My summer in San Luis is wrapping up, and the parts and tools needed to complete the next batch of Magnetic Cellos are either in the lab, the mail, or a nearby store. Lawrence and I have finished using the laser cutter on campus, and all that is left for me to do is… quite alot, actually. But before I explain what still needs to be done, here are some pictures of our progress:
Here is the newest coil. We tried to use acrylic glue to join the 4 acrylic layers of the coil housing, but because acrylic glue is toxic and hard to work with, we decided to use 6 screws to hold the housing together. These screws will be under the neck and out of view.
After finalizing and testing the design of the coil, Lawrence went out and cut out enough housings for three version 7.0 Magnetic Cellos:
And after a last minute decision to add 50% more magnets to the magnetic bow, we cut out and the final template for the neck and body of the instrument and three of each layers of the bow housing:
On the electronic front, my printed circuit boards came in the mail:
And I immediately populated the circuit board:
When I first used this circuit, I was getting terrible noise and tone problems. But after a few hours of frustrating troubleshooting, I found that I only needed to ground a few components mounted off the board, on the control panel. The circuit now works great, is easy to solder, and looks professional.
So we’ve got the electronics, the bow, and the coil ready for action, and a template to cut out the neck and body of the instrument. I’m going to be going home in a few days, to, among other things, eat some home-cooked meals and learn to drive. But I will also be sourcing some wood and some music stands to be turned into endpins, using a jigsaw and router to cut out the wood using the laser-cut template, assembling and winding three coil, wiring and gluing three magnetic bows, drilling out holes in three aluminum boxes to mount knobs and switches and other sundry panel mounted electronics, soldering together these panel mounted electronics, staining the body and neck and coil, soldering together two circuit boards, applying the ribbon sensors to the neck of the instrument, screwing together the neck to the body, the coil to the box, and the box to the body, and, of course, burning or engraving version and serial number, the date, and my signature in a discrete part of the instrument.
That was the longest sentence I’ve written in a few years (made longer by my unfortunate choice to use the gerund ‘-ing’ form of the verbs) and I won’t quiz you on what I just wrote. But the effect is there: I am going to be very busy in the next three weeks before school starts again. I’ve built half a dozen Magnetic Cellos before, though, and this latest version is designed to be relatively easy to build.
I’ll keep you posted on my progress. Don’t forget to follow me on twitter at @Magnetovore if you want updates (with pictures) of my progress.