51 lines
2.0 KiB
Markdown
51 lines
2.0 KiB
Markdown
# Arduino Client for MQTT
|
||
|
||
This library provides a client for doing simple publish/subscribe messaging with
|
||
a server that supports MQTT.
|
||
|
||
## Examples
|
||
|
||
The library comes with a number of example sketches. See File > Examples > PubSubClient
|
||
within the Arduino application.
|
||
|
||
Full API documentation is available here: https://pubsubclient.knolleary.net
|
||
|
||
## Limitations
|
||
|
||
- It can only publish QoS 0 messages. It can subscribe at QoS 0 or QoS 1.
|
||
- The maximum message size, including header, is **256 bytes** by default. This
|
||
is configurable via `MQTT_MAX_PACKET_SIZE` in `PubSubClient.h` or can be changed
|
||
by calling `PubSubClient::setBufferSize(size)`.
|
||
- The keepalive interval is set to 15 seconds by default. This is configurable
|
||
via `MQTT_KEEPALIVE` in `PubSubClient.h` or can be changed by calling
|
||
`PubSubClient::setKeepAlive(keepAlive)`.
|
||
- 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](https://github.com/dpslwk/WiFly)
|
||
- TI CC3000 WiFi - [library](https://github.com/sparkfun/SFE_CC3000_Library)
|
||
- Intel Galileo/Edison
|
||
- ESP8266
|
||
- ESP32
|
||
|
||
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](https://github.com/njh/NanodeMQTT) available.
|
||
|
||
## License
|
||
|
||
This code is released under the MIT License.
|