*Objective (and explanation...)
In this lab I attempted to create an instrument that used the motor to turn a pick that strums a string.
This lab was initially a no-go because I could not create an instrument body that was suitable.
After Thursday's lab on servo-motors I attempted to retry the project using a servo motor to "tune" the string. This time the hardware proved to be no problem, but I had trouble with wiring multiple elements, and could not function the servo and motor at the same time. One conclusion that may be drawn is that to attempt to work out the kinks in a system by further complicating it is perhaps not the wisest course of action...
However, let's focus on the positive...
*Materials and procedure (please refer to the images)
The instrument body is fairly simple - made out of wood with a bridge to secure one end of the string, a hole to allow the strumming action, and no neck as all pitch modulation will occur via the servo.
The strumming mechanism is the motor, which is secured to the instrument body with insulation to reduce the whine. The hole in the body allows the "pick" to spin. The pick is a simple piece of electrical tape.
The tuning mechanism consists of a wooden peg around which the string is wound. This is anchored to the arms of the servo.
The controls include the serial port of the arduino program which is used to determine the pitch (this could easily be controlled by a pot) and the pot, which is used to control the speed of the strum.
*Code
Not to bore you, let me offer a short review. I copied the code to control the motor and the pot pretty much without alteration, the only important exception being that I reduced the range of motion of the servo in order to avoid tearing the mechanism apart and because the string required little change in tension to change the pitch of the note.
*Conclusion
I did not achieve my goal in this lab, but I think with some help with the circuitry I could get this running.
Comments
Comments from TAs
Cool idea -- I like the combination of the motor and the servo to both actuate and tune the string! I'm sorry it didn't end up working... If you have a chance, definitely bring it by office hours and we can try to help you out. Since we're going to be designing musical instruments in a couple of weeks, your experience might provide useful inspiration. (And if you can get the instrument working, it would be great if you'd bring it into class to show everyone else.) The mechanism looks really nice!