Hi!
i am upto something techy this summer. so i am curious_to_know the technical aspects of the capacitive touch screen- the actual capacitance developed, the minimum area of contact and/or the field required...that to if any.

i made some effort like "googling" but unfortunately got my hand only on the basic working principle without any such technical specifications

is anyone having such data?
also is any one aware of the the notion ink adam? any idea if it is using the projected capacitance or the surface capacitance.

ps: do not post links of wikipedia or howstuffworks ---the don't give the tech data i am looking for.

thanks
curious_to_know

 

You might get somewhere by looking up info on the IC's that do the sensing - http://www.cypress.com/?id=1575&source=header

 

thanks a lot for the link!

the specifications mention the circuit voltage requirements i am still unable to find the sensor capacitance requirements.

 

The sensor capacitance requirements differ from manufacturer to manufacturer, you will have to pick a Capacitive Touch IC and look up the specs on that, I have used the MPR084Q Capacitive touch sensor from Freescale Semiconductor, and there are others like it..... Microchip has Microcontrollers for Touch Sensing >>http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en548149

B. Morse

 

I did a PIC project with free HEX file that measures and displays capacitance down to 0.01pF in 0.01pF resolution;
http://www.romanblack.com/onesec/CapMeter.htm

It's ideal for working with capacitance sensors as you can connect it to your pad prototypes etc and read the change in capacitance from putting your finger near the pad. As an example putting my finger 10mm from a single wire increases the capacitance 0.05pF and my finger 5mm from the wire makes 0.10pF.

For working with capacitance sensors it really helps to have a high resolution sensitive capacitance meter. Check it out.