How can I differentiate between smart phones and others?

I'm looking to revamp our mobile site with something simple for phones below the ambiguous smart phone category and something a little more interesting for the phones above this category. I'm not interested in WAP/WML for this project. I'm building a ASP.Net 4 MCV 2 app and using MBDF

What I'd like to know is how best to define this differentiation when using MBDF? Screen size, Javascript, SpportsTouchScreen etc. are all in MBDF along with others but I'm not sure where to draw the line and where the data is most accurate for the broad number of devices.

What do those of you out there developing for this spread of hardware & software split on?

Thanks, Denis

P.S. I've done 开发者_开发知识库my research on xHTML MP1.0 - 1.2 and the best practises for implementation to ensure broad coverage but I don't want to restrict the newer phones out there to what the base line can see.

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I personally use simple mobile browser dedection script and limit max screen width to 240px. I also use simple AJAX and JavaScript calls too.

Above setup works fine for 90% of my visitors but my sites aren't business critical sites.

You can try http://wurfl.sourceforge.net/ but .net api is not as good as PHP one

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So after a bit of testing myself I think I'm going to stick with testing if they support JavaScript and Touch using the MBDF. This line in the sand isn't perfect but it seems like the best out there to me.

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Here is a neat little tutorial on Browser Detection using JavaScript

Browser Detection