16F726 Capacitive sensing module

[Ioannis]

Finally I got my first touch demo working with 16F1827 chip. The CSM module is easy to use and makes program small enough.

But, I have one problem with the stability of the output that shows whether one is touching, close to touch or not touching at all.

Although I have included Darrel's Average routine there is a grey region that makes deciding if one is touching not very clear.

The following test code has a LED indicator to show when touch pad is really touched or not. If finger is very close, value is playing up or down the threshold and makes the LED indicator blink.

OPTION_REG = %10000110    'Tmr0 from 256 presc and Int Clock
  
 T1CON = %11000001 '%00110000    ' TMR1 1:8 prescale, timer1 off

led         var portb.4       
value       var word
AvgCount CON 32  ' = Number of samples to average
FAspread CON 10000 ' = Fast Average threshold +/-
ADavg  VAR WORD
flag        var bit
'Interrupt Engine Setup
':::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
ASM
INT_LIST  macro    ; IntSource,     Label,      Type,       ResetFlag?
  INT_Handler   TMR0_INT,       _Timer_0,     PBP,    yes

 endm
 INT_CREATE               ; Creates the interrupt processor
    INT_ENABLE   TMR0_INT
ENDASM
':::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::       

goto main

Timer_0:
    t1con.0=0
    vALUE.lowbyte=tmr1l:VALUE.highbyte=tmr1h
    flag=1
    tmr1l=0:tmr1h=0
    t1con.0=1
@ INT_RETURN    

main:
clear
pause 1000

start:
if flag=1 then
    flag=0
    gosub Average
endif

hserout [27,"[H",27,"[10;0H","Value is: ",#vALUE," "]

if VALUE<319 then
    high led
else
    low led
endif
goto start

Average:
    IF Value = ADavg Then NoChange
    IF ABS (Value - ADavg) > FAspread OR Value < AvgCount Then FastAvg
    IF ABS (Value - ADavg) < AvgCount Then RealClose
    ADavg = ADavg - (ADavg/AvgCount)
    ADavg = ADavg + (Value/AvgCount)
    GoTo AVGok
  FastAvg:
    ADavg = Value
    GoTo AVGok
  RealClose:
    ADavg = ADavg - (ADavg/(AvgCount/4))
    ADavg = ADavg + (Value/(AvgCount/4))
  AVGok:
    Value = ADavg  ' Put Average back into Value
  NoChange:
Return

Any ideas welcome.
Ioannis