That one will _not_ do the trick because its a hall "switch" the one I have used is a hall sensor the switch has on / off (digtal) action with some hysteresis however a hall "sensor" outputs an analog signal.
As for the magnet, I think that one is around the same size as mine but I think I have gone over the top. In my test I used a much smaller magnet which worked fine but since it was not a ring it came out of alignment if the top hat rotated around a bit. So the size for me was mostly dictated by the mechanics. However the size will also determine how far away the sensor will be able to pickup the field.
There is some more information in my links above and also in the link that Warwick (wazza187) posted.
Dean
Rockdude wrote:
That looks very cool!
That approach must be the most sturdy construction I've seen so far. I've got some questions for you since I want to try it as well
Will this Hall sensor work?:
http://www.electrokit.se/givare-o-se...latch_41003760
Data sheet for the Hall sensor:
http://www.electrokit.se/download/ATS177.pdf
How strong must the magnet be to work?
I've found one ring magnet with the dimensions 30x10x5mm Type N45 and strength 8,40kg.
Cheers
Martin