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AndrOBD MQTT publisher

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Erwin Scheuch-Heilig edited this page Dec 15, 2017 · 2 revisions

AndrOBD MQTT publisher

AndrOBD shall be extended with a feature to publish a selectable set of OBD data items to a configurable MQTT message broker. The published measurement data shall be usable in various home automation systems.

Architecture

  • The extension shall be installable as a separate apk package.

  • The extension will NOT be executable as stand alone application

  • The extension package will be invoked and utilized by the AndrOBD application

  • The operation of AndrOBD shall NOT be dependent on the existence of the extension package.

  • All configuration activity concerning the extended functionality shall be handled by the extension package

  • Storage of configuration settings concerning the extended functionality shall be stored with the extension package.

Functionality

  • The AndrOBD MQTT publisher shall forward OBD vehicle data gathered from AndrOBD to a configurable MQTT server.

  • The extension shall connect to a single MQTT message broker as a publishing client using existing network connection.

  • All AndrOBD data items which are selected for display/update shall be selectable to be published to MQTT.

  • Publications shall be sent as a bulk of separate MQTT messages.

  • Publication shall be triggered automatically in a cyclic loop.

  • The time between publications shall be adjustable.

  • It shall be possible to trigger a publication manually.

MQTT messages

  • Each OBD data item shall be published as a single MQTT message.

Names

  • MQTT messages shall be named by the existing mnemonic names as they are currently defined in the AndrOBD data model.

  • These message names shall be prefixed by the configured MQTT message prefix.

Values

  • Data item values shall be published in the dimensions, resolution and measurement units as they are shown in AndrOBD data display.

  • Data item values shall be published with the most current measurement of corresponding OBD data items

  • There shall not be any additional processing like aggregation, averaging etc.

Configuration

  • Following generic parameters for publication shall be configurable:

MQTT parameters

  • Host Name / IP address
  • Port number
  • User Name
  • Password
  • MQTT message prefix

Update parameters

  • Update cycle time [s]
  • OBD data items
    • Selection of subset of AndrOBD data items for display.
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