scott wrote:
>> Again, my sat nav allows you to scroll like this - but it's very 
>> unpredictable. It doesn't "respond" very well to the touches you're 
>> trying to make. I don't know why. Also, it's very hard to *slide* 
>> warm, sticky fingers over a plastic surface in a smooth motion.
> 
> Your satnav is likely a resistive touch screen, it works when you 
> physically bend the top layer enough to make contact with the bottom 
> layer electrically, and then just like a variable resistor you can 
> measure the resistance to work out the position you touched.  The iPhone 
> uses a capacitive screen, as soon as you touch the surface of the screen 
> the electronics can detect the capacitance of your finger, also using 
> clever electronics/software it can work out the position of 2 fingers in 
> contact, to allow those wacky zoom and rotate operations.
> 
> The disadvantage of capacitive touch screens is that they only work with 
> your bare fingers, not while you are wearing gloves, or any sort of 
> stylus. The accuracy is also much lower than resistive touch screens, 
> but that doesn't really matter when you're using your fingers.

Damnit, I wish I knew some people IRL who possess such encyclopedic 
knowledge... I'd never be bored again!

[FWIW, the sat nav *does* in fact have a stylus. Unlike my dad's cheap 
device, the stylus is optional on mine. On my dad's, only the stylus 
will operate it...]

PS. Is it only me who things pointing a sharp pointy thing at a delicate 
and fragile layer of semi-liquid gloop fashioned into an intricate 
display mechanism is a bad idea?

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

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