RE: Contact sensors?

["Paul Gordon" <paul@xxxxxxxxxxxxxxxxxxxxx>]

Hell yeah!!!

I dismantled a couple of old hard disks several years ago to retrieve
the magnets, - I still have (and use) them...

They are *the strongest* magnets I have ever seen! - SWMBO absolutely
cannot pull one off the fridge door without mechanical assistance, -
i.e. if it's holding something to the fridge (like a fairly thick
calendar) then she can exert enough force by getting a good handful of
calendar & pulling on that, - but if the magnet is just stuck there
with
nothing under it, the only way she's able to remove it is by sliding it
across to the edge of the door and sliding it right off the side.

Two of them will leap at each other (very vigorously!) from quite a
distance, - probably about 50-70mm - with such force it's like
arkwright's till - you don't want to have your fingers in between when
they snap together! When 2 are stuck together, even I can't easily pry
them apart & usually have to slide them apart sideways.

I use them for holding thick or heavy things to the fridge that no other
"proper" fridge magnet would stand a chance of coping with.

Paul G.

> -----Original Message-----
> From: ukha_d@xxxxxxx [mailto:ukha_d@xxxxxxx] On Behalf
Of
> Rob Iles
> Sent: 20 November 2008 05:44
> To: UKHA Group
> Subject: Re: [ukha_d] Contact sensors?
>
> Reed switch + rare earth magnets? I've got a couple salvaged from an
old
> HDD, and trust me - they're very strong! - can easily imagine them
closing
> a
> reed switch at 50-70 mm!
>
> Apologies in advance if I've missed the point!
>
> R.
>
>
> 2008/11/19 Paul Gale <groups2@xxxxxxx>
>
> >   Hi pete,


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