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What’s the difference between resistive multi-touch and projected capacitive multi-touch and why would someone choose one over the other? – Mike Zimmerman, South Carolina

Dear Mike:

I am the long-time cheerleader for projected capacitive touch technology, so my answer may be biased, but here it is:

If you are a mechanic using a touch screen to fill out an overpriced car repair estimate, you should use resistive multi-touch touch screens (MARS); everyone else should use projected capacitive multi-touch technology (MulTI-Touch).

Touch Guy’s projected capacitive mantra is 1) it will never wear out, so it’s a better investment, 2) it has great optics and 3) it is multi-touch capable. The only downfall to projected capacitive technology is that it will not respond to every input device (i.e. pens, pencils, credit cards); only those that are conductive.

For all the mechanics out there, here is why you want to use Resistive multi-touch:

Let us assume that our mechanic, Mike, will use a torque wrench to reach over and activate the diagnostic machine’s touch screen – this requires a pressure sensing touch screen (aka resistive). Or when he fills out the repair estimate on an electronic recorder, he can use the nearby pen or pencil to input information. Mechanics will also like the palm rejection that MARS has. Palm rejection is achieved by ignoring touches in part of the screen and accepting them where the writing will occur (this is used in signature capture devices). Plus, when every nano-watt counts, resistive technology consumes less power than capacitive.

But using resistive multi-touch technology comes at a cost when comparing it to projected capacitive technology. MARS is really just a 4-wire resistive touch screen cut up into severalf small 4-wire touch screens, so it will wear out with use. And the optics are not as good as projected capacitive because it has the same reflections of a standard 4 or 5-wire resistive touch screen. MARS-groupies point out that resistive touch has worked plenty-good for the last 25 years and the benefits of multi-touch, low power and no-drift coordinates make it a long term winner. Touch Guy is not convinced but thinks multi-touch resistive is a niche product.

Until next time,
Touch Guy

Hello Touch Guy! My name is Jeffery. I have a new product that I would like to finish the prototype for, but…I cannot find a flexible, yet durable touch film (no glass) I can use. The size needs to be approximately 12″ x 12″ (+/- 1 or 2″) but I am willing to look at other options. I am talking to the TV show, Shark Tank, and counting on a few other companies to bring this product to market. The problem I am facing is manufacturing’s willingness to deal with me. I’m not asking for something for free and am willing to pay for a sample unit, but the supplier must be able to supply 1,000 units at a time. Do you have any suggestions for companies that can provide a flexible touch film? – Jeffrey Gelman, FootMouse TouchPad Team

Hey Jeffery….relax, Touch Guy is here to help.

I hear this story a lot, unfortunately most often from my American competitors. And, a Google search of “touch screens” lists the company most likely to help you–Touch International-on page 12, even though they are the second largest US manufacturer of touch products. (Hear that Bing?)

But let’s get to your….hmmmm, opportunity. First, any company should listen to what you are doing. We like to think of ourselves as experts and will try and fit one of the touch technologies to your needs, instead of the other way around….sometimes it even means sending you to one of our competitors. Secondly, if this is your first touch-based product, to save you time and money, we will suggest one of our inexpensive demo kits or off-the-shelf products.

If you truly need a custom part or electronic controller, there will be a non-recurring engineering charge (NRE). NRE typically starts at $2,500 and can be much higher depending upon your application requirements, etc. The NRE covers an engineer to design your part and a CAD designer to make the approval documents. Once approved, the NRE also will cover the manufacturing drawings and then the “artwork” to make the various silk-screens and decoration masks. Then the machines are programmed to your specific part, as specified in the “proto-build package” of workstation instructions. By this time, the materials will have been obtained and used to make the prototypes. Touch International has a prototype line, identical to their production lines, so that we can make new parts and not be preempted by revenue production. Best yet, Touch International is an equal opportunity company, so anybody willing to pay NRE is never kicked out of line once their project has started. Just so you know, it is rare that Touch Guy sees any profit from a prototype.

The only problem Touch Guy is having is your desire to build 1,000 parts on a first run. If you are asking for mature touch screen technology, 5-wire or 4-wire resistive, then we may not try to talk you out of it. But, no matter how hard we all try, there is usually something that needs to be changed or tweaked after the prototypes are produced and nobody wants 999 almost-worked-perfectly sensors.

So, talk to Touch Guy, we will see what we can get to meet your needs…and good luck selling the concept to the ba-zillion-aires. Oh, and yes, we make flexible touch film in your size.

– Touch Guy