Hall Effect

Hi all,
I made a project some time ago that used reed switches to close circuits and light LEDs...very simple mechanical....beginner..etc, etc.

Thought it might be interesting to try to do the same but use the Arduino. I then read something about Hall Effect ensors and thought I could use these in place of Reed Switches to make the whole thing smaller?
....so I went to buy some Hall Effect Switches and found thousands (or so it seemed) of different types.

Any advice of a basic one to replace a reed switch? Just want to detect a magnetic field, don't need polatity or strength etc.

Many thanks!

This is a good one:-
http://uk.farnell.com/allegro-microsystems/a3214lua-t/hall-effect-switch-micropower-3sip/dp/1791389?in_merch=New%20Products&MER=i-9b10-00001144

I have used the Honeywell SS345PT. It looks very similar
to the one Grumpy_Mike suggested.

I have an example sketch at
http://wiblocks.luciani.org/docs/app-notes/pico1trc-hall-effect.html
Whenever the magnetic field changes a pin change interrupt
routine is called. When the main program detects a change
the time is read from the real-time clock and is output to the screen.

(* jcl *)


www: http://www.wiblocks.com
twitter: http://twitter.com/wiblocks
blog: http://luciani.org