issue: August 2012 ApplianceMagazine.com
Case Study: Control Panels
High-End Washers Get Custom Capacitive Interface Panels
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The supplier partnered with a multinational manufacturer of major appliances to develop capacitive touchpad panels for two high-end, Class-A energy-saving clothes washers.
Molex Inc.'s capacitive switches and panels use capacitive-field-sensing technology to enable user interfaces with no moving parts.
"Capacitive switch technology offers a proven upgrade to mechanical controls in electronic user interfaces," explained Steve Fulton, engineering manager, Molex. "The washing machine user panels encapsulate imaginative ideas and robust engineering for enhanced functionality, with exceptional product reliability and energy savings."
Designed to Withstand Laundry Room Rigors
The capacitive switch panel designs incorporate solid-state circuitry in an interface that is designed to be highly resistant to multiple key presses, water, dirt, contaminants, and EMI. The supplier engineers its capacitive overlays and panels allow easy cleaning of the appliance. They are available in a variety of cosmetic options, such as in-mold decoration (IMD), glass, or virtually any non-conductive material.
Both washing machine models feature multiple wash options, requiring numerous tightly spaced capacitive key sensors and icons. A single 44-pin microcontroller handles all panel functionality. Universal Asynchronous Receiver/Transmitter communication for sensor reporting and lighting control ensures consistent responsiveness and panel lighting levels in the user-controlled bright and dim modes. The power button has been integrated into the Molex capacitive panels to provide additional power savings when the laundry appliance is not in use; a dead front appearance hides the icons until the power button is activated.
Key features of capacitive interface panel Model A:
* IMD with a curved front surface embellishment.
* Enhanced 17 user touchpad panel keys, plus touch sensing wheel input with 16 user selections.
* Custom LED lighted display with 13 digits and 29 icons.
* Lighting and capacitive sensing from rear of IMD bezel, with 42 additional backlights implemented via light guides and side-fire LEDs.
* Bright and dim mode for every lighting element.
Key features of capacitive interface panel Model B:
* Tempered glass panel with second surface printing provides a mirror-like touchpad appearance.
* Appealing 16 user touchpad panel keys, plus touch sensing wheel input with 10 user selections.
* Custom LED display with 16 digits and 17 icons.
* Lighting and capacitive sensing from rear of the glass, with 31 additional backlights implemented via light guides and side-fire LEDs.
* Fading feature to achieve gradual brightness changes.
A Design-to-Launch Partner
"As a design-to-launch partner, (we) leveraged our global network to deliver innovative and cost-effective panel designs and options that matched our customer's creative concepts, timeline, and budget," Fulton said.
The supplier's capacitive switches and panels are used in home appliance applications as well as in medical, industrial, and other consumer applications. The supplier's products are engineered and manufactured in a vertically integrated environment, with electrical, mechanical, and process engineers located globally. All manufacturing facilities are ISO9000 and ISO14000 certified. Capacitive switch assemblies are qualified through tests based on American Society of Testing and Material standards.