2 touchscreens, one computer

[Pat Geballa]

Hey Everyone I am new here and not an electrical engineer I am on the mechanical side of the spectrum. I have a question that you guys may be able to help me with for a project. If I am making something like a phone or tablet with 2 separate screens ( think like a flip phone). Is it possible to have one processor/computer and 2 connections to both screens so it can work as one touch screen. The best way i can relate to something already out there is like if you have 2 computer screens with a blown up image so the whole thing is displayed across the 2 screens. Thank you and sorry about the terminology.

 

[fresh_42]

There are switches which allow you to channel two screens into one plug of the computer, a "T" cable. I think that either switching (another switch) as well as doubling the signal (the "T") is possible, but I'm not 100% sure. At least the old interfaces allowed this, don't know whether USB supports it, too, probably not.

 

[Pat Geballa]

Thanks for the quick reply . Yea I remember how to do it with the computer screens but my question is about a similar result but a smaller screen like a phone or tablet. So i would be using a ribbon or something along those lines. Maybe a better way to describe it would be think if you took an iphone and cut it in half to make it a flip phone. Thanks again for the quick answer though !

 

[Tom.G]

To use two separate touch screens the processor has to both write to and read from them independently. An similar concept for a desktop computer would be two disk drives. If you want to write to them independently there must be a way for the processor to specify which drive it is talking to. This is typically done with a cable to each device which connects to its own port on the processor.

A perhaps simpler analogy is a stereo HiFi system where two speakers connect to two terminal blocks on the amplifier.

If you will be building many of these 'things' of yours, you could use the same output from the processor and then add one more wire to select which screen. This requires that the screens sense the voltage on the added wire and that one screen is active when the voltage is low and the other screen is active when the voltage is high. This added wire is used as a "Select" line, a common approach in electronics. The drawback is that stock screens probably don't have the Select capability, so that means a custom designed screen.

Of course similiar, but slightly more difficult, intricacies arise for touch input from the screens.
(for instance what happens when both screens are stroked at the same time?)

Have fun! Sounds like you are on a learning path in computer engineering.

Cheers,
Tom

 

[Pat Geballa]

Hey Tom thanks for the answer. I am hoping to be building many of these things but i have to start with prototype first than patent etc... And yea it looks like I am doing some crash course computer engineering for it to work. Another clue i can give you to how the device will be is think the durability of an old nextel phone but capability of a smartphone. Thats what I am going for atleast.

 

[Tom.G]

Hmm, sounds interesting. Keep us posted as you can without giving away any secrets.

Tom

 

[Nik_2213]

I'm fairly sure Windows can handle two touch-screen enabled displays at once. Okay, you may have some trouble with drivers, you'll probably need a generic from the graphics card's chip maker rather than the gamer-optimised that's bundled...

I've no idea how you'd go about 'rolling your own' but it comes down to mapping the two small displays as one larger 'virtual'.

 

[Pat Geballa]

thanks again guys and will do tom