It’s week two of the HotHouse program, and the first week we really had to dive into our work.
After getting some pointers from fellow students at the HotHouse, I was able to design the current prototype of the Magnetic Cello in Solidworks:
And then experimented with moving the box lower, underneath the coil. This would both look better and mean a stronger mechanical connection between the neck and body of the instrument:
It may just be because of my recent consumption of space video games, but the latter picture looks like a spaceship, and an ugly one at that. But the good news is that we are in the process of getting more help with the design of the Magnetic Cello. We have been getting in touch with student architects and mechanical engineers, and a professional woodworker or two. These folks will help design the Magnetic Cello to be more durable, easy to manufacture, and (probably most important to you) ergonomic and pleasing to the eye.
These same people will also be able to get us the skill and tools needed to build a professional instrument. Access to CNC machines, laser cutters, and a skilled woodworker are now almost within reach. And we are working on ordering custom enclosures/control panels (Hammond looks promising). This all adds up to better quality and easier scalability (if the Magnetic Cello happens to catch on).
Also, this weekend the Digikey shipment came in, and I was able to improve the circuit a bit. I am no power systems expert, and it turns out that I do not have to be, because a part I ordered is able to precisely hold a +/- 5 volt supply. In a single component. With any input between 9 and 36 volts. Finds like this always make me glad to design in an age where many needed circuits are already integrated in little black boxes that can be readily found online once you know what you’re looking for.
I also replaced the mechanical relays, the ones that are used to switch strings, with solid state optoisolators. Optoisolators, which control to flow of current by shining light on photodetectors inside a small chip, are lower power, smaller, and infinitely quieter than a magnetic coil pushing a strip of metal back and forth. You may have heard a clicking sound in the last Magnetic Cello video. But that sound is gone for good:
My electrical engineering buddy will look over the circuit in a few days and point out if I’ve made any obvious oversights.
Until then, I’ll be fixing up a few noise problems and working on a new body design, with help.
Now to email back a few future customers. Remember, you can always contract us at email@example.com.
What do you all think about changing the design of the body of the instrument?