I found this website useful. http://www.handsetdetection.com/ It is free upto 10000 detection.
Sign up an follow the instruction to create your javascript. It will detect the visitor’s mobile and redirect to other website.
I created the following html and uploaded.
<!DOCTYPE html>
<html>
<head>
<script type='text/javascript' src='http://www.handsetdetection.com/sites/js/yournumber.js'></script>
</head>
<body>
<h1>You are accessing from a normal browser</h1>
</body>
</html>
Then you need to download Firefox addon called User Agent Switcher.
Also you need to download this text file and change the extension to xml and import to the User Agent Switcher.
You may find updated User Agent files in this forum.
Change your User Agent from Tools > Default User Agent to any mobile device and visit your website if it works.