Small Spring Wobble Swtich

Hi

Anyone know where to get a switch like this one:

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Imgur

Thanks!

Cameron

Try searching for "Cat whisker micro switch". Here's an example

http://www.grainger.com/Grainger/SQUARE-D-Limit-Switch-2UYP2

Although this is an industrial version and way over kill for what you seem to need.


Rob

You could always build one yourself from some steel wire...

@cr0sh- I tried building a unit last night with a spring (not sure what type of metal) and a straightened out standard office paperclip. It worked sometimes but with varied success. A few times it would make the connection but the LED wouldn’t light up. I think your suggestion of using steel is a good one, maybe a thicker nail should replace the paperclip and I should find a tighter wound spring. Thoughts?

See the Flickr image link. http://www.flickr.com/photos/command_z/6222981916/

@Graynomad- Thanks, but yes those are too big for what I need.

command_z: @cr0sh- I tried building a unit last night with a spring (not sure what type of metal) and a straightened out standard office paperclip. It worked sometimes but with varied success. A few times it would make the connection but the LED wouldn't light up. I think your suggestion of using steel is a good one, maybe a thicker nail should replace the paperclip and I should find a tighter wound spring. Thoughts?

Well - more turns per inch (or cm, whatever your unit of pref) could help, but you also (may) want to have a spring that has steel with less tension (I'm not sure what the technical term is - ductility?). Springs work because they use a special formulation of steel called - surprisingly - spring steel:

http://en.wikipedia.org/wiki/Spring_steel

You can purchase spring steel in wire form to make your own springs (if you have the tools) - gauge of the wire will also affect how "springy" it is, so keep that in mind as well.

You might want to try sanding/polishing the inside of the spring and your paperclip/nail to make sure that contact is good. You might also want to try to electroplate the spring and nail with copper to increase conductivity (plenty of info on the net about how to do this - its fairly easy, although be aware that you have to use a poisonous chemical in the process - copper sulfate).

Another thing is that you might want to use an interrupt to detect the switch closure, and not polling - polling might miss the event (depending on how brief the contact is), whereas using a pin-change interrupt might pick up the closure of the contacts better.

Hope this helps...

:)

You can purchase spring steel in wire form to make your own springs

I have made a few from old steel guitar strings 8)

There are excellent springs in old (or new) ballpoint pens