I2C

The I2C module provides access to I2C/SMBus devices via the Linux kernel driver.

Don’t forget to install the requirements

pip3 install -r requirements/i2c.txt

Attention

You must have the I2C Kernel module installed and configured for this module to work. This process will vary based on the board and operatering system you are using.

Permissions

A udev rule file is provided to simplify access permissions for I2C buses.

First add the i2c group if it does not exist and add the user running MQTTany to the i2c group:

sudo addgroup --system i2c
sudo usermod -aG i2c mqttany

Then install the udev rule and reboot:

sudo cp udev/98-i2c.rules /etc/udev/rules.d/
sudo reboot now

Devices

See the device pages below for details on each one and to see any additional options available.

MCP230xx

Paths

Device IDs are used as the nodes in this module, giving paths like {device-id}/{property-id}. The device pages give more detail on the properties they provide.

Path	Description
`i2c/polling-interval`	The polling interval will be published here with `retained = True` when the device is started.
`i2c/poll-all/set`	Sending any message (even blank) here will poll all configured devices to publish their current states.
`{device-id}/address`	Device address will be published here with `retained = True` when the device is started.

Configuration

Optional settings are commented out with default values shown.

i2c:

  #polling interval: 60

  device-id:
    #name: '{device_id}'
    device: ''
    #bus: 1
    address: 0x

Module Settings

Option

Description

polling interval

Interval in seconds to publish all device states.

Optional, default 60.

Device Definition

Device configuration section names must be unique throughout the config file as they are used as node IDs. Node IDs can only contain lowercase letters a-z, numbers 0-9, and hyphens -. The following settings are for device definitions:

Option	Description
`name`	Friendly name for the device Substitutions: `{device_id}` will be replaced with the device section name. `{address:02d}` will be replaced with the device’s address as a decimal number. `0x{address:02x}` will be replaced with the device’s address as a hexadecimal number. Optional, default `{device_id}`.
`device`	Device model, see Devices for available options.
`bus`	I2C bus ID or full path to bus Optional, default `1`.
`address`	7-bit hex address of the device (Ex. `0x20` or `32`)