mcinnes01/mcp23s17_mqtt

An arduino sketch for controlling an MCP23S17 GPIO expander using JSON messages with MQTT

MCP23S17_Mqtt

An arduino sketch for controlling an MCP23S17 GPIO expander using JSON messages with MQTT.

The idea of this sketch is to provide a simple way of controlling many pins on arduino remotely using simple Json commands.

This uses the following libraries:

Majenko MCP23S17: https://github.com/MajenkoLibraries/MCP23S17 aJson: https://github.com/interactive-matter/aJson PubSubClient: https://github.com/knolleary/pubsubclient

Commands

Currently there are only two commands implemented, ON and OFF. You can send the pin and pin state in a JSON message as follows. I am using two MCP23S17s and so to make things simpler I can address the pin 0-31 with 0-15 being on bank1 and 16-31 bank2.

Turn pin 4 ON

{ "command": { "lightmode": "ON", "pinnumber": 4 } }

Turn pin 4 OFF

{ "command": { "lightmode": "OFF", "pinnumber": 4 } }