hacked a touchscreen//need to debounce, de-jitter

Using Arduino Sensors
1

Hi

novice programmer would very much welcome tips on how to 'de-jitter' noisy touch panel voltages:

using a stylus gives clean sharp repeatable voltages (I'm using the standard circuit for hacking these: pwr/gnd to one axis pair, read from one of the other, then invert and repeat for the other axis); using a finger causes 'ramp up' on contact, 'ramp down' on release. ie can someone recommend a method for averaging that isn't too slow. Here's my code

/* TOUCHSCREEN ELECTRODE PAIRS= X1-X2, Y1-Y2
connect as A0=X1, A1=Y1, A2=X2, A3=Y2; 
A0 and A1 alternate readings, so 1k pulldown to gnd on these;
'open circuit' floating values cured via digitalWrite to 0v on
A2 and A3
*/
int xVal = 0;
int yVal = 0;

void setup()
{
Serial.begin(9600);
}

void loop()//first axis cycle
{
pinMode(A0, OUTPUT); 	//analog 0 = gnd; 			
pinMode(A2, OUTPUT);	//analog 2 = +5v;
pinMode(A1, INPUT);	//analog 1 = signalRead; 		
pinMode(A3, INPUT);	//switch3			

digitalWrite(A0, LOW);	//gnd
digitalWrite(A2, HIGH);	//+5v

delay(5);		//let voltage settle
xVal = analogRead(A1);	//read pin 1
xVal/=4;                //0-1024 = 0-128
digitalWrite(A2, LOW);  //back to gnd

//switch pinModes to read other axis
pinMode(A3, OUTPUT);	//analog 3 = +5v
pinMode(A1, OUTPUT);	//analog 1 = gnd
pinMode(A2, INPUT);	//switch2
pinMode(A0, INPUT);	//analog 0 = signalRead

digitalWrite(A1, LOW);	//gnd
digitalWrite(A3, HIGH);	//+5v
delay(5);
yVal = analogRead(A0);
yVal/=4;
digitalWrite(A3, LOW);  //back to gnd

//either monitor, or send to Max
//Serial.print("X= ");
Serial.print(xVal,BYTE);
//Serial.print("\t\tY= ");
Serial.print(yVal,BYTE);
Serial.print(255, BYTE);
delay (40);
}

n00bmeister
ps, can I get email notifications on this forum somehow?