Hello.
How can I use reset pin in uno as a output pin.
Thanks.
Why do you want to ?
Run out of pins, maybe ?
yes I have run out all of my pins expect reset pin?
Is there any way to use this pin as output in arduino?
Is there any way to use this pin as output in arduino?
Not as far as I know.
What are you using all the pins for ?
If you are using an Arduino board then it is impossible I think because of how that pin is wired up on the board.
If you are using a bare chip and not an Arduino board then you can set the RSTDISBL fuse and it will allow you to use that pun as an io pin. But even then it works a little differently.
Refer to section 1.1.5 of the Holy Datasheet and the sections linked from there for more information.
The thread title mentions a Uno so probably not a bare chip. What I had in mind was using analogue pins as digital IO and/or using an analogue pin to read several input switches using a voltage divider.
Until we know what the OP is using the pins for we are in the dark.
Until we know what the OP is using the pins for we are in the dark.
When has that ever stopped us from proposing solutions?
Like multiplexing, maybe.
When has that ever stopped us from proposing solutions?
Hence my suggestions of using analogue pins as digital pins, which is often overlooked, and/or an analogue pin as a multi switch input.
When you set the fuse to disable the Reset feature (to allow the use of that pin for I/O) you disable all forms of serial programming, including ISP devices. Thus your first step should be to buy a High Voltage Rescue Shield: HV Rescue Shield 2 | MightyOhm This will allow you to reset your chip to factory fuse settings even with the Reset pin disabled.
Second step is to buy a USBasp or USBtinyISP so you can set the fuses. These cost under $5 through eBay but take a few weeks to arrive from China.
Each time you want to try your sketch:
Remove the ATmega328P from your Arduino UNO.
Plug it into the HV Rescue Shield on your OTHER Arduino UNO.
Reset it to factory settings.
Remove it from the HV Rescue Shield.
Plug it back into the Arduino UNO.
Connect the ISP device.
Burn an Arduino UNO bootloader.
Upload your sketch using the ISP.
Use AVRDUDE to manually set the RSTDISBL fuse.
Hi,
Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png?
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 tell us what your application is.
We may be able to help minimise your requirements for i/o pins.
Tom..... 
there's lots of tricks to connecting more parts to a uno then the amount of pins available most involve adding a few extra components (if you have really used all the pins). If you tell us what's connected (better still post a wiring diagram like tom suggested) we can tell you the easiest way to achieve what you need.