I’ve been more and more intrigued by electronic music, sparked mainly by covering an exhibit of designer theremins for IEEE Spectrum in 2013, adopted by watching documentaries for example 2014’s I Imagine Wires, which traces a brief history from the modular synthesizer. One notable cohort in the current electronic music scene would be the circuit benders. These individuals modify a variety of audio-enabled equipment, including children’s toys and digital keyboards, to create sounds certainly not intended through the designers. Then when I stumbled upon the Casio SK-5 keyboard [pdf] I’d received in my 14th Christmas lurking within my parents’ attic room, I pounced.
Released later, and targeted at more youthful players, the Casio SK-5 never was supposed to have been utilized by serious musicians. The laptop keyboard had only 32 “minikeys” sized for smaller sized fingers, also it could play just four notes concurrently. The SK-5 could mimic numerous instruments, nevertheless its killer feature was you could make your own instrument sounds through sampling audio (in a whopping 8-bit resolution).
Photos: Stephen Cass (4) I wired DB-25 connectors towards the Casio SK-5’s seem-synthesis chips and 32- key keyboard [top]. I designed a patchboard for that synthesis chips by mounting some RCA connectors inside a box that attaches towards the chips [second from top]. The laptop keyboard is controlled by an Arduino Mega using eight four-switch ICs [second from bottom]. To suit the circuit right into a reasonably compact box, I sandwiched the circuit boards [bottom].
I’d initially go about attempting to study SK-5, however i hit a wall when my educate-yourself-piano book introduced guitar chords. The 4-note limit managed to get frequently impossible to experience both guitar chords and also the tune of the song simultaneously. Consequently, my buddies and that i mostly used the SK-5 to do its preprogrammed demo tunes utilizing a fine choice of sampled burps.
Since that time, the SK-5 is becoming extremely popular among circuit benders. You are able to purchase one on eBay for less than US $100, and directions for modifying the laptop keyboard are often obtained online. (The fundamental principle is just to ground or mix-connect pins of the audio-synthesis chips.) You may either do that yourself or send your keyboard off to be professionally modded.
However these instructions generally demand ripping the SK-5’s built-in speaker. Instead go patch-panel connectors or switches wired towards the nick pins (to ensure that different bends may be used throughout a performance via patch cables or flipping switches). I needed to retain a choice of while using keyboard in pretty much its original condition and provide myself a choice of trying various kinds of bending systems as my interests developed.
The present guides also unsuccessful to resolve another pressing issue: I still can’t take part in the piano.
But after opening the SK-5’s situation and poking around for any bit, I recognized I possibly could solve both problems. Even though the SK-5 uses two 28-pin synthesis chips, most of the pins backward and forward chips happen to be interconnected. Eliminating duplicate ground and utility lines along with a couple of pins that didn’t appear to create any interesting results introduced me lower to 25 pins—which just is actually the right number for any DB-25 connector. And also the SK-5 keyboard is actually only a 32-button matrix keyboard that utilizes a 12-wire cable—four return wires and eight lines for that checking pulses—so I believed it might be simple to find away out to simulate key presses under computer control.
I created an opening within the situation from the SK-5 nearest towards the synthesis chips. Utilizing a soldering iron and a few wrapping wire, I connected the chips to some DB-25 and screwed it into position within the hole. I repeated the operation at the rear of the SK-5 for connecting the laptop keyboard cable. I Then closed in the situation and hang about building two boxes.
The very first box has two breadboards along with a patch panel with eight sockets on the top along with a DB-25 connector at one finish. The breadboards permit the patch-panel sockets to become wired to various synthesizer pins, and permit a choice of making semipermanent bends using jumper wires. Soon I’d all sorts of weird sounds appearing out of the laptop keyboard.
The 2nd box attaches towards the keyboard switch matrix. Initially I figured I possibly could simply hook the 12 matrix wires straight to digital pins of the Arduino 1. My plan ended up being to identify the probing pulses around the scan lines, and respond having a 5-volt signal around the appropriate return line, mimicking the matrix’s reaction to a vital press.
