Triggering a reed switch at a distance...

starhawk

[H]F Junkie
Joined
Oct 4, 2004
Messages
8,908
Making an electronic puzzle as a birthday present for a friend who is not on [H] ;)

I have a "reed switch" (I use that term loosely, it's not even encapsulated) from a Dollar Tree window alarm. I can trigger it if I get a hard drive voice-coil magnet real real close -- but I need to trigger it through a piece of cheap wood (I suspect it's balsa) about 3/8" thick...

How do I do that, on the super-cheap and without ordering from China?
 

TED

Gawd
Joined
Oct 21, 2002
Messages
746
Try a neodymium magnet. If it wont work alone then stick one on the switch and use the polar opposite to actuate it. Take apart an old busted HDD for them.
 

starhawk

[H]F Junkie
Joined
Oct 4, 2004
Messages
8,908
SOLVED in a really ghetto way.

I'll just say for now that it involves stove bolts and their corresponding nuts and washers from a hardware assortment... and a dollar store zip tie :D
 

Mohonri

Supreme [H]ardness
Joined
Jul 29, 2005
Messages
5,751
I was gonna say you need something to contain the magnetic field through the wood. So drill a hole from the inside of the wood *almost* all the way through, and fill it with a piece of steel or other magnetically-permeable substance. Mount the reed switch on the inside of the wood on top of the metal. That way, the magnetic fields will get through to the reed switch.
 

starhawk

[H]F Junkie
Joined
Oct 4, 2004
Messages
8,908
Update... found a real reed switch, worked great -- but a different part of the puzzle box didn't. So it's on the list of things for me to rebuild when I have the chance in a week or two. (I've got another project in front of it...) Should be interesting...
 
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