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  Date: 25/11/2013

Gesture control tech: One on Infrared based and other an-ultrasonic

Non-touch gesture control interfaces is gaining popular for use in consumer electronics as well as to control desktop computers and automotive infotainment sys. There are two recent announcements on the technologies related to gesture control; one from Vishay based on Infrared, and other from Elliptic Labs based on ultrasonic waves.

Vishay Intertechnology has come out with a gesture controlled interface system based on digital proximity sensor and two discrete infrared emitters.

Vishay’s new gesture control sensor board consists of a Vishay Semiconductors VCNL4020 integrated proximity and ambient light sensor and two of Vishay’s VSMF2890RGX01 infrared diodes mounted on either side of the sensor. The detection of gestures using these components is accomplished by comparing the signal of infrared light coming from each of the emitters. The emitted infrared light is reflected from an object, for example a hand, and then detected by the VCNL4020 proximity sensor. In order to differentiate between the signals coming from either emitter, the emitters are multiplexed, meaning they are pulsed one after the other in quick succession. A high radiant intensity of 80 mW/sr typical at 200 mA allows for the detection of hand gestures up to 25 cm above the sensor board.

The proximity signal is then read out between each pulse via the I2C bus interface. When a hand is in the proximity of the board, it will reflect more signal from the emitter it is directly located over. If the hand is then moved across the board, the signal from one emitter will increase before the other. It is this time difference of signal strength that is analyzed to determine if a swipe gesture was made and in which direction.

Sensors that recognize and respond to hand gestures are being designed in to consumer products with increasing frequency. For example, users can advance to the next page of a recipe displayed on a tablet PC without touching the screen. The Vishay gesture control sensor board supports swipe right, swipe left, tap, and push in and out. For example, swipe right and left would be used to move to the next or previous page, picture or selection. Tap would be used to make a specific selection and would be similar to touching the screen. Push in and out would be used to zoom in or out, turn the volume up or down, or change backlighting intensity.

A webinar showing how the demo board works is available at http://www.vishay.com/videos/optoelectronics/gesture-control-system . Detailed information is also available in the following application note: http://www.vishay.com/doc?84218.

The gesture board demo kit is provided free of charge as an add-on to the VCNL4000 Demo kit. Customers who have already purchased a VCNL4000 Demo kit may request a free gesture board add-on by sending an E-mail to sensorstechsupport@vishay.com

Elliptic Labs’ ultrasonic gesture control solution is using Wolfson’s Audio Digital Signal Processor (ADSP) platform. This ‘always on’ ultrasonic, low power touchless gesture control is designed for consumer electronics devices such as smartphones and tablets, as well as for in-car infotainment.

Using sound waves to interpret hand movements, Elliptic Labs says its solution is currently the only technology integrated into portable devices that can deliver 3D gesture control with a 180-degree field of view at all sides of the device. It can identify near-field and mid-air gestures with focus up to 50 cm.

Andy Brannan, Chief Commercial Officer at Wolfson Microelectronics commented: “Along with voice control, touchless gesture control is fast becoming one of the next generation human-machine interfaces for mobile and wearable devices. The form-factors and use cases of new devices increasingly make touch control impractical. The barrier to this new technology being more widely adopted has been power consumption. Wolfson removes this barrier to enable true ‘always on’ handsfree control in all situations. Elliptic Labs is at the forefront of this new technology trend, and we are delighted to work with them to port their ultrasonic touchless gesture control solution onto our ultra-low power platform.”

Laila Danielsen, CEO of Elliptic Labs said: “Integrating Elliptic Labs’ ultrasonic touchless gesturing solution with Wolfson’s ADSP platform gives device manufacturers a way to offer the advantages of touchless gesturing to consumers while ensuring extremely low power consumption. Today, OEMs are keen to enable mobile devices to be ‘always on and always looking’ for hand gestures while consuming minimal power, and working alongside low power voice control. Our combined technology can ensure this becomes a reality for the market.”

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