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Arduino controlled Dimmer Switch by asp55 is licensed under the Attribution - Share Alike - Creative Commons license.
© 2009 by asp55
Instructions
What you need:
Material (Rough sizes, you could probably compact the parts some)
4" x 7" 16th inch acrylic x2
7" x 11" 8th inch acrylic x1
Fasteners
3/8" #0 machine screw x2
1/2" #6-32 bolts x9
#6-32 nuts x 4
1" #4-40 bolts x4
#4-40 nuts x4
Other Hardware:
NEMA compliant Rotary Dimmer Switch x1
NEMA compliant Outlet x1
Power cord x1
3 gang junction box x1
Dirty Rubber band x1
Electronics
HS-322HD Servo x/ small wheel horn x1
(Oh, and an arduino and wall wart for good measure)
Inside the 3 gang box wire up your outlet and dimmer switch to your electric plug , match the colors, it's fairly simple. I broke the connection between the top and bottom socket out the outlet so that the top outlet could power the arduino + servo while the bottom was operated by dimmer.
Cut your pieces. Face plates from 1/16th inch acrylic, pulley bits from 1/8th.
Fasten the two faceplate layers to your junction box, the bottom layer has larger holes to give all the hardware's raised parts clearance. In the smaller holes use the #6 bolts (NEMA standard)
Laminate the smaller pulley in the following order Big - little - big, making sure the half circles all line up. Fasten with 2 of the #6 nuts and bolts.
The larger pulley is a little more complicated. First: fasten the layer with the smallest holes to your servo's horn, and fasten the horn to the servo. Then laminate the other two layers and fasten them all together with the remaining set of #6 nuts and bolts. Use the #4 nuts and bolts and the two remaining acrylic pieces to fasten the servo into the open slot in the junction box. Replace the nob on the dimmer switch with the smaller pulley. Run some sort of belt between the two pulleys. I found a regular rubber band to work just fine (though, I'm not crazy about how the rubber band looks with the rest of it)
For the code to run it on, check out the Arduino playground's servo tutorials. The HS-322HD has a full 180 range and the 2:1 ratio of the pulleys enables that to fully rotate the dimmer switch.
See it in action here -> andrewparnell.com/?/blog&id=148
