Need a cheap touch sensor idea.. here it is

[ScaleRobotics]

First Question:

what I need to change in code to use PIC16F84A instead of current one ...

The 12F's have a GPIO port, most other chips have PORTA,PORTB etc. So that would have to be changed. Also your configs would have to be changed for the chip you are using. This is pretty much a topic of its own. Normally, one would look at the data sheet for the chip you are using, and see what settings would need to be applied to that chip. There is also no comparator on the 84, so you can comment that out.

Second Question:

what the code needed to make each touch of a sensor run a different device for example I

have 3 electric devices.

like Television and recorder and wash machine.

Touch Sensor1 = Run First Device if it OFF or OFF the first device if it ON.

Touch Sensor2 = Run Second Device if it OFF or OFF the Second device if it ON.

Touch Sensor3 = Run Third Device if it OFF or OFF the Third device if it ON.


and make the default condition for all devices is OFF.

Why don't you play with the code with some LED's and try for yourself?

Third Question:


Does I Need a Relay for Each Device Or can figure out a way without using it .. take in consideration these devices use AC 220 VOLT

I would like to take some time to point at some great advice Ioannis gave you above. Your work on 220 could kill you, or the equipment you make, could kill others.

Yes, you would need some large (pretty expensive) relays to run this kind of equipment.

Fourth Question:

Does the 3 copper plate sens the touch if I Cover them by one plate of Glass

or that will make a disruption so the touch will affect all of three sensors.

That mean it should be a different 3 plates of glass I Mean 1 Plate for each Copper Sensor for

avoiding disruption but this way will be very bad looking.

I know the capacitive touch sensors that are built into the newer chips (the 16F84 is one of the oldest most outdated chips around) does have the ability to sense over vinly, or through plexiglass. I am not sure Steve's cheap sensor idea has this capability, as I have never tried it. You could test it and see. If not, you may want to splurge, and spend $1.25 for one of the newer PIC chips with capacitive touch built in

As we always recommend, start out small. Blink an led. Then see if you can get Steve's code working on a chip to your liking. Once you figure out how to make it blink and LED, then think about how you might modify it to better fit your ideas.

But once again, working with 220 is very dangerous, and can kill your equipment, you, and others using your home made equipment.

And if you were looking for a cheap project, all the equipment you need to turn on and off these large amperage devices, will be rather expensive.

Here is his code edited for your chip. You will have to work on the configuration part though.

'   Few cents touch sensor
'   ======================
'   Using : Untested for PIC16F84A 
'    
'   Circuit is quite simple. One pin(GP4) is used as a signal generator.
'   This pin send signal to all "virtual push button" (GPIO<2:0>)
'   via 3 X 22K resistor. The touch sensor could be almost everything 
'   conductive.  
'
'   Once a sensor is touched, the program will blink a LED as follow
'                            PORTB.0 => 1 Blink
'                            PORTB.1 => 2 Blink
'                            PORTB.2 => 3 Blink


'   PIC config and programming mode
'   ===============================
    '
;    @ DEVICE  PIC12F629,INTRC_OSC_NOCLKOUT ' internal RC osc
;    @ DEVICE  PIC12F629,MCLR_OFF           ' Disable external MCLR
;    @ DEVICE  PIC12F629,WDT_OFF            ' Disable WatchDog timer
;    @ DEVICE  PIC12F629,PROTECT_OFF        ' Disable device protect
;    @ DEVICE  PIC12F629,CPD_OFF            ' Disable Code-Protect
 ;   @ DEVICE  PIC12F629,PWRT_ON            ' Enable Power-up timer
;    @ DEVICE  PIC12F629,BOD_ON             ' Enable Brown-out detect

'   I/O Alias definition
'   ====================
    '
    LED        VAR PORTB.5
    Generator  var PORTB.4
    
'   Hardware definition
'   ===================
    '                           
    TRISB = $0F ' PORTB<3:0> as input
                 ' PORTB<5:4> as output
                 '
;    CMCON  = 7   ' Disable internal comparator
    
'   Variable definition
'   ===================
    '
    Sensor var byte
    LOOP1   var byte

'   EEPROM assignement
'   ==================
    '
    data @3,3,0,2,1 ' table to convert 'Sensor' variable result to according
                    ' LED blink. See Result list bellow
    
'   Software/hardware initialisation
'   ================================
    '
    led = 0
    generator = 0
    
            
Start:
    ' /////////////////////////////////|\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
    ' /                              Start                                    \ 
    ' /////////////////////////////////|\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
    '
    ' Short explanation of the whole thing.
    '       1. Send a high level to all sensor input => PORTB<2:0>
    '       2. Read PORTB port 
    '       3. Send a low level to all sensor input
    '       4. Keep only PORTB<2:0> bits
    '       5. Test result
    '
    ' If no sensor has been touched, the result will be 7 => 0000 0111, case
    ' else, the body capacitance will introduce sufficient delay between
    ' step 1 and 2 wich will keep the according bit to 0.  
    '
    ' Results will be as follow
    '               NoSensor => 0000 0111 => 7
    '               PORTB.0   => 0000 0110 => 6
    '               PORTB.1   => 0000 0101 => 5
    '               PORTB.2   => 0000 0011 => 3
    '
    repeat
        Generator = 1       ' enable sensor power
        Sensor = PORTB       ' read sensor
        Generator = 0       ' disable sensor power
        Sensor = Sensor & 7 ' keep only Sensor bits
                            '        
        until Sensor != 7   ' redo the test untill one sensor is touch
    '
    ' Now we will flash an LED to confirm wich sensor has been touch
    '                      PORTB.0 => 1 Blink
    '                      PORTB.1 => 2 Blink
    '                      PORTB.2 => 3 Blink
    '
    read sensor,LOOP1 ' convert result to blink
    repeat
        LED = 1
        PAUSE 200
        lED = 0
        PAUSE 200
        LOOP1 = LOOP1 - 1
        until LOOP1 = 0

    goto start ' do it again...