28 Jul 2007 jkkroll   » (Master)

Which switch is which?

I haven’t been working on the Pocketwatch much because I am waiting for the display, and I have been rather nervous about constructing the encoder/switch with my limited mechanical abilities. But tonight I was putting off starting the last Harry Potter book (Don’t tell me! I haven’t read it yet! *fingers in ears* NAH NAH NAH) and I decided to head into the lab and fiddle around. I ended up picking up the pocketwatch and constructing the switch mechanism. It actually turned out rather well, nice and smooth, not wobbly. It still needs finishing, but here it is:

switch1 Switch2

The tiny disc magnet is glued into a slot in the plastic shaft on the left. The bushing is made from a drilled out and turned down 2-56 nylon standoff. Pressing down on the shaft engages the tactile switch with a satisfying *CLICK* and spinning the shaft will cause the hall effect sensors to sense the rotation.

The encoder started as a sketch:

encoder1

Then someone on the Steampunk Tactile forum suggested using one magnet and two hall sensors. Great idea! I built up a demo to try it out:

http://www.robotguy.net/tn_pw_encoder_test.jpg http://www.robotguy.net/tn_pw_encoder_test2.jpg

Lo and behold, it works!

Syndicated 2007-07-28 06:49:10 from robotguy.net/Blog

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