Some PHP functions to detect if a UA is mobile/tablet

mobile_detection.php

<?php
/**
 * Inspired by the neat Browser Gem for Ruby: https://github.com/fnando/browser
 * 
 * Copyright (c) 2014 Daniel Sager
 * License: https://gist.github.com/dsager/0edcbf806b5b86e78455#file-2014
 */

/**
 * @param null|string $ua
 * @return bool
 */
function is_tablet($ua = null) {
  if (is_null($ua)) $ua = strtolower($_SERVER['HTTP_USER_AGENT']);
  if (preg_match('/ipad/', $ua)) return true;
  if (preg_match('/touch/', $ua) && preg_match('/windows nt 6.[2-3]/', $ua) && preg_match('/arm/', $ua)) return true;
  if (!is_phone($ua) && preg_match('/android/', $ua) && !preg_match('/opera|opr/', $ua)) return true;
  if (preg_match('/playbook/', $ua) && preg_match('/rim tablet/', $ua)) return true;
  return false;
}

/**
 * @param null|string $ua
 * @return bool
 */
function is_phone($ua = null) {
  if (is_null($ua)) $ua = strtolower($_SERVER['HTTP_USER_AGENT']);
  if (preg_match('/opera mini/', $ua)) return true;
  if (preg_match('/blackberry/', $ua)) return true;
  if (preg_match('/(mobi(le)?|symbian|midp|windows ce|windows phone)/', $ua)) return true;
  if (preg_match('/(psp|playstation vita)/', $ua)) return true;
  return false;
}