This is function check type device

UIDevice-Platfform

#include <sys/types.h>
#include <sys/sysctl.h>

@interface UIDevice(Hardware)

- (NSString *) platform;

- (BOOL)hasRetinaDisplay;

- (BOOL)hasMultitasking;

- (BOOL)hasCamera;

@end

@implementation UIDevice(Hardware)

- (NSString *) platform{
    int mib[2];
size_t len;
char *machine;

mib[0] = CTL_HW;
mib[1] = HW_MACHINE;
sysctl(mib, 2, NULL, &len, NULL, 0);
machine = malloc(len);
sysctl(mib, 2, machine, &len, NULL, 0);

    NSString *platform = [NSString stringWithCString:machine encoding:NSASCIIStringEncoding];
    free(machine);
return platform;
}

- (BOOL)hasRetinaDisplay {
    NSString *platform = [self platform];
    BOOL ret = YES;
    if ([platform isEqualToString:@"iPhone1,1"]) {
        ret = NO;
    }
    else
        if ([platform isEqualToString:@"iPhone1,2"])    ret = NO;
    else 
        if ([platform isEqualToString:@"iPhone2,1"])    ret = NO;
    else 
        if ([platform isEqualToString:@"iPod1,1"])      ret = NO;
    else
        if ([platform isEqualToString:@"iPod2,1"])      ret = NO;
    else
        if ([platform isEqualToString:@"iPod3,1"])      ret = NO;
    return ret;
}

- (BOOL)hasMultitasking {
    if ([self respondsToSelector:@selector(isMultitaskingSupported)]) {
        return [self isMultitaskingSupported];
    }
    return NO;
}

- (BOOL)hasCamera {
   BOOL ret = NO;
   // check camera availability
   return ret;
}

@end

//Example how use : 
NSLog(@"platform %@, retita %@, multitasking %@", [[UIDevice currentDevice] platform], [[UIDevice currentDevice] hasRetinaDisplay] ? @"YES" : @"NO" , [[UIDevice currentDevice] hasMultitasking] ? @"YES" : @"NO");