Wednesday, December 31, 2008


i threw this one together today. i've been in the basement since 11am. thats pretty good time if you ask me. basically its one of those cheap digital cameras that you find at walgreens for $10. i found this one at goodwill yesterday. i havent been able to connect any wires to the chips on these things because i dont have the right equipment yet. although these are extremely bendable, for this one i just removed the ir filter and added a better lens. oh yeah, i also rehoused it into a badass little kids toy camera. i added the lens(big pain in the ass), switches, usb io, viewfinder, and a battery compartment.

Saturday, December 27, 2008


i have been working on these in secret for the last month. they are pretty basic. they consist of a generic drum machine circuit and an 8-note keyboard. some have joysticks, some have just a pitch bend for the drums. the 8-note keyboard will not make sound unless the drum circuit is making sound. the notes are cross modulated with the drum sounds making for some interesting tone variations. each has a 1/8" output jack and power indicator LED. these are capable of many different functions despite the limited interface. the black keys act as the drum circuit's function switches.
these keyboards were intended for gifts to my family and friends for the holidays, although there will probably be more to come in the future.
chick on this picture for bigger view.

Wednesday, November 12, 2008


this is a little something i've been working on for the last week.

the rain in portland is out of control. i decided not to even bother with a paint job. instead i just used a kind of matching lego color scheme. in all, this only took about two and a half days to make. i probably could have finished it in one, but i didnt realize that until half way through the first day. the second day i was distracted by stuff thats not interesting. i finished it today in about 3 or 4 hours.

the circuit came from a toy keyboard/guitar convertible. you know, the one that looks like a guitar
 and then folds out in to a piano.

it had a few other functions on it but they sounded crappy to me. the toy its housed in is this little baby piano music box thing. i dont have a lot of pictures. this thing went pretty fast. but who cares what it used to look like anyway? here is a functional diagram


here is the video that i thought was good until i uploaded it

Monday, October 27, 2008


well, its been a long time since i've posted anything on here, but i have been busy. actually this might have been the longest project so far. hmm, where to start... soon after i finished my last project in early september, i started looking around my collection of toys and keyboards trying to come up with a new direction. after about a week of dabbling with different toy circuits, i found a keyboard in a junk box full of toys i had planned on getting rid of.

its a pretty common keyboard. it has 8 different drum beats, some really terrible timbres, 4-5 voice polyphony. the thing that really got me interested in this keyboard is that the lm386 amplifier had an additional circuit built on to it to flash two channels of leds to the sound of the keyboard. thinking at the time that this would be a quick project to throw together, the fact that that circuit was already built was a selling point. once i found the circuit i wanted to use, it was just a matter of finding something to put it in. i found this old "creatoy" keyboard that i had picked up at a thrift store a long time ago.

this isnt the the one i used. i forgot to take a picture of it before i tore it all up. its pretty much the same except the one i used had like a little piano or something on it. after searching for keys to put into it for like two hours, i found a two octave keyboard that fit alost perfectly. after some sanding, they fit like a glove. i then cut out the faceplate from a spare piece of plastic.

then i had to figure out how to consolidate the circuits to fit into the new enclosure. after carefully deconstructing and documenting the circuit, i put it all back together in its new form.

for the function switches i used a keypad from a portable clock i found at goodwill. i carefully buffed the silkscreen off of the rubber pads with a sander bit on my dremel. unfortunately the keypad that originally went with the keyboard keys was rotten and unusable, so i used large push switches from an old typing keyboard. i was considering mini tactile switches, but you dont get to push the keys very far with those. i wanted something at least a little bit more natural. that is why i used bigger keys for this in the first place. the battery compartment gave me a lot of grief. the original compartment was a space hog and only produced 4.5 volts. i cut a hole that was big enough to fit a 4 pack of aaa's, but they had nothing to rest against. i decided to cut out a bigger hole and just throw in a 6 aa battery holder with a battery door and everything. at this point i didnt know what additional circuitry would be going in the keyboard and how much voltage i would need. if i need 9v, no problem. if i only need 6, no problem.

at this point it was getting pretty late in to september. heidi and i went to LA for a week and came back in october. when i got back i had to familiarize myself with what i had done so far on this project. i decided to use the led circuit to modulate the pitch of the keyboard with one channel, and the cutoff of a filter to give it a cool auto wah sound. i knew that adding a vcf to a shitty toy was going to be a big pain in the ass, but i was up for it.

