Touch sensors avoid environmental wear and tear

Flexibility, reliability and performance were key factors in white goods specialist Haier's choice of user controls for its latest generation of washing machines.

The PSoC CapSense from Cypress Semiconductor has been used to enable the touch sensing interface inside several models of Haier washing machines and water heaters.

The CapSense solution provides Haier a sleek interface attractive to consumers, and eliminates the deterioration experienced with mechanical buttons and switches.

"Cypress's CapSense is used in our washing machines' touch sensing buttons", says Xu Sheng, Director of Technology Development Department, Haier Washing Machine Business Unit.

"Among all white goods, washing machines face the most severe operating environment".

"Haier has very strict reliability requirements for touch sensing input solutions, and CapSense was selected over other solutions because of its flexibility, reliability and performance in the presence of humidity, vibration, high temperature and interference".

"Meeting the high reliability standards of Haier, a leading home appliance company, is a resounding endorsement of Cypress's CapSense solution", says Carl Brasek, Business Unit Director for Cypress's CapSense products.

"This design win is a testimony to CapSense's reliable sensing operation in harsh environmental conditions".

A single CapSense device can replace dozens of mechanical switches and controls with a simple, touch-sensitive interface.

CapSense-based "button" and "slider" controls are more reliable than their mechanical counterparts because they are not prone to the environmental wear and tear that affects exposed buttons and switches.

Cypress has garnered well over 100 CapSense design wins worldwide in applications that include mobile handsets, portable media players, white goods, computers, printers and automotive, among others.

Capacitive sensing is fast becoming the solution of choice for front-panel display and media control applications.

Increased durability, decreased bill of materials (BOM) and a clean, minimalist appearance make this elegant interface attractive to a wide range of designs.

With Cypress's CapSense interface, a finger on the interface forms an electrical connection with embedded sensors, which work with the PSoC device to translate data about the finger's presence into various system control functions.

The sensor itself is a copper pad on the PCB, not an actual component.

All of the circuitry for controlling the sensor is inside the PSoC device.

Cypress's CapSense solution offers system designers numerous advantages over capacitive sensing products built around modules and subassemblies, including increased flexibility, reduced board space and lower cost.

Because of the unique PSoC architecture, designers can easily integrate multiple functions (e.g, LED drivers and LCD displays), in addition to capacitive sensing.

The PSoC CapSense solution also delivers benefits such as easy communications using either I2C, SPI or USB interfaces, the ability to implement both trackpad (x-y matrix) and linear slider applications with the same device, and the ability to make quick design changes using the flash-based PSoC architecture.

In addition, users can complete CapSense designs quickly and easily using preconfigured and verified "user modules" within Cypress's PSoC Designer 4.4 integrated design environment.

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