October 2, 2010 Comments Off

Hi-Hat Machine Taking Shape

Yeah, I know. These are my baby photos. I promise no Honor Roll stickers will ever appear on the robots.

The frame of the hi-hat machine, which, although it’s difficult to see, really ties the room together, is made from mahogany and held together at the miter joints by dovetail splines of African Padauk. Padauk is one of my favorite woods. I had a few pieces left over from a love seat I built a couple summers ago, and I figured dove tail splines made a better use than chop sticks or fountain pens. I routed out large holes in the frame to allow sound to escape; reverberation in the wood enclosure can color the sound to creat a flat, bathroom stall kind of ring, which I think I’ve mitigated. The red piece of wood on top of the frame is also Padauk, which I cut at strange angles to add some modern flavor.

Unlike a regular hi-hat, the top cymbal in my machine is closed by default. Gravity alone is insufficient to squeeze the cymbals together for a clean “chk” sound, so I use a spring, which you can see in this bottom photo, to pull the top cymbal down. Lifting the top cymbal is accomplished by running a roller chain from the hi-hat’s vertical rod around a sprocket above the frame and then back back down below the frame to a driver sprocket. That driver sprocket is turned by a beast of stepper motor from Anaheim Automation. This motor is slightly bigger than a soda can, weighs about five pounds, and can generate a ridiculous amount of torque. By the way, Anaheim, why haven’t you gotten back to me about the endorsement deal? I’ve already got the racing jacket; don’t let that prime pectoral real estate go to Black & Decker!

Obviously, the machine is missing electronics and solenoids to hit the hi-hat. That’s next, and it’s the easier part of the project; figuring out how to lift the top cymbal was the tricky part, and that’s done. I’m aiming to get the machine to a functional state before I leave for PopTech in mid October; once it’s functional I need to tweak my code to handle the additional performance instructions, and once that’s done, I just need to figure out what I’m going to do with it.

Filed under: Machinery

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