Code for Touch Sensor

NWCCTV

Does anyone know of any code that will work with this sensor: http://www.ebay.com/itm/261758997611?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT ?

I purchased a few of them since they are so cheap and have a project in mind once the rest of my parts get here but I can not get the code in the OBEX http://obex.parallax.com/object/169 to work with it. Thanks for your help.

rosco_pc

NWCCTV wrote: »

... but I can not get the code in the OBEX http://obex.parallax.com/object/169 to work with it. Thanks for your help.

You just need to read the input pin.
Nothing more is needed, the logic in this object is to create a capacitive sensor with only the prop.
But in the module you bought that is handled by the touch sensor chip.

NWCCTV

Not sure I understand what you are saying. The way I read it is that when I place my finger near the sensor the LED on pin 16 should light up but it does not.

Hal Albach

Good Morning, Andy;
I believe what rosco_pc is trying to tell you is that you do not need a driver for this device. It senses the touch on its own and outputs a high to indicate the touch. Treat it like a push button

Duane Degn

Andy,

I haven't tested this with anything but based on rosco_pc and Hal's comments I figure it should work.

CON

  _clkmode = xtal1 + pll16x                           
  _xinfreq = 5_000_000

  TOUCH_PIN = 0

OBJ

  Pst : "Parallax Serial Terminal"

PUB Main

  Pst.Start(115_200)

  repeat
    Pst.Home
    result := ina[TOUCH_PIN]
    if result
      Pst.Str(string(11, 13, "Touched"))
    else
      Pst.Str(string(11, 13, "Not Touched"))

    Pst.ClearEnd
    Pst.Newline
    Pst.ClearBelow  ' clear any text below output
    waitcnt(clkfreq / 20 + cnt)

Those sensors look pretty cool. It looks like you can power them with 3.3V.

If for some reason you power them with 5V you'll need a series resistor between the sensor's output and the Propeller's I/O pin. I'd use something between 3.3k ohm and 10k ohm. Again this is only if using 5V on the sensor's VDD pin. If you use 3.3V you don't need a resistor but a 100 ohm resistor would keep the Prop safe in case there was a code error which set the I/O pin as an output.

Edit: I had left out "+ cnt" in the waitcnt command.

NWCCTV

Well, The PST shows Not Touched when I am not touching but does not show Touched when I touch it.

EDIT: However, I was able to get it to work just like a push button. You are correct, these things are kind of cool and pretty cheap too!!!!.

Thanks all for contributing. Now on to my project!!

Duane Degn

Sorry, I left out the "+ cnt" part in the waitcnt command. I just edited the earlier post. It should work now.

NWCCTV

Yep. It sure does. I thank you very much. I basically just needed to get it to work as a standard push button, which from what I am reading is what it is!!