Detect iOS device type

you can easly detect iphone, iphone5 and iPad with below condition (But not iTouch! iTouch is treated as if it were an iPhone with this code!):-

 if([[UIDevice currentDevice]userInterfaceIdiom]==UIUserInterfaceIdiomPhone)
 {
     if ([[UIScreen mainScreen] bounds].size.height == 568)
     {


     }
     else
     {
         //iphone 3.5 inch screen
     }
 }
 else
 {
        //[ipad]
 }

UPDATE

You can also use MACRO or define Variable for check is that iPhone5,iPhone4 or iPad like Bellow:-

#define isiPhone5  ([[UIScreen mainScreen] bounds].size.height == 568)?TRUE:FALSE
#define isiPhone  (UI_USER_INTERFACE_IDIOM() == 0)?TRUE:FALSE

Example:-

if(isiPhone)
     {
         if (isiPhone5)
         {


         }
         else
         {
             //iphone 3.5 inch screen
         }
     }
     else
     {
            //[ipad]
     }