OneWire

The OneWire module provides access to Dallas/Maxim OneWire devices using the w1 kernel module.

Attention

You need to have wire-1 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 wire-1 devices.

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

sudo addgroup --system wire
sudo usermod -aG wire mqttany

Then install the udev rule and reboot:

sudo cp udev/98-w1.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 for them.

• DS18x20

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
onewire/polling-interval	The polling interval will be published here with retained = True when the device is started.
onewire/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, default values are shown.

onewire:

  #bus: 'w1'
  #polling interval: 0
  #bus scan: false

  device-id:
    address: ''
    #name: '{device_id}'

  batch-id:
    address: ['', '']
    #name: '{device_id}'
    #name: [  ]    # can also provide a matching list of names
    #first index: 0

Module Settings

Option	Description
bus	OneWire bus interface, currently only w1 is supported. Optional, default w1.
polling interval	Interval in seconds to publish all pin states. Optional, default 60.
bus scan	Set to true to have the OneWire module scan the bus for any devices that are not defined in the configuration file. Any devices found will be added with default options and their device topic set to {address}. Optional, default false.

Single 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 single device definitions:

Option	Description
address	The device’s address, can be 7 or 8 bytes, can use w1 style xx-xxxxxxxxxxxx. MUST BE IN SINGLE QUOTES ''.
name	Friendly name for the device. Substitutions: {device_id} will be replaced with the device definition section name. {device_type} will be replaced with the device type (ex. DS18B20). {address} will be replaced with the device’s FULL 8 BYTE ADDRESS. Optional, default {device_id}.

Multiple Device Definition

It is also possible to define settings for several devices at the same time. Settings from single device definitions apply here also, except for those shown below.

Option	Description
address	Instead of a single address you can specify a list of addresses.
name	For multiple device definitions, name can be a single name or a list of names the same length as the list of addresses. An additional substitution {index} is available when a list of pin numbers is given. It corresponds to the pin’s index in the list plus first index. If a single name is given and the substitution {index} is not present, the name will have the index appended to the end like {name} {index}. Optional, default {device_name}.
first index	Will be added to device’s index in the list of addresses when subsituting {index} in topics. Optional, default 0.