Posts

Do I need to consider integrating multi-touch into the next generation of my touch products? – Joe Kennedy, New Mexico

Dear Joe:

Touch guy recalls, as a young lad, seeing the brand new and largely passenger free 747’s landing at LAX – this was called the Judas Goat phenomena because no self-respecting airline would be without the behemoth, even though they hardly had enough money to buy one and there was not enough passengers to fill one.

The same concept applies to touch screens. Multi-touch projected capacitive has rapidly grown to be the second largest selling touch-technology (behind analog resistive), even though, other than pinch and expand, there are hardly any software programs that make use of all those fingers. Microsoft has demanded 10-finger touch with lightening quick response to even be considered worthy of being certified.

So, yes, Joe, I do not even have to ask what your product is, you have to do it, and hope that the need comes – just like the passengers that eventually filled the 747’s… There are two real and important reasons why you need to do it, the most important is that projected capacitive will not wear out and the second is that the image quality is really excellent. Add to that, the prices are expected to fall by 50% sometime this year and you have everything you need to make the plunge. And if your application requires pressure sensing (screwdrivers, long fingernails and scalpels), you can now pick the MARS multi-touch product.

Until next time,
Touch Guy

Do I have to use special software to use my touch screen? – Sandy Claws

Dear Sandy:

Wanting to keep things simple, Touch Guy’s answer is “No and Maybe” (this is my new alternate answer to the usual, ‘It depends’). For those of you using a USB-connected system, the touch screen will look like a mouse to your software and because virtually all software works with a mouse, nothing is required. For Windows 7, the touch screen will look like a digitizer or several digitizers to accommodate multi-touch (one for each touch occurring at the same time) and nothing new is required to do all of the cool gestures like pinch, rotate and shrink. Similar multi-touch support is available for Linux operating systems and some versions of CE (though XP embedded comes with fewer headaches). The technical term for this magic is HID Compliant (HID=Human Interface Device) or in the case of Win7, Windows 7 Tablet Compliant. All of Touch International’s USB projected capacitive systems are compliant and will work without having to do anything extra.

The “Maybe” answer comes in to play when systems still run on serial (RS232) connections which require a driver to allow the touch screen to communicate with the software. A touch screen generates an X and Y coordinate (and in some cases a Z). The driver looks at the touch coordinate and then looks at the “hot spot” or the place where the mouse cursor was left on the screen. Next the driver moves the mouse cursor with up/down and right/left “mickeys” to the location of the touch and issues a mouse click. And Jiminy Christmas, the touch works with any software! Touch drivers also allow you to control other things such as calibrating the touch screen to different size displays, controlling how hard or light you have to touch the screen, enabling right button clicks and eliminating the mouse cursor from the screen.

Happy Holidays and remember… my touch screens make great gifts!!

Until next time,
Touch Guy

It was with great excitement that I received my projective capacitive multi-touch kit from Touch International. My guidelines for our vendor were to find a touchscreen with multi-touch support and support for security glass. I’ve seen that there is no driver for this touch screen to support multi-touch. And on the other hand we tried to put a glass layer in front of the touch panel and it didn’t work. Another problem we are facing is that if the touch-panel comes near the lcd-panel the touch coordinates are wrong. What gives?

– Daniel Amesberger

Well, TouchGuy hangs his head in shame for letting you down. While the real world performance is fantastic, It turns out that this new-fangled projective capacitive (p-cap) touch is not quite so plug-and-play as the plain-old-resistive-touch. All touch technologies have their idiosyncrasy—resistive touch needs to be calibrated to the display, IR requires that the beams and receptors are aligned, SAW has special bezel mounting requirements, and DST even requires “certified installers”. In its exuberance to ship the p-cap samples to customers, my guys and ladies did not provide much of (read, practically nothing) in the way of a manual. Touch is working hard to prepare the support you need to do your evaluation. For now, here are some things to consider:

1. Although the sensing layer is sealed inside the glass or plastic (which is why it never wears out), there is a front and back. You really cannot tell which is which, so we will be marking the front side..

2. Most of our sensors come complete, so if you want to put your own cover glass on the sample, you will need to make sure you are putting it on the front, and you will need to reset the controller so it can reset the values for the new glass. Normally, cover glass cannot be more than 3mm thick. If you need the cover glass to be thicker, you need a special version of the controller.

3. If you change the cover glass, you may need to use our new wiz-bang GUI control program to reset the sensitivity. This utility will be available next week.

4. When p-cap electronics start-up, a quickie calibration occurs. Normally the sensor will be attached to the display, but if it is not, sometimes picking the sensor up and moving it will affect the sensitivity; note that this only applies when the sensor is moved without being attached to the LCD.

5. In some rare instances, there is a big ‘ol metal plate under the desk or table. A big metal plate will negatively affect the sensitivity.

6. We have multiple controllers—single touch, multi-touch, all-points-addressable, proximity sensing—lots more actually, so you need to make sure you have the one you want.

7. Demonstrating multi-touch requires a multi-touch driver, so you need to install it or you will just get a single touch. When Windows 7 is released, no driver will be needed for USB operation.

Until next time,
Touch Guy