[sdiy] Resistive touch panels

[John Loffink]

To get two axis with a 4 wire touch panel, you have to inject ground and 
a voltage source on two pins and measure voltage across the other two, 
for each axis.  So you need a voltage source, some multiplexers and 
sample & holds at a minimum for a two axis controller.  You can get one 
axis of control just with voltages on two pins then measure across the 
others. 

This makes a nice little microcontroller project if you keep it simple.  
It can also be done with discrete circuitry.

-- 
John Loffink
The Microtonal Synthesis Web Site
http://www.microtonal-synthesis.com
The Wavemakers Synthesizer Web Site
http://www.wavemakers-synth.com


Ian Smith wrote:
> Hi all,
>
> Has anyone considered using resistive touch panels for control? like a joystick, if that's possible? Here's what I'm looking at:
> http://www.fujitsu.com/downloads/MICRO/fcai/touchpanels/4_wire_standard_ds_rohs.pdf
> It says that they have an x-axis resistance of 300 to 850 Ohms and a y-axis resistance of 100 to 600 Ohms. I don't know how useful that would be, but I keep thinking about the Korg Kaoss pad series. Can these be used by themselves or do they need special control circuits to use them the way I'm thinking of?
>
>