Technical Articles - Cypress.com

The Art of Capacitive Touch Sensing

Sun, 06 Jan 2013 23:02:11 -0600

Touch sensors have been around for years, but recent advances in mixed signal programmable devices are making capacitance-based touch sensors a practical and value-added alternative to mechanical switches in a wide range of consumer products. This article walks through a design example of a touch-sensitive button that can be actuated through a thick glass overlay. To read more on this topic, click the download link above or view the full article on Planet Analog.

Designer's Guide to Rapid Prototyping of Capacitive Sensors on any surface

Sun, 06 Jan 2013 22:55:06 -0600

This article discusses how to replace the mechanical buttons on a product with a smooth and sleek touch-sensitive surface. It presents the concept of prototyping capacitive sensors on any nonconductive surface using silver-ink pens and copper tape. Topics included are capacitive sensor basics, silver-ink and copper tape, and construction technique. Measured results are presented for sensors applied to the back side of a simple acrylic sheet. To read more on this topic, click the download links above or view the full article on Planet Analog.

Capacitive Sensing Builds a Better Water-Cooler Control

Wed, 02 Jan 2013 04:59:09 -0600

Capacitive sensing offers developers a new way to interact with users that overcome the traditional problems associated with mechanical levels or push button switches that engage a solenoid controlled value. Exploring the use of capacitive sensing in a water cooler illustrates not only how capacitive sensing can make devices more reliable but also how the controller managing capacitive sensing can take on additional functions to add further value to customers as well as reduce maintenance expenses. To read more about this topic, visit Planet Analog.

Capacitive Touch Switches for Automotive Applications

Fri, 03 Aug 2012 04:37:23 -0600

Today's cars have far more switches and buttons than earlier models. Not only are there more, but they also need to be easily installable into increasing more contoured control surfaces. They also have to be cost effective, ruling out hermetically sealed switches. One approach gaining momentum is to convert to capacitive touch switches (cap sense). With no mechanical parts, as well as the ability to conform to contoured surfaces, cap sense switches provide the reliability and cost point required by the automotive industry. This article looks at how to implement capacitive sensing interfaces in automotive applications. To read more on this topic, click the download link above or read the full article on Automotive DesignLine.

Automotive HMI Redefined

Tue, 31 Jul 2012 05:50:18 -0600

Human Machine Interfaces, or HMIs, traditionally consist of multiple systems which allow drivers to interact with their vehicle In today's automotive designs, the HMI also displays any feedback from the vehicle to the driver. This interaction begins the instant one unlocks the car door, continues while driving, and ends the moment the driver gets out and locks the car. It involves the optimal balance of the driver's sensory inputs to make the driving experience both safe and enjoyable. Some of the more commonly recognized HMI system modules for enhancing the driver's experience are keyless entry, power seats control, side mirror control, occupant detection, and most importantly, the vehicle's center stack where the majority of human-machine interactions take place. To read more, click the download link above or visit Automotive DesignLine.

Applications and Considerations of Capacitive Proximity Sensing

Mon, 09 May 2011 16:00:35 -0600

Proximity sensing enables a range of unique usability, design, and functional benefits for end-users of industrial applications. For example, light guides can be used to enhance accuracy of user interface selection in dark environments. Coupled with the use of capacitive sensing, user interface keys can be hidden from view when fingers are not in proximity of the keys. Proximity sensing can also be used in conjunction with Bluetooth devices to decrease connection negotiation lag from sleep. This article will focus on key factors associated with mechanical and system design to achieve high-yield proximity designs in production, including sensor to ground coupling and managing LCD noise. This article presents some common applications of proximity sensing as well as considerations that will greatly maximize design success. To read more, visit EDN.

Learning about Capacitive Proximity Sensing by Building a Theremin

Fri, 16 Jul 2010 08:27:09 -0600

Capacitive Proximity Sensing is a method to determine how close two items are to each other. In many cases, it is used in user interfaces to measure the distance a finger is from a sensor. Capacitive sensing is useful in many applications because it provides an input method with no moving parts.

Often when learning a new technology, it helps to have a project in mind that is simple enough that the majority of design and troubleshooting is directly related to implementing the technology. It can also help keep an engineer’s interest and drive going when the project is interesting and exciting. To this end, this article describes how to make a rudimentary Theremin – a musical instrument with two controls: pitch (frequency) and volume (amplitude) – to illustrate the basics of working with capacitive sensing. To read more, click the download link below or visit EN-Genius.

Add Capacitive Sensing to a Digital Handset

Thu, 03 Dec 2009 17:09:39 -0600

Manufacturers are focusing on innovative techniques for replacing space-consuming buttons and switches without compromising the cell-phone user interface (CPUI). A powerful reduction technique adopts capacitive sensing into the CPUI.

Capacitive sensing enables lower cost, robustness, flexibility, and an intuitive CPUI without breaking compatibility with existing form factors and feature sets. Capacitive sensing functions can be combined with other standard functions, such as white LED driving and battery charging to further drive cost down. To read more on this topic, view the full article on CommsDesign.

Metallic spring sensors serve as rugged, reliable capacitive sensors

Fri, 17 Apr 2009 17:47:25 -0600

Capacitive sensing provides a robust alternative to traditional mechanical switches. However, some applications cannot accommodate the physical implementation of a printed circuit board directly under an overlay or attached to the device case. Examples of such applications are "white goods" such as cooktops, washing machines, refrigerators, microwave ovens, and others, as well as various vehicle electronics, such as radio sets, TV tuners, dash boards, and seat occupant detectors.

Metallic spring sensors may be used as an alternative to solid conductive sensors. This allows placement of the PCB at a distance from the overlay while providing a reliable sensor connection even under operating conditions of strong vibration or sharp temperature changes. In addition, springs provide added functional possibilities, such as backlighting, and combinations of mechanical and capacitive buttons. To read more, visit EDN.

Improving the Accuracy and Efficiency of Junction Capacitance Characterization

Thu, 13 Nov 2008 00:00:00 -0600

In this paper, the on-wafer measurement of junction depletion capacitance is examined. This work provides an in-depth discussion of possible probing configurations which can be used. It outlines a method to consistently measure the junction capacitances accurately. The results from this method compare favorably with those extracted using S-parameter measurements. Additionally, methods are formulated to reduce the number of data points required for parameter extraction while at the same time maintaining a high model accuracy.

Add Capacitive Sensing to a Digital Handset