你可以在GitHub上查看GBDeviceInfo，也可以通过CocoaPods获得。它提供了简单的API来检测各种属性，支持所有最新的设备:

设备的家庭

[GBDeviceInfo deviceDetails]。family == GBDeviceFamilyiPhone;

设备模型

[GBDeviceInfo deviceDetails]。model == GBDeviceModeliPhone6。

欲了解更多，请参阅Readme。

你可以像这样使用UIDevice类:

NSString *deviceType = [UIDevice currentDevice].model;

if([deviceType isEqualToString:@"iPhone"])
    // it's an iPhone

我喜欢埃里卡·萨顿的作品。她包括苹果电视设备和其他你可能想不到的设备。

https://github.com/erica/uidevice-extension/blob/master/UIDevice-Hardware.h

要识别iPhone 4S，只需检查以下内容:

var isIphone4S: Bool {

    let width = UIScreen.main.bounds.size.width
    let height = UIScreen.main.bounds.size.height
    let proportions = width > height ? width / height : height / width

    return proportions == 1.5 && UIDevice.current.model == "iPhone"
}

NSString *deviceType = [[UIDevice currentDevice] systemName];

我可以保证，上述建议将适用于iOS 7及以上版本。我相信iOS 6也能运行。但我不确定。

基于以上非常好的答案，以下是我想到的。这与@Rodrigo的回答非常相似，但解决了@Oliver对该回答的评论所关注的问题。这还提供了在输出字符串中包含模型字符串的选项。

+ (NSString *) deviceModel {
    size_t size;
    sysctlbyname("hw.machine", NULL, &size, NULL, 0);
    char *model = malloc(size);
    sysctlbyname("hw.machine", model, &size, NULL, 0);
    NSString *deviceModel = [NSString stringWithCString:model encoding:NSUTF8StringEncoding];
    free(model);      

    return deviceModel;
}

+ (NSString *) deviceName {
    NSString *deviceModel = [DeviceGateway deviceModel];                    

    if ([deviceModel isEqual:@"i386"])      return @"Simulator";  //iPhone Simulator
    if ([deviceModel isEqual:@"iPhone1,1"]) return @"iPhone1G";   //iPhone 1G
    if ([deviceModel isEqual:@"iPhone1,2"]) return @"iPhone3G";   //iPhone 3G
    if ([deviceModel isEqual:@"iPhone2,1"]) return @"iPhone3GS";  //iPhone 3GS
    if ([deviceModel isEqual:@"iPhone3,1"]) return @"iPhone4";    //iPhone 4 - AT&T
    if ([deviceModel isEqual:@"iPhone3,2"]) return @"iPhone4";    //iPhone 4 - Other carrier
    if ([deviceModel isEqual:@"iPhone3,3"]) return @"iPhone4";    //iPhone 4 - Other carrier
    if ([deviceModel isEqual:@"iPhone4,1"]) return @"iPhone4S";   //iPhone 4S
    if ([deviceModel isEqual:@"iPod1,1"])   return @"iPod1stGen"; //iPod Touch 1G
    if ([deviceModel isEqual:@"iPod2,1"])   return @"iPod2ndGen"; //iPod Touch 2G
    if ([deviceModel isEqual:@"iPod3,1"])   return @"iPod3rdGen"; //iPod Touch 3G
    if ([deviceModel isEqual:@"iPod4,1"])   return @"iPod4thGen"; //iPod Touch 4G
    if ([deviceModel isEqual:@"iPad1,1"])   return @"iPadWiFi";   //iPad Wifi
    if ([deviceModel isEqual:@"iPad1,2"])   return @"iPad3G";     //iPad 3G
    if ([deviceModel isEqual:@"iPad2,1"])   return @"iPad2";      //iPad 2 (WiFi)
    if ([deviceModel isEqual:@"iPad2,2"])   return @"iPad2";      //iPad 2 (GSM)
    if ([deviceModel isEqual:@"iPad2,3"])   return @"iPad2";      //iPad 2 (CDMA)

    NSString *aux = [[deviceModel componentsSeparatedByString:@","] objectAtIndex:0];

    //If a newer version exists
    if ([aux rangeOfString:@"iPhone"].location != NSNotFound) {
        int version = [[aux stringByReplacingOccurrencesOfString:@"iPhone" withString:@""] intValue];
        if (version == 3) return @"iPhone4";
        if (version == 4) return @"iPhone4s";
        return @"Newer iPhone";
    }
    if ([aux rangeOfString:@"iPod"].location != NSNotFound) {
        int version = [[aux stringByReplacingOccurrencesOfString:@"iPod" withString:@""] intValue];
        if (version == 4) return @"iPod4thGen";
        return @"Newer iPod";
    }
    if ([aux rangeOfString:@"iPad"].location != NSNotFound) {
        int version = [[aux stringByReplacingOccurrencesOfString:@"iPad" withString:@""] intValue];
        if (version == 1) return @"iPad3G";
        if (version == 2) return @"iPad2";
        return @"Newer iPad";
    }

    //If none was found, send the original string
    return deviceModel;
}

+ (NSString *) deviceNameWithDeviceModel:(BOOL)shouldIncludeDeviceModel {
    if (shouldIncludeDeviceModel) {
        return [NSString stringWithFormat:@"%@ (%@)", [DeviceGateway deviceName], [DeviceGateway deviceModel]];
    }

    return [DeviceGateway deviceName];
}