16 — HSI

Hand-Screen Input

What It Is

HSI is Hardin Labs' gestural human-computer interface system that transforms any Silixon-PCB or Silixon-HCB surface — including the palm of a Bioid's hand, a tabletop, a wall, or the interior surface of the DART aircraft cockpit — into a fully functional touchscreen and 3D gesture recognition zone without any glass substrate, liquid crystal layer, or separate touch sensor overlay. The system uses an array of micro-ultrasonic transducers embedded in the Silixon substrate to both project a haptic feedback force field into the user's hand above the surface and to receive the acoustic reflection signature of that hand's position, shape, and pressure — enabling simultaneous input sensing and force feedback in a single integrated ceramic substrate.

Sensing Mechanism

Each HSI-capable Silixon panel embeds a grid of piezoelectric micro-transducers at 1 mm pitch, formed by poling the lead-free piezoelectric dopant phase of the Silixon ceramic under a strong DC field during final sintering. These transducers operate in a time-multiplexed transmit-receive cycle at 40 MHz ultrasonic frequency. The transmitted acoustic field reflects from the user's fingertip or palm with a return signature that encodes x/y position to ±0.1 mm, z-axis height above the surface to ±0.5 mm, and contact pressure by the acoustic impedance loading ratio. A local embedded signal processor running on Silixon RAM decodes the acoustic data into pointer events, gesture commands, and force-touch levels within 1 ms latency — imperceptible to the user as input lag.

Haptic Feedback

In transmit mode, the transducer array can produce a focused ultrasonic pressure node — a tactile point of sensation — at any position in 3D space above the surface through acoustic holographic focusing. As the user's hand moves through an HIG virtual interface, the HSI system tracks the hand and projects haptic pressure nodes onto the fingertips at the locations of virtual buttons, sliders, and textured surfaces — making virtual objects feel physically tangible without any mechanical actuator in contact with the hand.