[MISSING]: Driver development documentation for Haptic Pulse Event

[TheDeveloperGuy]

There is no documentation on this event for drivers. Digging around in the Unreal plugin documentation I was able to find the following:

• Frequency is 0-360Hz
• Amplitude is 0-1

What is missing is what the range of the Duration is (some unofficial sources say 0-5 seconds), and what the driver is intended to do for a duration of zero seconds (which is the majority of the events sent by Home and Dashboard), or an amplitude of zero.

Here is a list of events sent to my controller driver from Home and Dashboard (format is controller ID, duration, frequency, amplitude):

1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 20.000000, 0.200000 0, 0.000000, 20.000000, 0.100000 0, 0.000000, 20.000000, 0.200000 0, 0.000000, 20.000000, 0.100000 0, 0.000000, 20.000000, 0.200000 0, 0.000000, 20.000000, 0.100000 0, 0.000000, 20.000000, 0.200000 0, 0.000000, 20.000000, 0.100000 0, 0.000000, 20.000000, 0.200000 0, 0.000000, 20.000000, 0.100000 0, 0.000000, 20.000000, 0.200000 0, 0.000000, 20.000000, 0.100000 0, 0.000000, 20.000000, 0.200000 0, 0.000000, 20.000000, 0.100000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 20.000000, 0.200000 0, 0.000000, 20.000000, 0.100000 0, 0.000000, 20.000000, 0.200000 0, 0.000000, 20.000000, 0.100000 0, 0.000000, 20.000000, 0.200000 0, 0.000000, 20.000000, 0.100000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 20.000000, 0.200000 0, 0.000000, 20.000000, 0.100000 0, 0.000000, 20.000000, 0.200000 0, 0.000000, 20.000000, 0.100000 0, 0.000000, 20.000000, 0.200000 0, 0.000000, 20.000000, 0.100000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 1.000000, 0.160000 0, 0.000000, 20.000000, 0.200000 0, 0.000000, 20.000000, 0.100000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 1, 0.011000, 1.000000, 0.000000 0, 0.000000, 20.000000, 0.200000 0, 0.000000, 20.000000, 0.100000 0, 0.000000, 20.000000, 0.200000 0, 0.000000, 20.000000, 0.100000

[TheDeveloperGuy]

Also requested 3 years ago here: https://github.com/ValveSoftware/openvr/issues/724#issuecomment-383353802

[TheDeveloperGuy]

Seems that using a minimum duration of 50ms and a minimum amplitude of 0.05 works. Would be useful to know what the driver is intended to do with zero values for duration or amplitude.

[danwillm]

The way I've been doing it is this:

1. Get the duration, in microseconds: duration * 1000000.0f
2. Find the period of the whole haptic event, in microseconds: (1 / frequency) * 1000000.0f

Then to work out how long to have the motor spinning: maximum "on duration" of half the period, and some arbituary minimum duration. The on duration then varies by the amplitude between the set minimum and the maximum of half the period.

[danwillm]

A minimum of 0.05 and this method seems to correlate to the values that are output when using a lighthouse hdk.