Capacitive Touch Button by using ADC channel (the CVD system)

[sumityadav]

yeah....sorry for that...i am new here....i am an B.TECH final year student.....i am trying to work on touch technology myself....
this is my circuit diagram in proteius. i tried by burning the code in this but i do not know about the exact digital value after a touch is made
and one more thing when we talk about the actual hardware i studied that the touch sensor is connected to one or more adc channel. the second channel is continuously scanning and connected to vdd or ground untill the touch is mot made through first one.......can u please explain how?????

[igeorge]

Hello Norm,
I tried your example code, but maybe i did something wrong because it did not work
First i understood that you use an array , size 100 to store the readings. Is this array of words or bytes ?
Reading the pic18f87j90 data sheet the ADRESH it is a byte, but the whole analog reading it is a word.
Do you store just the high byte of the conversion ?
Do you also have a schematics to look at it ?
I do not know if i have to leave PortA.2 floating or i have to connect it to something aka VDD or vss
What is the clock frequency of your CPU ? Do you run internal or from a crystal ?
I love to try it and make it work on my PIC18F87J90.
Thank you
Ion

[Art]

Did this years ago with the POT command and any digital I/O pin.



Worked perfect, but the POT command will slow down a cyclic program.

[igeorge]

Thank you Art
I will try it