Overcoming Capacitive Sensing Limitations

(Editor's note : there is a linked list of additional related items below the “About the author” section.)

Touch technology comes in two flavors: Resistive and Capacitive. Although it is a lower-cost approach for touch-sensitive applications, resistive-touch technology has significant disadvantages such as wearing away with time, and difficulty when implementing normal buttons.

Capacitive touch-sensitive buttons offer the following advantages over tactile buttons:

  • Ease of Product Assembly and Durability
  • No More Jitter
  • Lower Cost and Innovative Interfaces

However, there are limitations of capacitive sensing which can pose a significant hindrance in making tactile buttons entirely obsolete:

  • A system cannot detect whether a capacitive sensor has been pressed during power up
  • Unlike Tactile buttons, capacitive sensors do not provide tactile feedback to users

This article discusses, in detail, the above-mentioned problems and their solution. It is presented in pdf format (no registration required); to read it, click here.

About the author
Pushek Madaan is currently working with Cypress Semiconductor India Pvt. Ltd. as a Senior Application Engineer. His interests are in designing embedded system applications in C and assembly languages, working with analog and digital circuits, developing GUIs in C# and, above all, enjoying adventure sports.

Related articles of interest
1. Using capacitive sensor user interfaces in next generation mobile and embedded consumer devices, Mariel Van Tatenhove and Andrew Hsu, Synaptics, Inc.
2. Designer’s guide to rapid prototyping of capacitive sensors on any surface, Mark Lee, Cypress Semiconductor Corp.
3. Capacitive sensors can replace mechanical switches for touch control, Wayne Palmer, Analog Devices Inc.
4. Building a reliable capacitive-sensor interface, Wayne Palmer, Analog Devices, Inc.
5. The art of capacitive touch sensing, Mark Lee, Cypress Semiconductor Corp.
6. Practical considerations for capacitive touchscreen system design (Part 1 of 2), Yi Hang Wang, Cypress Semiconductor Corp.
7. Basics and implementation of capacitive proximity sensing (Part 2 of 2), Ganesh Raaja, Cypress Semiconductor Corp.
8. Touchscreens 101: Understanding touchscreen technology and design, Steve Kolokowsky and Trevor Davis, Cypress Semiconductor Corp.

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