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Vehicle properties
ADAS & driver assistance

HANDS_ON_DETECTION_DRIVER_STATE

What it is

Hands On Detection (HOD) driver state.

Returns whether the driver's hands are on the steering wheel. Generally, this property should return a valid state defined in the HandsOnDetectionDriverState or ErrorState. For example, if the feature is not available due to some temporary state, that information should be conveyed through ErrorState.

If the vehicle wants to send a warning to the user because the driver's hands have been off the steering wheel for too long, the warning should be surfaced through HANDS_ON_DETECTION_WARNING.

For the global area ID (0), the VehicleAreaConfig#supportedEnumValues array must be defined unless all states of both HandsOnDetectionDriverState (including OTHER, which is not recommended) and ErrorState are supported.

How the ID is built

A property ID is a 32-bit value packing four fields. Reading 0x11401017 apart:

FieldMaskValueMeans
Group0xf00000000x10000000SYSTEM
Area0x0f0000000x01000000GLOBAL
Type0x00ff00000x00400000INT32
Ordinal0x0000ffff0x000010170x1017

Reading it from an app

CarPropertyManager mgr = (CarPropertyManager)
        car.getCarManager(Car.PROPERTY_SERVICE);

int value =
        mgr.getIntProperty(VehiclePropertyIds.HANDS_ON_DETECTION_DRIVER_STATE, 0);

This property is read-only — writes are rejected. It fires a callback whenever the value changes.