Today I finished the build section of the project! I began by cutting a part of the same plastic box used for the front kaoss pad mount to fill the gap in the kaoss pad body where the touch screen was. I then attached the serial connector to it. This is not ideal as a permanent solution as it renders the LEDs inside the unit useless and so I may replace this with clear perspex or something similar at a later date.
I then used more of the same plastic to make a scratch-plate to replace the yellow one provided with the guitar and cover for the back of the guitar. It's not the most elegant solution but will do for now!
Finally I glued the nut to the headstock of the guitar and screwed on the truss rod cover.
I was then able to put strings on the guitar and plug it in to an amp!
Completed guitar & kaoss pad
The guitar circuit works, though the tone pots do not work properly so this will need re-soldering, however for the time being the guitar and kaoss pad are both functioning.
So, the only remaining problems to deal with are:
Setting the intonation of the guitar
Fixing the tone pots so that they work correctly
Finding the source of a slight hum that is only really present when the kaoss pad is turned on (possibly an issue with the lack of shielding between the guitar and touch pad wiring inside the guitar)
Then the purely aesthetic changes I would like to make include:
Replacing the black plastic with something more durable, particularly the replacement screen on the kaoss pad body.
Replacing the yellow hardware
Add the originally planned LED circuit behind the touch pad
I plan to upload a demonstration video of the completed guitar once the intonation is properly set up to make the guitar playable.
Today I have begun my final push to finish the build portion of the project and, after a very long day, am nearing completion.
I began by spraying a few extra coats of paint on to the body. While waiting for these to dry I soldered the wires on to the four touch pad connections to allow these to be connected to the serial connector in the guitar.
Touch pad connections soldered to wires ready to be put in to the guitar
I also cut a front mount to hold the touch pad in place on the guitar body. This was cut from a plastic box but may be replaced at a later date if a stronger and/or more attractive material is found.
The front mount cut for the touch pad
Once the paint was dry, a chisel was used to carefully level off the top ridge of the support for the touch pad and two additional pieces of wood were screwed in to either side of the kaoss pad cavity to brace the touch pad against the front mount.
Touch pad cavity with supports on three sides and a small section filed out at the bottom to allow space for the ribbon cable to fold own in to the hole.
Some parts of the outside edge of the guitar body would not allow the paint to stick and so have been left for now so that the electronic side of the project can be completed. I will most likely come back to these after the project is finished.
Part of the body where the paint would not stick.
Next the various parts of the guitar electronics were added to the body. The bridge and tailpiece bushings were hammered in to place as the holes drilled were a very tight fit. Then the pickups, selector switch and volume and tone potentiometers were put in to place with wires fed through to the various cavities.
Pick-ups and 3-way selector in position with wires fed through the cavities to be connected
The Pickups were then soldered to the pots. The main problem at this stage was that the wiring provided had already had some of the soldering completed but what had already been done did not match any wiring diagrams that I could find, however I managed to combine information from several to complete the circuit.
Volume & Tone Pots in position and wired up
Then the three-way selector was wired up. This was difficult due to the fairly low quality of the wires that came with the guitar body.
3-Way Selector Switch connected up
While the volume and tone pots were being connected up, the hold button was also put in to place and the wires connected to it fed through the additional hole drilled for the kaoss pad wiring.
Hold Button in position between the volume & tone pots
The pickups and pots were then all connected up the the input jack which was screwed in to place.
Input Jack Connections: 1 = Hot, 2 = Ground, 3 = Input Jack Tip
The two wires for the hold switch were then connected to the serial port. Once all of this was complete the touch pad was put in to the guitar and wired through to this same serial port.
Hold Button connected to serial connector
To ensure that the various kaoss pad connections matched to their original locations, the serial port on the guitar was wired identically to the one on the kaoss pad using the arrangement shown here:
1-4 = Four Touch Pad Connections, 5-6 = Hold Button, X = Unused
Finally, the tuning pegs were attached to the headstock of the guitar and the kaoss pad connection was tested.
Tuning Pegs attached to head
The remaining steps should be completed tomorrow. These are as follows:
Cover the back of the kaoss pad cavity
Glue nut to the headstock
Add scratch plate to the guitar
Put strings on the guitar and test the pickups/pots/selector switch
Attach strap buttons
Cover the hole in the kaoss pad & attach the serial connector to the cover.
Having drilled all of the necessary holes for the hold button (positioned between the four volume and tone pots to make use of the pre-existing control cavity) and for the additional output port, I have been able to begin painting the guitar body.
I have also test-fitted the neck to the body and drilled pilot holes to allow me to attach it after the painting is complete.
Today I have been making all necessary changes to the guitar body. I initially drilled holes in the corners of the marked space for the cavity and used a hack saw to cut along the edges.
However it quickly became clear that I did not have a saw that would reach far enough in to the body to use this technique all the way around the shape and this approach was very slow. Instead I carefully chiselled the shape out by shaving off layer by layer. This was much more effective, though did not give a very tidy finish on the fourth side, which will need to be smoothed off before putting any electronics in to the hole.
I also drilled holes down for the bridge and tail piece bushings, though I need to find a very slightly wider drill bit to widen these holes enough to fit.
Before the guitar could be painted and assembled, the holes for the tail-piece and bridge bushings needed to be drilled and additional a cavity for the touch screen cut out of the body. In order to accurately measure the touch pad cavity, it must first be removed from the main body of the unit.
The four connections between the PCB and touch screen from the KP-1 Service
Manual
I began by removing the back of the kaoss pad, followed by the two large PCB's, the third small board containing the headphone volume control, and finally the touch screen itself.These four connections are wired via a ribbon cable which must be disconnected from the PCB.
The connection can be seen at the top of the unit in this picture.
All PCB's and touch screen removed from the unit casing
The ribbon cable was connected to the PCB through a small plastic jacket which I opened to disconnect the touch panel. I then had to de-solder the four connections of the remaining half of the jacket from the the PCB
The removed panel and half of the plastic jacket
Remaining half of the plastic jacket
De-soldered connections on the PCB
The jacket was then put back together to give something to solder connections to later in the build.
Having removed the touch panel, I was able to position and draw around it on the guitar body and work out the best positions for the bridge and tail piece.
