinoClient-";
clientId += String(random(0xffff), HEX);

client.connectPlugPlay(clientId.c_str());

char* createMsg(String dvName, float data0)

char* createMsg(String dvName, float data0, float data1)

char* createMsg(String dvName, float data0, float data1, float data2)

Create a message to publish

Arguments:

• dvName - device name
• data0 - first data
• data1 - second data
• data2 - third data

boolean subPlugPlay(const char* topic)

Subcribe a topic

boolean pubPlugPlay(const char* topic, const char* payload)

Publish a message to a topic. The message is created by createMsg(String dvName, float data0, float data1, float data2)

String getName(const char* payload)

Get device name from a received message

float getData(const char* payload, const char* type)

Get data from a received message

// Get the first data
client.getData((char*)payload,"data0");
// Get the second data
client.getData((char*)payload,"data1");
// Get the third data
client.getData((char*)payload,"data2");

Other functions

You can refer here: http://pubsubclient.knolleary.net

License

This code is released under the MIT License.