8 replies to this topic

[anita_p]

Hello,

I am trying to write a program for pollling of two push buttons. My main requirements are : the two buttons should be pressed together for 1s. For simple button polling, I wrote this

while(1)
{
  if(BUTTON_1 & BUTTON_2)
     LED_ON();
}

But how can I add 1s condition?

Please suggest ?

Thnxs
Anita

Edited by Jaan, 08 September 2009 - 12:22 PM.
Please use code tags when you are posting your codes!

[Aereshaa]

do this:

timer = 0;
while(0){
if(button1 && button2)timer = time(0);//begin count
else timer = 0;//the user stopped pressing!
if(timer+1 == time(0))led_on();//user pressed for one second.
}

[anita_p]

Thank you for the suggestion and example code.

But what if I dont have timer?

[theonejb]

As a very inefficient and rather lame technique, calibrate a for loop, like so:

while(1)

{

  if(BUTTON_1 & BUTTON_2) {

    for(int i = 0; i < ONESECINT; i++);

    if(BUTTON_1 & BUTTON_2)

       LED_ON();

  }

}

Try different values for ONESECINT until you have a good approximate 1s interval.

[dargueta]

That won't always work. It will definitely vary from machine to machine, and even on the same machine when different programs are running, the same programs are doing different things, etc.

anita_p, you definitely should have time.h, because it's part of the standard C library. If not, you have a serious problem.

Edited by dargueta, 08 September 2009 - 05:48 PM.

[dcs]

dargueta said:

anita_p, you definitely should have timer.h, because it's part of the standard C library. If not, you have a serious problem.

Which standard are you using? :p

[edit]Alright. I need to try to quit nitpicking for a while.

[edit=2]To the OP: what platform is this on?

[dargueta]

Sorry, I meant time.h (note the lack of r). Edited in previous post.

[kiddies]

hey man...give me a complete c code from it...i wanna lear n try....thanks before

[dargueta]

I'd say it's pretty platform-dependent - what system do you want it for? I would imagine that you might be able to use ncurses for this, which would make it portable. However, I've never used the library myself, so I don't know if they support key event capture. Anyone else know?