X,Y coordinate touchpad using capsense mpr121 chip

[plasmaninjaa]

X,Y coordinate touchpad with cap sensor

Hey guys. I have ordered the MPR121 on a breakout board from sparkfun.
It is a I2c capsensing chip with 12 capsensing pins.
I am working on a project which will need to use a touch pad to work.
Basically I will be printing out this color circle: http://imgur.com/uu9eep4
it will have a radius of 2 inches.

I am hoping to have it control rgb leds (obviously whatever color your finger is on, the rgb leds change to)
but i have one problem... I have absolutely zero idea where to start or what to do now!

I have made touch sensors before, even scroll wheels that use 3 touch sense pins... but I have no idea how i would design a touch pad, and what the sensors will look like (i.e. shapes) and what the code would be like.

I know i have 12 touch sensor pins at my disposal with this chip, but I need many of those other ones for other buttons, so i need to use as few of those pins as possible.

Please let me know if you have any advise on how even start this project!

I would really appreciate it

 

[westaust55]

Step 1. Try a google search for mpr121 capacitive touch keypadpad.
from here:http://www.google.com.au/search?hl=e...ed=0CD8Q1QIoAA
I see a YouTube demo and several posts on the topic including images for PCB keypads.Tutortials for conenction to Arduino and XBee modules.

Step 2. Experiment. Use a breadboard and proto-type some circuits.

 

[AllyCat]

Hi,

Note that three LEDs can display (at best) only the colours within a "colour triangle", not a full circle. There is a lot of useful information concerning LED colours and behaviour in the .PDF attached to post #9 of this recent thread.

Cheers, Alan.