These technologies are based on resistive touch screens and add multi-touch support including some wicked features like pressure, multi-touch with fingers and objects (e.g. styluses). Obviously this is a huge benefit compared to capacitive multi-touch screens which only support conductors (e.g. human flesh). Of course thse technologies are not without problems: jitter, incorrect pointer placement, incorrect assigment of touch IDs etc.

For a detailed comparison of resistive and capacitive technologies look here, although not everything applies for the technologies presented in this post.

In general there are three major issues that require attention when developing for multi-touch:

  1. multi-touch cursor location
  2. multi-touch cursor tracking
  3. correct assignment of a unique ID to each touch point /cursor
  4. collaborative interaction with  multi-user identification/classification e.g. assigning unique ID to each user’s touch points /cursor

Of course the fulfillment of these issues depends on the platform and application that we are developing. In many cases, namely mobile touch phones, in their current context of use, do not necessarily require multi-user input support.

Currently DiamondTouch is the only solution that argues to support and fulfill all these issues (Circle Twelve).

EETI touch solutions also introduces a touch driver that supports multi-touch on analog matrix resistive (AMR) touch-screens:

http://www.youtube.com/watch?v=fSzO7DS48Bc

Another manufacturer of AMR is Young Fast?

Stantum introduces a new multi-touch software framework, called TouchPark which is designed for operating systems like Symbian, Windows Mobile, and Android,  plus added support for microcontrollers including TI Zoom, Freescale i.MX. which solves many of those problems.

How PMatrix™ works

It watches each grid intersection of the touch-panel’s matrix and reports any change of electrical characteristics. Thus, the controller delivers an exact image of what’s happening on the touch screen surface in the most reliable way, namely with a matchless acquisition frame rate offering extremely fast response.

How it works