node-red-contrib-i2c

node-red-contrib-i2c

This set of node-red nodes communicate with the Raspberry Pi I2C driver and uses the node-I2C package. Run the following command in the root directory of your Node-RED install, usually this is ~/.node-red.

This node now allows you configure the bus number of the i2c driver. For most Pi this is 1 for /dev/i2c-1, or 0 for /dev/i2c-0 for a older rev 1 Pi.

Install

Either use the Manage Palette option in the Node-RED Editor menu, or run the following command in your Node-RED user directory - typically ~/.node-red

npm install --unsafe-perm node-red-contrib-i2c

Usage

Provides three nodes - one to scan connected device, one to receive messages, and one to send.

Scan I2C

This will scan the I2C bus for connected devices. It has one input to trigger the scan process and 2 outputs:

• The first output gives a list of all found devices in msg.payload and will be triggered once.
• The second output will be triggered for every found device. The address will be in msg.payload

Input I2C

This node will request data from a given device. The address and command can both be set in the dialog screen or dynamically with msg.address and msg.command. This node outputs the result as a buffer in msg.payload and places the address in msg.address and command in msg.command.

Output I2C

This node will send a given String/array/buffer to a given device. The address and command can both be set in the dialog screen or dynamically with msg.address and msg.command. The payload can be set statically or dynamically (using msg.payload).

This payload can be a Buffer, Array, String or Integer. When you use integers the number of bytes to send is important and can be set between 0 and 31 bytes.

Since v0.5.0 - you can daisychain this node, the input msg is sent unchanged to the next node.

Important Note

This node is now using the I2C-bus package from @fivdi. It looks more robust and better for asyncrone processes like node-red. I would like to thank the maker for his work. You can vind his work on github: https://github.com/fivdi/i2c-bus

The pld set of nodes did use the work of Kelly's I2C package to work. And I would like to thank him for the work he did on that package. For more info check out his github account at: https://github.com/kelly/node-i2c