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My engineers claim gestures on multi-touch resistive do not work nearly as well as they do on projected capacitive (PCT) used in a variety of consumer devices, like the iPhone – why is this? Have there been any recent breakthroughs with resistive multi-touch? I would appreciate any new input on this subject.

Hi Alex:

When you are comparing iPhone/iPad projected capacitive (also called PCT or P-Cap) to any other (even identical) projected capacitive sensors, you may not find the performance to be as good as Apple ’s product.  How can this be?  It is because Apple has had a really big head-start (as in years).  You and yours are playing catch-up, and it will take a while for you to integrate the prior art (yes, Apple did not invent multi-touch) with the new, to achieve the same thing.

Here is a good example:  Using a multi-touch demo, you can use the pinch gesture to make the picture really small….so small, that you will not be able to “catch” the corners and expand it…it will stay really small untilTouchGuy_Basic you reset the program.  Apple has anticipated the picture getting too small, so their software will accept nearby fingers and “guess” that the user wants to expand that photo, and it will.  There is a lot of anticipation in the iXX software that makes it better than your stuff.  Touch Guy is a hardware person, so you can guess that he will point the blame finger at the software folks.

Now to your original question…  MARS is different only in the pressure required to enable the gestures.  Otherwise, the gestures should be the same and the performance the same as projected capacitive and better, of course, with input from pens and pencils.  Keyboard entry is noticeably better with sure-footed MARS than with projected capacitive, which seems to often “guess” wrong at which key you wanted (auto correct to the rescue).

For more info on multi-touch, check out Touch International’s Putting the ‘Touch’ in Multi-Touch White Paper.

Touch Guy

MulTI-Touch Projected Capacitive Developer Kit

Creating Multi-Touch Experiences with NUITEQ

So with all the multi-touch products out there (and the number seems to be growing exponentially), there appears to be is a multi-touch software shortage, believe it or not. There are very few multi-touch software programs (or developers) out there to assist OEMs with showcasing their multi-touch solutions. Short of creating software from scratch or simply using the Microsoft Surface Touch Pack for Windows 7, OEM’s software options are slim at best.

Enter NUITEQ, a Swedish multi-touch software technology company who provides off the shelf and customized software solutions for interactive multi-touch displays. Its multi-touch software product Snowflake Suite, which is available to SI’s, VAR’s, OEM’s, software developers and end clients, operates on a wide variety of multi-touch hardware technology platforms ranging from camera based solutions and IR overlay systems to capacitive, resistive and other technologies that are integrated in mobile phones, tablets, laptops, desktops and large scale interactive displays.

MulTI-Touch Projected Capacitive Developer Kit
Multi-Touch Developer Kit

Touch International recently partnered with NUITEQ and is running the Snowflake Suite on its MulTI-Touch projected capacitive developer kits, which allows the company to demonstrate its products’ full multi-touch capabilities. The Snowflake interface really gives OEMs an edge because it functions and looks a lot like the iPhone, which of course, is the standard for today’s touch screens.

NUITEQ is quickly becoming a highly recognized company world-wide and has received numerous awards and accolades including Winner of the 2010 Red Herring Global 100 Award and 10th Most Promising Tech Startup in the World by Innovate 2010.

To learn more about NUITEQ, click here.
To learn more about Touch International, click here.

I’m trying to figure out how multi-touch controllers work and have a few questions: Why are certain multi-touch controllers unable to sense more than 2 touches? What are the device limitations? How does a 10-point sensing controller overcome this?

Hi Raji,

So, on this Valentine’s Day you want a date with Multi-Touch? Or are you looking to make that special commitment? Either way, I can help you out …

As Touch Guy says, the best predictor of tomorrow is what happened yesterday.  In the long 25 year reign of resistive touch, the electronics went from dedicated touch controllers, to single ASIC’s, and finally to touch controllers as a simple four or five wire connection to the LCD driver chip. For multi-touch, we are in the early stages transitioning from dedicated controllers to ASIC’s. All of the dedicated controllers communicateTouchGuy_Basic with the host via USB. In Touch International’s case, the communication format is Microsoft Windows 7 tablet, which makes the touches look like a whole mess of absolute mice to the host. Using this protocol format, both Win CE 7 and Win 7 will work using the built in driver. Linux also has a number of open source drivers available, and if you follow the common implementations, this will be easy.

Today you can pick your life partner (or at least your touch screen ASICS), as there are about twenty multi-touch projected capacitive ASICS available, with even more coming. Of course, each has its strengths and weaknesses, some of which are cost, signal strength, noise rejection, pen sensitivity, allowable thickness of cover glass, speed, number of detectable touch points, availability, and so on. And, if you are looking to make that life-long commitment, but are worried about compatibility, then rest assured that of the ASIC’s I know, all have both I2C and SPI interfaces; a few have USB built in, but a USB peripheral chip can be added to any of the interfaces.

Now, if you’re looking to make multiple commitments (think HBO’s Big Love), there is no I2C dependency and you can run multiple partners on the same bus. Some of the ASIC’s have the address hard-wired in, and some ASIC’s allow the programming of the address. Regardless, you can talk to multiple suitors at the same time. Be aware, however, that there is no “standard” touch format on the I2C, as there is with our USB implementation, so how you communicate your touches will be up to you in some cases, and up to the partner chip in others.

And Touch Guy is off to bestow the ladies of his life with chocolate covered cherries.

Ciao.