homework board acting weird (very weird)

blink13

PLEASE help me i tried doing a program that when a button was pushed a light would turn on· and off but whenever my finger gets close to the button the light turns on. This is·with out even touching the button. If how ever i do touch the button (not press it) the light will turn on and stay on untill i touch(not press) the button again this is conflicting with my programming and i dont know wearhter its workin or not please help.
heres my program:

'{$STAMP BS2}
'{$PBASIC 2.5}
DO
IF (IN3 = 1)THEN
·· HIGH 14
ENDIF
·IF (IN3 = 0)THEN
·LOW 14

· ENDIF
LOOP

allanlane5

I'm guessing you don't have a pull-up OR pull-down on your pin 3. Thus it is acting as an antenna. The closeness of your finger is enough to change the noise pattern to a one or zero.

You need a pull-up resistor (10 Kohms to 25 Kohms) to give your pin 3 a value, when the button is not pressed.

Jon Williams

Allan is right, you need a pull-up or pull-down on any input.· In your case you could simplify your program by using an active-high input:



... then·write your code like this:

' {$STAMP BS2} 
' {$PBASIC 2.5} 

Trigger     PIN    3 
Solenoid    PIN    4 

Reset: 
  LOW Solenoid     ' make output low 

Main: 
  DO 
    Solenoid = Trigger 
  LOOP 
  END

I suspect that you're going to add additional logic to your program -- because as it is you don't need a microcontroller; simply connect the trigger to the solenoid.


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Jon Williams
Applications Engineer, Parallax
Dallas, TX· USA

blink13

oh yeh im going to add other firing modes but thanks

blink13

ohh i had a few resistors set up like that now it woks thanx

blink13

oh yeh and what could i do so that when the button is pushed it turns on and off the output or the solenoid to achieve full auto i cant get anything to work

Jon Williams

Perhaps you ought to back up a step ... our book "What's A Microcontroller?" is a great introduction to BASIC Stamp programming.· After you spend some time with WAM, you'd come up with a program like the update I made below:

' {$STAMP BS2} 
' {$PBASIC 2.5} 

Trigger     PIN    3 
Solenoid    PIN    4 

IsOn        CON    1 
IsOff       CON    0 

Reset: 
  LOW Solenoid     ' make output low 

Main: 
  DO WHILE (Trigger = IsOn) 
    Solenoid = IsOn 
    PAUSE 100 
    Solenoid = IsOff 
    PAUSE 100 
  LOOP 
  END

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Jon Williams
Applications Engineer, Parallax
Dallas, TX· USA

Post Edited (Jon Williams) : 1/30/2005 1:34:11 AM GMT

blink13

i actually have that book becuase i baught the homework board. I have been doint the projects in it but i kinda skip around.