3D gesture controller simplifies mobile user interface and saves energy

Nov. 20, 2012
An energy saving smart 3D gesture interface technology developed by Microchip Technology Inc. requires no-touch user interfacing to consumer electronic devices.

When Steve Jobs introduced the iPhone to the market in 2007, he emphasized the need for a natural man-machine interface by pointing out that, "people want to find things and touch them." This natural user interface has now gone one step further thanks to an energy saving smart 3D gesture interface technology developed by Microchip Technology Inc. that requires no-touch user interfacing to consumer electronic devices. It saves energy to boot.

The company's patented GestIC technology employs electric-field (e-field) sensing that enables gesture-based non-contact user interfaces for a wide variety of consumer electronic applications. The technology is implemented in Microchip Technology's MGC3130 IC that offers low-power, precise, fast and robust hand-position tracking with free-space gesture recognition.

The company envisions a wide variety of market applications for its product beyond the consumer electronics market, including industrial, medical, automotive and other sectors.

Because energy-consuming consumer electronics have become a hot button, Microchip Technology's designers designed 3D interfacing with power consumption in mind. The device dissipates as little as 150 µW (90 mW maximum) in its active sensing state. This makes the chip a candidate even for battery powered devices where power budgets are extremely tight. "The MCG3130's low-power design and its variety of configurable low-power modes provide the lowest power consumption of any 3D sensing technology which can be up 90% lower of camera-based gesture systems" says Fanie Duvenhade, director of Microchip Technology's Human-Machine Interface (HMI) Div.

A programmable self wake-up mode draws 45 µA and comprises interrupts that react to user interactions with the device. In the processing mode, the chip dissipates 30 mA at 3.3 V. In a deep-sleep mode, current draw is just 9 µA.

GestIC technology utilizes thin sensing electrodes made of any conductive material. This can be printed-circuit board traces, a touch-screen indium tin-oxide (ITO) coating, conductive foils and paints, and laser-direct structuring approaches, to enable invisible integration behind the device's housing. The ability to use various sensing substrates allows for visually appealing industrial designs that are economical. "You can easily imagine operating an on-off switch, be it a light in a home's bathroom or a switch for operating equipment in a plant, with the simple wave one's hand" adds Duvenhade.

The GestIC technology provides 100% surface coverage, eliminating "angle-of-view" blind spots found using other gesture approaches. On-chip analog and digital filtering, as well as automatic frequency hopping, lets the chip tolerate RF noise. The chip emits little RFI thanks to low transient voltages and slew-rate control.

A low-noise analog front-end includes five receive channels and one transmit channel. The chip performs fast 200-Hz data sampling and 32-bit signal processing and detects objects up to 15 cm away at a detect rate of 200 positions/sec and spatial resolution of up to 150 dots/in. (DPI). It's carrier frequency range is 70 to 130 kHz.

The MGC3130 combines 3D hand gestures with x, y and z positional data to allow for proximity and single-touch sensing capabilities. Other features include two I2C or SPI interfaces, and streaming and positional data ports. Multi-zone support is enable via a master/slave architecture.

Also important is a rich on-chip library --the Colibri Suite--of intuitive and natural human gestures. The suite combines a stochastic hidden Markov model and x/y/z hand-positioning vectors to provide designers with a reliable set of recognized 3D hand and finger gestures that can be easily implemented in their products. Examples include wake-up on approach, position tracking, flick gestures, circle gestures and symbol gestures to perform functions such as on/off, open applications, point, click, zoom, scroll, free-space mouse-over and others. Designers can use this library to get to market quickly and reduce risks by simply matching their system commands to Microchip's extensive set of pre-determined and proven gestures.

In addition, the chip gives designers the flexibility to utilize pre-filtered electrode signals. Development support is available in the Microchip Sabrewing MGC3130 single-zone evaluation kit, part number DM160217. It provides a selectable electrode size of 5 or 7 in. and comes with the AUREA graphical user interface--also available via a free download at http://www.microchip.com/get/S23 which lets designers match their system commands to Microchip's Colibri Suite.

The chip is available in a 5x5-mm 28-pin quad flat no-lead (QFN) package in sample quantities. Volume production is expected in April 2013 at $2.26 each in high volumes. The development kit is available now for $169.

Microchip Technology Inc. , 1-888-624-7435, http://www.microchip.com/get/S2.

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