What materials/fabrics will prevent touch screen from operating?

[keith12]

Ever since touchscreens or touchpads (particularly the iphone) debuted, I’ve seen posts asking what materials/objects will work, in place of your finger, to activate the touch screen. I’ve seen everything from hot dogs to sterling silver plus oranges (and, of course, apples) mentioned as objects that will activate the screen.

My question, as part of a school project, is the reverse. Is there some type of thin film or fabric that will act as a barrier to PREVENT your finger from operating the screen? We’ve tried band-aids, scotch tape, electrical tape, dielectric tape (I think), latex gloves and non-latex condoms and the mighty finger has prevailed through all these barriers. We tried the rubber “thimbles” that are used to count money and they will not activate the screen, but this is too thick to really qualify as a film. So does anyone know of a thin barrier that, when placed between your finger and the screen, will prevent your finger from activating the screen? Thanks!

 

[Mitchekj]

A sheet of thin aluminum?

And I use a hotdog to interact with my iphone... is that so wrong?

 

[keith12]

hot dogs are good

the buns also work. the touch pad will still work through aluminum foil

 

[LTX71CM]

The two most prevalent types of touchscreen are resistive and capacitive. I doubt resistive screens could be disabled with a film because if it flexes the force can still be applied to the resistive film and therefore still operate. Thick glass that breaks before bending to touch the resistive film might be an option. As for the iPhone screen which is capacitive you need to add stray capacitance the OS won't detect as a finger or dissipate any to prevent a finger/stylus from being seen. Keep in mind capacitive screens are specifically chosen in some cases because they can still be used from behind plastic, acrylic, glass, etc...

 

[keith12]

Do you think something like a thin (like 2 mil) FR4 laminate material would act as a barrier?

 

[LTX71CM]

I doubt it. It would have to be conductive or really, really thick.

 

[(*steve*)]

I've just discovered something that works like a charm.

I reckon this is homework, so I'm not going to tell you what it is.

But it's conductive, pretty transparent, and it's use is to isolate certain things from static electricity before they're used.

 

[keith12]

not homework!

Hey Steve

Sorry about the delay in replying, but I didn't see your post until just now. Actually, it's not homework, it's a project for an afterschool non-profit tutoring program that I volunteer for. I am one of the tutors(!?), but unfortunately know nothing about electronics...so I give up. Any more hints? The only thing I can think of that is semi transparrent might be wax paper? I already tried scotch tape. Thanks!

 

[keith12]

anti-static bags?

Hey steve

Did some googling. Are you talking anti static bags? If so (or not!) what are they made of? Thanks!

 

[(*steve*)]

Yep, the conductive anti-static bags are just the thing to stop an iphone screen from picking up your finger.

Check out http://en.wikipedia.org/wiki/Antistatic_bag

 

[Phoebe]

aluminum foil, a good choice.

 

[(*steve*)]

aluminum foil, a good choice.

Not if you want to see the screen it's not

Actually neither anti-static bags nor aluminium foil work if you wrap your finger in them. (on my iphone at least)

 

[keith12]

thanks Steve

I really appreciate your help!!

Keith

 

[Mitchekj]

Not if you want to see the screen it's not

He never put that in the specs!

 

[keith12]

not worried about seeing the screen, just looking for a material that when ou wrap your finger in it it doesn't operate the touch screen

 

[Mitchekj]

Aaah, didn't know you had to wrap your finger in it. The idea behind the aluminum sheet was to spread the "touch" across the whole screen.

If that's the case, I'm at a loss.

 

[keith12]

Hmmmm, in that case I guess I'm back where I started. Anyone need a good price on some anti-static bags?

 

[(*steve*)]

Hmmmm, in that case I guess I'm back where I started. Anyone need a good price on some anti-static bags?

As I noted above, they don't work if you wrap your finger in them.

But if you go somewhere that sells PC stuff (especially if they build custom computers) they will probably have a heap in their rubbish.

Or speak to someone who's just bought a hard drive or a motherboard, etc.