i soon found that i couldnt simply insert the filter in between the chip and the amplifier. there wasnt enough signal? i decided to add the filter after the first 386 amplifier and the add another one after the filter. im sure there was a more sophisticated approach to this but i think i tried everything. i breadboarded it up and cleaned up the ins and outs to get as clean a signal as possible. i worked great. i was having a lot of fun playing with it on the breadboard. once i put it all together on a circuit board things changed. i kept getting this retarded buzzing sound from the chip. after days and days of trying to eliminate it, i realized that the filter was just not going to cooperate with this chip. i tried switching the 386 amps for each other, rebuilding the filter with a different chip, and hundreds of combinations of passive filters between the ins and outs of everything. in the end i found that adding a gain capacitor to the final filter helped a bit but you can still kind of hear it. i decided to get rid of the pointless volume pot and replace it with a gain pot. when its closed the filter makes the 386 oscillate. kind of a pseudo resonance knob.

oh yeah, i also decided to add lfo's. go figure. the switches that turn on the env. modulation have a third position that turns on an oscillator that modulates the respective effect(pitch and/or filter). the oscillator speed is modulated by the envelope coming from the keyboard. this doesnt make sense does it? you'll see in the video. there are also switches that change lfo shape between triangle and square. the max frequency of the two oscillators is controlled by a joystick. the two psp joysticks control the minimum and maximum depths of the pitch bend and cutoff. there is also a pot right below the pseudo-res. knob. it is the fine pitch tuning knob. there is a switch to the right of the lfo joystick. this switches the lower octave to the octave above the high octave. the switch above that is a reset disable switch. this particular keyboard resets itself after 12-13 measures. super annoying. i used the audio signal to throw a transistor that switches the one key function(makes no sound). this function only worked with the rec.-play and the demo functions. i hadnt planned on keeping any of those, but i soon realized that if you use the one key function on demo mode, you can get these sweet loops to mess with. this wont work if the transistor is connected, so i added a disable switch. the blue square button to the right is the demo switch.
ok, what else? oh ya, there was a mic with this keyboard at one time so i added a line in. it also modulates the vcf and pitch bend and stuff. i've been having some fun with my guitar through it. it also has a line out that disables the speaker.

as far as the paint job is concerned; WHATEVER! it started out perfect and then i dropped it on the floor. now its scuffed. also, i put this kind of like Styrofoam protector around the lfo joystick to protect it while i was working on the inside and i hot glued something inside that heated up the other side of the faceplate that was touching the foam. it melted and bonded with the paint. oh well. live and learn.

well, thats about it. or at least thats all i can remember sorry if this is all jumbled together like crap. its hard to fit 2 months in. let me know what you think. i will post a video soon. by the way, dont be afraid to click the pictures to see it in high res.

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)

Thursday, August 21, 2008



last Thursday i started this project. the idea came to me as soon as i found this toy guitar at the bins. i wanted to have a guitar with a keyboard on the fretboard. everything else kind of came together on its own.

after opening it up, i noticed that the circuit was capable of having sharps and flats. it was just a matter of wiring them in. my first idea was to have an A.R. generator triggered by the keys that modulates a vcf. it took a long time to make this all work. the one major problem was that there was no capacitor to switch in order stretch the note long enough to catch the end of the a.r. generator. all i could find was a short that held the note until the auto reset kicked in. and since the vcf sounds best when the keyboard is under clocked, the note would hold for like 2 minutes. after a bout two days of bread boarding, i decided that this circuit was a lost cause. it sounded really cheap anyway and it had a bad case of monophony. after searching my toy collection for a new direction, i found this:

despite its size, this keyboard is actually extremely compact.

this is the amplifier

the keyboard is 4 voice polyphonic, 10 rhythms, 10 timbres, auto accompaniment with 5 timbres on each bass and chord, record and playback, drum record and playback, 6 drum sounds, stereo amplifier, on and on and on.... and it sounds really really good for a cheap toy keyboard. its clocked at 3.58MHz. needless to say, there are too many function switches to fit on the guitar that i have, so i got an idea for a switch program pad:

coincidentally i found this at the bins the same day i found the guitar

i got 45 switches down to 15. the only problem is that you will have to have a sort of truth table in front of you to make it work. 5 of the switches will have led indicators for different functions. if i have enough juice left after everything else, i think i'll try to put stereo level meters behind the other 10.
ok, so now that i have a sort of plan and i have completely deconstruct and documented the keyboard, i can finally move on to my favorite part cutting up the plastic and fitting it all together.

template for hole

guide lines


littler keys

fits good

mazel tov

dirty hole

clean hole

switch pad holder

switch pad

with buttons




done for today

i dont think this will all fit on one page so i'm going to cut myself off here.