Geared Arduino controlled Dimmer Switch

thingiverse

Revamping an earlier design, I replaced rubber bands with a set of gears for my pulley system found at thingiverse.com/thing:566. The new gear setup eliminated slipping and improved accuracy. However, be aware that gears cause the dimmer to turn in the opposite direction of the servo; adjust your code accordingly. For this project, you'll need acrylic sheets (7" x 11", 4" x 8"), assorted machine screws and nuts, a NEMA compliant rotary dimmer switch, outlet, power cord, 3-gang junction box, an HS-322HD servo or small wheel horn, Arduino, and a wall wart. Inside the junction box, wire the outlet and dimmer switch to your electric plug. Cut the acrylic sheets to size: face plates from 1/16" sheet, pulley bits from 1/8". Mount the servo onto the top faceplate layer, then attach both layers to the junction box using large-holed bolts for clearance. Assemble the small gear with two 3/8" nuts and bolts, and affix it to the dimmer switch. Attach the large gear to the servo and adjust its position. Remove the large gear, fasten the servo, reattach the large gear, and secure the horn. Adjust both the dimmer and servo to 50% (90 degrees on the servo, a half rotation on the dimmer) for optimal performance. Follow Arduino playground's servo tutorials for code guidance, as the HS-322HD servo has an 180 range and the 2:1 gear ratio fully rotates the dimmer switch.