Skinetic & HSD

Wideband haptics

Common vibration motors offer a single setting. An eccentric rotating mass motor (ERM) ties frequency and amplitude to its voltage. A resonant actuator (LRA) only vibrates efficiently around its resonant frequency. Actronika worked with wideband actuators, of the VCM type: frequency and amplitude were set independently from 10 Hz to 1 kHz, like a loudspeaker built for touch. A pulse, a texture or a vibration each had their own signature.

Actuator mapping

The twenty actuators were spread across the torso, back and sides, following an assessment of tactile sensitivity on the torso. An effect was either played on a single actuator or interpolated across several neighbouring ones to create apparent motion: the sensation was then felt between them and could travel across the body.

Designing for intensive use

The first customers were VR arcades and studios, where the vest changed wearer every session. An operator could not buy one vest per size, so Skinetic was designed to cover XS to XXL. The garment, developed with the Paris workshop Les Vertugadins, held the actuators against the body whatever the build. The mesh lining was quick to swap between uses and easy to wash. The 10-hour battery covered a full operating day.

HSD, a multichannel haptic architecture

Since the actuator was driven like a loudspeaker, HSD was designed as an audio amplifier. It took a multichannel stream, one track per actuator, and amplified each channel. Over USB, it showed up as a standard audio interface that Unitouch, a DAW or custom code could use with no dedicated driver and no proprietary protocol. It also accepted actuators from other manufacturers, provided their impedance matched. The architecture is patented (FR3127829B1).

The first version was wired, for headsets tethered to a PC. VR hardware then diversified, with standalone headsets and wireless streaming from a PC, while existing setups stayed in use. Skinetic had to work in each of these configurations.

Yet twenty audio tracks exceeded Bluetooth's bandwidth and came close to Wi-Fi's. With a standalone headset, the Bluetooth link therefore carried only commands, and Unitouch's rendering engine, embedded on the board, synthesised the effects locally. When streaming from a PC, the vest joined the headset's Wi-Fi network and received the full stream, as over USB. For developers, nothing changed: the same haptic asset played whether the engine ran in the game or on the board.

The principle behind this architecture took shape in an earlier project on haptic car seats. Offered as a development kit, the board was aimed at professionals and research labs. It was used in experiments on office chairs, cinema seats and even beauty masks.

Equipping studios and players

Every game had to be adapted: one effect per event, composed and then placed on the body. To grow the catalogue of compatible games, four workstreams ran in parallel:

• Unitouch, to compose effects and integrate them into Unity or Unreal, and a development kit sent to VR studios.
• Mods of existing games, such as Beat Saber or Half-Life: Alyx.
• Deals with studios and arcades.
• A compatibility layer, so that effects and integrations built for bHaptics worked on Skinetic.