Thursday, September 4, 2008
ok, so i probably should have put up a few more posts during the development of this project. i did take a bunch of pictures along the way so i guess i'll just have to narrate them as they upload.........
this is the keyboard. its about the size of a stick of gum. this and the amplifier board are all i am using of the the entire keyboard. the rest will probably get used for a future project.
here are some pictures of the paint job. i used red because every where i go all the stores are out of orange fusion. this red was pretty old and took a long time to dry. it also picked up a few scuffs when i was putting the hardware in(nothing too noticeable).
fitting the hardware was pretty challenging. the keyboards went in pretty easy but the knobs had to be carefully sanded and trimmed to fit without rubbing the surface. i dont like knobs that scrape.
here is a picture of all the hardware in place. the keypad is still loose.
here is the underside.
this is the oscillator that caused me a lot of grief(notice the direction of the 4148 to the npn)
after meticulously planning and documenting my work(taking my time), i got to a point where i felt that i could finish this project in about an hour. on monday i figured i'd use my day off to finish this piece and get on with my life. well i was right, it only took an hour to wire it all up and put it all back together, but when i turned it on the damn thing started glitching out like crazy. it sounded kind of like the output from the chip might be shorting to one of the function pins. this really really made me mad because i had already pretty much covered everything inside the keyboard with hot glue in such a way that it would never come off again. the worst part was that i didnt know which board to unglue and fix. after a couple of hours ripping up glue, i found out the short was in the keypad which just happened to have the most glue. i fixed the problem and reglued the whole thing confident that i had fixed the problem and that i wouldnt ever need to get back in there. but, the problem persisted and i had to rip it all out again. the problem was that i had to solder to the tiny tracings on the circuitboard because there were no pads to solder to. this made for some tricky soldering. after finding the short again, i made sure that the wires were on there tight and i kept the keyboard running while i glued it back in. by the time i had finished all this, 5 hours had gone by and i was pretty stressed out. in fact i was so stressed out that it didnt seem to bother me so much that the neck of the guitar had been resting on the tip of my soldering iron and melted a big ass hole in it. i just let out a quite "oh fuck" and put it back together. once it was back together i noticed that the paint job wasnt planning on sticking for too long. i imagine that this keyboard will be noticeably scratched all in due time. damn. but at least it was working. i took it up stairs and started playing with it but noticed that every time i turned the lfo on and off it would reset the keyboard and i would lose all my saved stuff. also the second lfo didnt work at all. damn damn. i decided to just let it go and fix it all later.
i went back in to the guitar and found the problem with the oscillators. i had to rebuild the circuit on a breadboard but that didnt take long. i fixed the reset problem. it was the lfo on/off switch, it was grounded. easy easy. once i put it all back together, i put a sander bit on my dremmel and cleaned up that melted spot on the neck. fortunately it can pass as a thumb pad.
now it all works how it should and im happy. i didnt get to try the level meters but oh well.
here is a truth table for the keypad
thats it. (not for sale)