A set of input and output nodes for controlling General Purpose Input and Outputs (GPIOs) though the use of johnny-five I/O Plugins as well as running johnny-five scripts!

From inside your node-red directory:

npm install node-red-contrib-gpio

Node configuration

• 14 is the length of bytes to read (1 byte = 8 bits)
• i2c bytes is an array of bytes. You can't use inject node directly because data has to be inside an array.

msg.payload=[0x00]
return msg;

• i2c read and i2c write configure i2c connection. I2c and register are decimal values! parseInt(x, 10) function is used to read values.

node-red-contrib-gpio supports several johnny-five I/O classes:

Arduino is supported out of the box, but for other devices, you'll need to install their IO plugin.

For example to install the Raspberry Pi plugin:

npm install raspi-io

If you're using Arduino/Firmata, you can connect to a remote device via a raw tcp socket, or an MQTT connection.

For example, if you wanted to connect using tcp, in node-red you could specify an ip and port. On another machine with an Arduino plugged in you could run a server that relays a tcp socket to a serial port such as: tcpSerialRelay.js

If you wanted to connect an Arduino to an MQTT server you can use a script such as: bindSerialToMQTT.js. In node-red you can connect to the same MQTT server and subscribe to the topic the arduino is publishing on, while publishing to the topic that the arduino is subscribed to.