Set automotive properties using VHAL

This guide demonstrates how automotive application developers can test their features in automotive infotainment systems, using Anbox Cloud, without requiring the vehicle hardware.

A video version of this guide is also available:

Prerequisites

Install and initialize Anbox Cloud. Register with the dashboard and log in with your Ubuntu SSO account. Follow Install the appliance to do this in the appliance.

You need an automotive instance that you can stream. Create and test a virtual device shows how to create an instance. Remember to choose Automotive as your instance type.

When you have an AAOS instance streaming, you can adjust the automotive properties using the dashboard or the API.

You can adjust the automotive properties with the Anbox HTTP API.

Inside the instance terminal, install curl to send HTTP requests using the API:

sudo apt update sudo apt install curl

Install jq so that you can parse JSON responses better:

sudo apt install jq

Check the value set for the temperature property currently and observe the response:

curl -s -X GET –unix-socket /run/user/1000/anbox/sockets/api.unix s/1.0/vhal/358614275/49 | jq .

The output could look like:

{
  "metadata": {
    "value": {
      "area_id": 49,
      "float_values": [
        16
      ],
      "prop": 358614275,
      "status": 0,
      "timestamp": 0
    }
  },
  "status": "Success",
  "status_code": 200,
  "type": "sync"
}

Try changing the temperature property:

curl -s -X PUT --unix-socket /run/user/1000/anbox/sockets/api.unix s/1.0/vhal \
  -d '{
    "prop_id": 358614275,
    "area_id": 49,
    "float_values": [22.5]
  }'

Now if you try the GET query again, you should be able to see your changes reflected.

The dashboard has a HVAC panel with which you can control the automotive properties.

For example, try setting the temperature property:

Open the HVAC panel (fan icon in the navigation bar at the bottom).

Select All VHAL properties on the right.

Search for HVAC_TEMPERATURE_DISPLAY_UNITS which indicates the unit of temperature.

By default, the HVAC panel displays the temperature in Fahrenheit while the VHAL properties show values in Celsius. To switch the HVAC panel display to Celsius, update the value from 49 to 50.

Now, search for HVAC_TEMPERATURE_SET. Modify the temperatures for Area 1 and Area 2 and Save.

To change other supported system properties in the VHAL, see Android documentation.