A streamlined method of adding touchless swipe right, swipe left, proximity, and tap control to any device by using a digital proximity sensor and two discrete infrared emitters is being demonstrated by the Optoelectronics group of Vishay Intertechnology, Inc. in a special demo kit that is available for order now.
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 off an object - a hand, for example - 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 of the signal from the emitter over which it is directly located. 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 into 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.