A smart wearable device (such as smartwatch) with a tiny screen is simply way too small to perform common multi-touch commands like pinching, rotation, and other gestures. Placing two fingers on the screen will block most of the display area. Typing data on the small screen is also close to impossible on wearable devices.
A US patent granted on October 15, 2019, to INNOVENTIONS, Inc., a private Houston-based company perhaps offers a solution. The patent teaches about systems and methods to improve the user interface with wearable devices like a smartwatch. It assigns one or more virtual passive touch pads on the surface (back hand) adjacent to the smartwatch, where the user can tap, drag, draw characters or perform multi-finger gesture commands which are captured by the smartwatch. Thus, generic tactile touchpad inputs to the device are simulated by the assigned virtual passive touchpad without the need of placing an actual tactile touch pad device on that area.
The touch locations on the assigned virtual touchpad area are captured by one or more side looking cameras. The cameras detect one or more finger touch points relative to the captured image of the back hand surface. They can also detect complex gestures including hovering, touching (or tapping), and dragging.
The side looking cameras are also assisted with sound/finger tap sensors and movement sensors. The data from the sound/finger tap sensors is compared with the gesture analysis of the cameras to better pinpoint the position of the user's fingers over the virtual touchpad.
The sound/finger tap sensors comprise a microphone and digital signal processing (DSP) interface to filter legitimate finger tap sounds and notify the processor. DSP action may be performed by the processor, or may be performed by a built in microcontroller of a "smart" sound sensor.
