http://mobiledetect.net/ servisini kullanarak yapabilirsin.

örnek kullanimi asagidaki gibi.

//include the file
require_once 'Mobile_Detect.php';
$detect = new Mobile_Detect;

// Any mobile device (phones or tablets).
if ( $detect->isMobile() ) {
 //do some code
}

// Any tablet device.
if( $detect->isTablet() ){
 //do some code
}