Appliance Design - February 2008 - (Page 20) CONTROLS & SENSORS alter the reference level slowly in the direction of the signal change using a feature called drift compensation. This feature only works when the signal changes are small and known not to be the result of human touch. The company’s algorithms can also help ensure that the correct key is detected among tightly spaced keys, through its Adjacent Key Suppression (AKS®) algorithm. This process runs constantly, helping to discern the user’s actual intent. If, due to an analysis of keys’ signal strengths, it believes that the actual button being pushed is the letter “D” for example, it will lock out the letters “C” and “E” and any other nearby keys. Adding to the robustness of many of Quantum’s QMatrix products is the self-diagnostic capability it has through a tions, the company’s product range has expanded from chips for single touch buttons, to multitudes of buttons, keys, slides and wheels, projected capacitive touch screens, and combinations of these features. The technology can sense through any non-conductive material such as plastic, glass, and even wood, and the substrates can be of sizes as thick as 5 mm or more. This versatility, and multiple capabilities, can be seen in some recent applications. For example, Samsung offers a microwave oven with Quantum’s touch scroll-wheel. The oven uses the company’s QT511 QWheel rotary-scrolling chip that consists of a ring electrode array placed behind the plastic panel. Three capacitive QT sensing channels are connected to this ring, and the resulting signals are processed to provide 128 positions. The result is output on an SPI serial interface. The device can be set to sense through panels up to 3 mm thick and even works through gloves. For eight decades, capacitive technology has been a versatile industry workhorse. The microwave oven is just one application in which capacitive technology is being used. Today, Quantum’s devices are found in mobile phones, home theater equipment, computer peripherals and many other products. And, tomorrow’s applications may even be broader as touch screens become even more content driven. A cooking recipe, for example, could appear on a stove’s touch screen and the choices that are made can help program the oven. < For more information, enter . . . . . .300 Or email: info@qprox .com A cooktop from Gorenje, a Slovenian kitchen appliance manufacturer, features both the QSlide and QTouch technologies. HIGH PERFORMANCE HVAC/R TEMPERATURE SENSORS Temperature Sensors · Wide range of unit housing materials · Wide temperature range (from -40°C to +300°C) · 0.1 to 1M Ohm resistance range · Long term stability · Precise temperature measurement · Custom probe length and thread sizes · Variety of thermistor casings Applications Include - Heating - Central Air - Water Temperature Control Systems - Appliances For Information log on to www.zettlercontrols.com ZETTLER CONTROLS, INC. Phone: 949-360-5840 · Fax: 949-360-5839 75 Columbia, Aliso Viejo California 92656 For more Information Enter 107 www.zettlercontrols.com February 2008 built-in Failure Mode and Effects Analysis program. This capability has been incorporated into certain QMatrix chips to provide an extra level of certainty, says Ard. “FMEA is particularly interesting in cooking appliances,” says Ard. “You wouldn’t want the appliance going on by itself in the middle of the night.” An FMEA enabled QMatrix chip does constant self-diagnostics. It checks for shorts and opens in the matrix, and probes the matrix itself using special diagnostic acquisitions to make sure keys are still there and working correctly. Via the chip’s serial interface, the host appliance controller can interrogate the QMatrix device for complete error information, and as a result take an informed decision on what to do – for example, to shut down the appliance, in the case of a critical key failure. Because of these innova- 20 applianceDESIGN AD02082ZettCon.indd 1 www.applianceDESIGN.com 11/30/07 10:14:46 AM http://www.zettlercontrols.com http://www.zettlercontrols.com http://www.zettlercontrols.com http://www.appliancedesign.com
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