Assembly Day 2

Just continuing where we left off before.

The Assembly

Here are the videos of my day spent assembling a portion of the GuitArduino. Sorry for the abrupt endings, needed to get some sleep.

Build Day 1 - Overview

I haven't posted anything in a while but today was a big day. I have been working and filming this project since 11 a.m. today, but I don't think I will have video of this for a while. The video shows the entire process of me building up to this part of the GuitArduino (separating the neck from fret board, removing frets, drilling holes, putting in LEDs, all that fun stuff). The video below is just a preview of what I have completed. 

How to make a simple electric guitar

I found this really cool instructable on making a cheap and dirty electric guitar. Since we are going to be making our own guitar pickups, I find it pretty neat and definitely want to build one in the future. Check it out.

http://www.instructables.com/id/How-to-make-a-simple-electric-guitar/

The Guitorgan

Found a site with some good pictures of a guitorgan and it's inner circuitry. (Look at the picture of how the frets are sectioned into 6 pieces.)
http://www.thegearpage.net/board/showthread.php?t=445142

Since a resistor network will never work  I think separating the neck the neck has started to become more of an option. Over the next two weeks I would like to clean up the guitar in its current state before tackling that project.

In the meantime my senior design partner is going to be experimenting with making his own guitar pick ups and try to recreate something like a roland gk-3. I look forward to future posts on that topic.

Proto Demo

CLICK THE WATCH ON YOUTUBE BUTTON IF YOU GET "VIDEO IS UNAVAILABLE"

Trying to hook you in with keyboard cat! So far this is what I have done, but I still have a long way to go. The code is still sloppy so their is still some improving. It still does not have to capability to hold down notes that are frets next to each other. I can hold down power chords or just singular notes, as I do in the video. I posted the current code in the comments section if anyone is interested.

Coding...

Hey just to keep updated, I am currently working on the code for the guitar. It is not very long code just polishing it up and working out a bug or two. Hopefully I have the code and a video up by today or tomorrow night.

MIDI Break Out Board

Just received the MIDI Breakout Board via Sparkfun. Soldered it up and uploaded some sample code via Arduino Tutorial and it works great. The Arduino is controlling to sound output by the synth. Now I have just been messing with the code and various MIDI output in order to output chords and such. Together the m-Audio Uno , and MIDI-OX (freeware), have been great for debugging the output of the MIDI Breakout Board or the synth. I think the next step is to work on the monophonic MIDI guitar...

Rev 1 - Behind the Scenes and Why It Doesn't Work

 The "schematic" above depicts the initial strategy of how the guitar is currently setup for testing. When a string is pressed, shorting the string and frets, it creates a voltage divider, allowing us to take in the information via Arduino.

[****DENOMINATOR = Rin + R1||R2]

I went through one-by-one and tested each string and fret and was getting appropriate analog readings with the Arduino, but that didn't last long. It wasn't until I tried to test for holding down multiple frets that I noticed the flaw in the design.

[****DENOMINATOR = Rin + R1||R2||R3]

Notice how the two strings being held down (X). When the E string is being pressed against the fret, the fret becomes conductive, allowing the B string to become conducting and allowing R3 to become apart of the circuit. This is not what I wanted.

I thought I had a fix for this but at the moment it does not seem so. I do have a potential fix but it would involve ripping apart the neck of the guitar and I would like to spend a few days with a setup similar and less evasive before I try and do so. 

What we have now is the ability to read a chord that does not have a note on a fret immediately next to it (power chord), or to read a single note. Today I am suppose to receive the MIDI break out board and will try to program the GuitArduino to take one input at a time. It is not what I want the final outcome to be but it will be good practice in the programming side and the final strategies may be the same. I will post video if I get it running accordingly. The first MOOG synthesizers were polyphonic...

Testing

Well it seems I have hit a speed bump today using this method. It is OK however because I have developed another method using resistors that I will go into more detail about soon. Let me just post some pictures of what I have been up to.

I will post a more in depth explanation as to this setup soon. While testing out the strings with the Arduino, I discovered that  I was unable to hold down more than one note at once. If I held down a chord my resistance readings would go haywire. I do not want to design a monophonic instrument.

The Beginning

The time has finally come to begin designing the interface. This last implementation is a stretch from the original thought of design which entailed separating the neck of the guitar (Not fun and A LOT of wiring). The goal is to find out where your finger is on the frets and strings. The strategy for finding out where you finger is is a simple voltage division. According to where you finger is placed on the string, you will get a different resistance reading via different resistors tied with to the guitars frets. So the guitar string is like a long wire in and input resistance and the frets all have a different resistance value coming off of them. For you EE's it is simply two resistances in parallel. Anyways this resistance measure will talk to the Arduino via analog input and from there we can determine which string is being pressed. Pretty much this sample project, just interfaced differently

I began prepping the guitar by tinning the frets. Be careful if you do this, your top could by laminate and burn your guitar. Anyways don't hold down the soldering iron for too long.

Then came soldering on the resistors the neck.

The here is is all finalized. Next step coding and checking....

What is GuitArduino?

GuitArduino is going to be an open source project for turning your guitar into a MIDI machine like a synth. Now there are devices that already do so such as a Roland GK3, but these devices are a bit expensive. The goal is develop a MIDI output guitar that can be done in under $30. What can you do with a MIDI guitar? Just go to YouTube and check out some videos.

Hopefully I don't hit to many speed bumps on the way and if any one has some suggestions, advice or question, feel free to contact me. Thanks.