Update #3: Controlling Multiple Electro-Magnets

  This is an overview of our new design circuit and the issues that we have encountered using it. Our prototype board consists of a micro-controller on a breadboard, 6 resistors (10 Ohm's) and 6 transistors. However,there are multiple issues with this current design. The biggest issue right away is that the strings themselves are not resonating at the same volume as they were if there was just one. One main reason is that this is occuring is because we programed the circuit to release pulses for the strings. So, instead of resonating constantly, they are going down from the low E to the high E string resonating for about one second each. The sound is very faint  because we do not have the power to accomodate all the six magnets. The height of the magnets also affects the resonance of the strings. We are running on a 19 amp power supply for the moment and working with such a small circuit with the amount of resistance we have is difficult. Not only this, but our circuit must be able to both power and control the stepper motor and the magnets at the same time.

   With these revelations, an integrated circuit is our best bet to fix some of these issues. Using six microcontrollers for the strings and one extra to control the ticks of the stepper motor are the main portions of the circuit. The circuit will need two separate power sources which will require being plugged into a wall and a power supply.

    Figure #1: Integrated Circuit Design (Final Product)

   There are multiple issues with the circuit at the moment and the way to get around these issues is to test many portions of the circuit using an oscilliscope or multimeter. Another big problem is that many of the microcontrollers, transistors, and capacitors need to be constantly be soldered for repair. This essentially makes the programming of the microcontrollers difficult which can cause damage to the board and the the embedded chips.

Update #2: Basic Build for Linear Track

   To make the instrument that is being designed play chords, a linear belt track run by a stepper motor is being incorporated along with a slide. The linear track system will resemble one that could be found in a 3D printer. Since the instrument being used is a steel string guitar, there are multiple issues that needed to be taken care of which is why a simple model is being built. The main issues that are being faced with this linear track idea have to do with the ability to have enough pressure to push down the strings and have smooth enough movement to allow for proper play of the song. When playing chords, the guitar will need to be tuned to an open chord which means a simple baring of a single fret is needed to play a standard major chord. There is a minimal amount of flexibility for which notes can be played with our current method however, this is a less complex system than using say solenoids to push down individual strings.

   Now, for the general track design. The structure created needs to allow for enough room so that the belt and slide system can cross enough frets (depending on what chords or song is being played) and be sturdy enough to resist any motion provided by the stepper motor and belt/pulley system. Each structure will need enough clearance over the guitar fretboard and neck to not interfere with the strings as well as be at just the right distance to keep the belt taut. Greasing up a pulley and the belt will decrease frictionallowing for moderate changes in performance.This belt/pulley system itelf is only covering the horizontal motion across fretboard.

   So how are any issues with pressure and clear sound of the strings going to be resolved? Well for one, the slide being utilized is going to be brass. For the strings being used this will provide the perfect tones but the slide itself is heavy, which needs to be addressed in the design. Along with this, a set of thin, steel bars are being placed across the structure to guide the slide as well as provide just a slight amount of pressure that needs to be applied.

    Figure #1: A simple plastic model of our metallic track design



   Now, one issue that came into question was the fact that when the guitar is laid down, it does not lie flat, To resolve this issue, a neck cradle of sorts was cut from styrofoam and placed just under the neck.This, in turn, keeps the belt system running on a flat surface. The structure that needs to be created will be made out of wood and will be one continuous structure. The first prototype was two separate pieces which allows for the length of the belt to be changed until we find the correct orientation that works.

    Figure #2: Prototype w/o metallic bars

    Figure #3: Prototype track w/ guitar

Testing will need to be done to minimize mechanicl error with the stepper motor as well as the belt. This can only be accomplished once an updated version of our circuit is created.

Update #1: Getting Started with a Prototype

  
  One of the most important parts if not the most important part of the our magnetic resonance guitar is the magnets themselves! So, a simplistic prototype of our model was created with some parts laying around. By wrapping wire around six different steel rods and surrounding them with metal which acts as a sort of heat sync, we have created our first electromagnet that mimics what a magnetic pickup would look like on a guitar.

  Just to start, we are working with one electro-magnet. Since each guitar string resonaces at a different frequency, each of the electro-magnets need a specific amount of voltage. This is somewhat tricky to accomplish without the use of a micro-controller. Our plan is to use a micro-controller along with 6 transistors to regulate the amount of voltage for each magnet thus regulating the frequency for each string. Below is a sample of what we can accomplish sound wise with our design. However, it becomes trickier to deal with multiple magnets. For now, we will stick with one magnet and work on building a general circuit on a prototype board.

                         
Resonating Low E- String: (82.8 Hz)





  As you can see, it is possible to create a loud, distinct sound just with a magnet. Power will definitely be an issue when it comes to supplying the magnets. One of the guitars we will be using will have a built in tuner so it may have to be taken out to place in our circuit or to allow wires from a power supply for said circuit. This will be easier to deal with than creating a mount for the circuit on the outside of the guitar.