Fan/Motor System - Part 1 [Rod and Fans]

After a year and a half, I finally got around to fully completing the vibraphone... almost. I've started building the fan and motor system, which is what produces that vibrato effect you sometimes hear. When I originally built the vibraphone I decided to not include that feature just because it's really complicated and would add much more time on top of the already lengthy 10 month process. I've had some free time lately so I figured I'd get my hands dirty with this.

When I originally built the resonators I created notches on the tops of them so that I could one day come back and add the rod and fans like I'm doing now. The vibrato effect works by essentially opening and closing the resonators. There is a long metal rod that runs along the center line of the tops of the resonators. At each resonator tube there are metal discs attached to the rod. The entire rod spins via a motor pulling a belt. This creates a constant opening and closing of the tops of the resonators.

I started this portion with the rods. I found a metal supply website that had the exact type and dimension I wanted: 1/4" diameter hollow stainless steel rod. This type is going to be much smoother and straighter than rods you can buy at Lowes or Home Depot. The rod rests inside holes drilled through these plastic rods attach perpendicularly to the resonator frame. These lift the bar up so it doesn't actually touch the resonators anywhere. And fewer points of contact means less friction.

The next step is to make the discs or fans. I used the thinnest aluminum sheet metal I could find at Lowes. I cut them them out into a sort of elongated circle shape a little smaller than the inner diameter of the resonators. 

I didn't cut them into perfect circles because I formed their shape by bending them around the rod so there's a hump in the middle. So after that shape is formed the overall shape looking down on the disc is a perfect circle. 

Then I painted them black... of course. At the high ends of these rods I attached sliding door wheels that will allow the belt to turn the rod.

I used a 2 part 6 minute epoxy to glue the discs and wheels to the rods. The discs were glued alternating direction every resonator to make the whole rod balanced and not weighted more to one direction.

The next thing I need to do is buy a motor and build a housing that it will sit in and attach another wheel to it that will pull the belt. I'm also going to be experimenting with controlling the motor with an Arduino probably. This will allow me to control the fans in ways that you can't do on any other vibraphone, at least that I know of. I made a video to test how the effect of the fans sounds. I simply pulled on a string attached to one of the wheels on the rod under the natural keys. Stay tuned for the next post on the motor. No clue how long that will take though.