i want to know how i can make a programmable button (with delay) to pin(RESET) in arduino to reset the board (i have tried with a timer555 but i can't change the delay of ).
thx 
What exactly are you trying to do?
And why are you doing it with a 555?
i need to reset the board arduino in a specific time(10s) i have connected the RESET pin with other pin in arduino but that's not working so i need a method with external button to reset arduino in (10s)
try giving a little more verbose description of your intended task. like, when do you want to reset. are you saying that if you hit a button you want reset held low for ten seconds, or you want a reset every ten seconds. somewhat confusing.....
Why do you want to reset every 10 seconds? It probably won't do what you want.
My initial impression is that this is a classic XY problem.
Either that or he wants a delayed software-triggered reset and doesn't know about the WDT?
Why not just use blink without delay style code and execute whatever you're doing every 10 seconds?
i want to Get reset my board arduino evry(10s) with reset pin and without push button,
MAK93:
i want to Get reset my board arduino evry(10s) with reset pin and without push button,
Why on earth do you want to do that?! That's a bizzare thing to want to do.
And it has to be with the reset pin, not the WDT?
What are you really trying to do? Resetting the Arduino is a means to an end...
MAK93:
i want to Get reset my board arduino evry(10s) with reset pin and without push button,
Why?
As suggested, there are ways to restart code which does not require a hardware reset.
.
Hi,
If all you want to do is have your arduino do a 10second cycle, then it can be done with software, no need to restart the UNO to repeat the process.
Can you please post a copy of your sketch, using code tags?
They are made with the </> icon in the reply Menu.
See section 7 http://forum.arduino.cc/index.php/topic,148850.0.html
Also an explanation of your complete project, what are you trying to do and with what?
Thanks.. Tom... 
MAK93 - you do not want your board reset every 10 seconds.
What you want is for the stuff that is currently in your setup() to be executed once every 10 seconds.
See xyproblem.info.
MAK93:
i want to Get reset my board arduino evry(10s) with reset pin and without push button,
No you don't. That is just silly.
Now explain what you really want to do, not how you think you will achieve it.
As you are already aware, it is an odd request, especially a 10 second cycle.
Because an unstable RF component, as a work around, I once wanted a restart every 24 Hours, so I used a transistor, controlled by an pin, to pull the reset pin low. (standard NPN General purpose say BC547B. Collector to Reset pin, emitter to ground, base, via say a 1K resistor to a selected Arduino pin.). When the selected pin is set HIGH, the Arduino will reset.
6v6gt:
As you are already aware, it is an odd request, especially a 10 second cycle.
Because an unstable RF component, as a work around, I once wanted a restart every 24 Hours, so I used a transistor, controlled by an pin, to pull the reset pin low. (standard NPN General purpose say BC547B. Collector to Reset pin, emitter to ground, base, via say a 1K resistor to a selected Arduino pin.). When the selected pin is set HIGH, the Arduino will reset.
The data sheet specifically cautions against this, it doesn't ensure a proper reset
6v6gt:
As you are already aware, it is an odd request, especially a 10 second cycle.
Because an unstable RF component, as a work around, I once wanted a restart every 24 Hours, so I used a transistor, controlled by an pin, to pull the reset pin low. (standard NPN General purpose say BC547B. Collector to Reset pin, emitter to ground, base, via say a 1K resistor to a selected Arduino pin.). When the selected pin is set HIGH, the Arduino will reset.
I can't see why that was any reason to reset the Arduino. Why not just reset the "unstable RF component". You should have used the watchdog timer if you really wanted to reset the Arduino. There is simply no need to reset the Arduino and if you think there is then there is something you are not understanding.
Grumpy_Mike:
I can't see why that was any reason to reset the Arduino. Why not just reset the "unstable RF component". You should have used the watchdog timer if you really wanted to reset the Arduino. There is simply no need to reset the Arduino and if you think there is then there is something you are not understanding.
OK. I don't claim it was a perfect solution. Anyway, here is a tested sample to illustrate using the Watchdog timer to perform such a reset.
#include <avr/sleep.h>
#include <avr/wdt.h>
void setup() {
Serial.begin(9600) ;
Serial.println("starting. . . ") ;
delay (5000) ;
WDT_Init() ;
}
void WDT_Init(void)
{
//see http://www.embedds.com/using-watchdog-timer-in-your-projects/
//disable interrupts
cli();
//reset watchdog
wdt_reset();
//set up WDT interrupt
WDTCSR = (1<<WDCE)|(1<<WDE);
//Start watchdog timer with 4s prescaler
WDTCSR = (1<<WDE)|(1<<WDP3);
//Enable global interrupts
sei();
}
void loop() { }