anyone ever tried this?

switching in fixed resistors on an analogue input to give more inputs. i.e. different resistors have different analogue values therefore wo can have loads of switches (inputs) on just one input pin?

Yes, and yes. hehe. Your referring to what's called a "ladder network" and was more common back in the days of analog computing than it is now, but still has a place. Namely just as you describe, 1 pin, many switches. The software overhead is a little bit more than for using digital I/O's, but you can theoretically have up to 1024 switches (or combinations) on a single pin.

--Andy P

It's easy, efficient &amp; easily extends - just set up suitable IF-THENs etc for the READADC return of the various R values. A convenient initial test layout uses a pot. or (better in my view) resistance box/wheel =&gt; <A href='http://www.dse.co.nz/cgi-bin/dse.storefront/4415d3fa01f2d2062741c0a87f9906d3/Product/View/Q1410 ' Target=_Blank>External Web Link</a>

and don't forget to consider what happens when two or more switches are pressed simultaneously!