I am writing this late at night because if I don’t write this now, I’ll never get around to it.
I just finished a new coil design for the magnetic bridge of the magnetic cello. It works quite well, giving the cellist just enough space to slur notes. It also looks nice to have the copper wire between two sheets of clear plastic.
The reason that this coil works better is because it goes out, not up. In past coil trials, I would wrap as much wire around a single point or bar as I could, to maximize induction. But this lead to problems with the response of the bow–the space about the coil that actually made good sound was centered around that point. This trial is much flatter, and the wire is more spread out. The magnetic field from the bow ‘cuts’ into the wire more gradually and allows for better control.
This coil shape did not spring from my own mind. I was stuck on increasing magnetic induction and voltage, when I really need was to work on linearity of the bow. What lead me to try design was asking for help from upperclassmen in the IEEE lounge and from a electromagnetism professor. Being a lone inventor is cool. But actually getting an idea to work properly, and possibly to market, is too much for a single person. We each a limited domain of skills and knowledge, and often it makes the most sense to ask for help from others. “It’s not what you know, but who you know.” Obviously rings true in the world of business. But in many ways, it is also true for engineering.
With a good coil (which can be improved further by even more flattening), the magnetic cello is well on its way to becoming a ‘real’, playable instrument. Electronic noise and figuring out the best way to put all the parts together are still challenges, but bad coil response was the last ‘huge’ problem I can see in development.
I’m quite busy with class, but I’ll make another video when I find time.