However the outcome was terrible. The Arduino simply couldn’t respond reliably enough towards the 1.9-nanosecond-lengthy pulses. Using hardware interrupts may have helped, however the only Arduino boards with sufficient interrupts readily available for eight scan lines operate at 3.3 V, as opposed to the 5 V utilized by the SK-5.
So rather I made use of eight 4066 ICs. Each 4066 has four switches that may be opened up and closed with a control signal. Using two perf boards, I connected the ICs towards the keyboard’s wires in order to digitally duplicate the switch matrix. Now i had 32 control lines to cope with, and so i ditched the Arduino 1 in support of an Arduino Mega. I mounted the Mega on the top from the box housing the perf boards. Powering pins around the Mega simulates different key pushes around the SK-5 without resorting to nanosecond response occasions: Even at its sloppiest, my software still beats the truth of human fingers.
By looping gradually through each pin consequently and listening, I could map each pin towards the note it creates. Writing software to experience music ended up being only a matter of converting written music to a range of bytes akin to the needed pins, having a couple of extra codes tossed set for items like sustaining notes or rests. I tested the machine using the “Hello, World” of electronic music—a couple of bars from the tune in the Mario game theme song.
This, obviously, is simply an ersatz reinvention from the MIDI musical control system. Real MIDI would allow me to download a variety of tunes to my laptop and play them with the SK-5 without laborious conversion. And actually you can purchase MIDI modification boards for that SK-5. What I’m really thinking about would be the options afforded by my system to create notes algorithmically, with choices driven by sensors put into the Mega.
This sort of factor produces seem that grouped into the abstracted arena of the subgenre of electronic music referred to as “noise,” which would be to, say, pop or classical music like a Jackson Pollack painting would be to a Caravaggio or perhaps a Van Gogh. Possibly fortunately in my wife and colleagues, there is a soundproof media room at Spectrum’s office that i can experiment in.
This short article seems within the May 2016 print issue as “Circuit-Bending a classic Casio.”
TOY #11 CASIO MT-100 Keyboard 1983 | HD DEMO
- Fred Payette: That sound at 3:50 ! I use it to play songs from the Sega Genesis's game Phantasy Star IV
- squeem geef: aphex twin MT1?? the arp at about one min in the song sounds like the bit at 1:18
- MicroKORGI: Hmm, drum intro for Combat Baby?
- JJ Wright: My very first keyboard! I mowed lawns and babysat until I had the — I think it was $40? maybe $80? — to get it from the local WalMart in 7th grade. I still have it, and as far as I know, it should still basically work, though I haven't put batteries in it to try in a decade or two.
- FRIEDHELM ERNST ESSER: i heared an circuit-bended one : AWFULL !!!!
this is so clear n realistic.
still luvezzz this thing…..
- OrangeJackson: My first synth back in 1984!
- XxX: Is the last sound (the repetitive one, electric guitar i think ?) from the casio (with vibrato effect ?) or is it an effect you've achieved with something else ?
- d vibe (swe): Sounds very much like their take on FM, .. .. I think it was called phase distortion, except for the drums that sounds very analogue 🙂
- MrShiffles: My MighTy 100 suffered various physical casualties over the years, but i kept it alive long enough to sample the rhythm/accompaniment section including the individual percussion sounds before it died…i wish i still had it to keep my SK-1 company :/
- setphaser: Love the casiotones with edit ability, the mt-65 is my baby.
- PSS-270 Casio-Core Music.: This is good.
- RABBIDGamfan: This is the synthesizer used in all the Homestar Runner toons.
- Illegalquantity: It sounds surprisingly nice.
- Fred Payette: I got this keyboard and a baseball mitt for 5$ in a yard sale two years ago ! The equalizer is a bit rusty but amazing keyboard
- Jack Tran: Thanks for the upload! You used some of the accompaniment in ways I never would have thought of! Always thought it was cheesy, but I didn't realize it was a good way to split the keyboard into two different keyboard sounds. Great demo. I wish this had come around when I got this keyboard 2 years ago. There were no demo videos worth watching for this keyboard on youtube at the time so I took a shot in the dark, walking 5 miles to get this thing off craigslist in San Diego. Turns out to be a great machine! I've always been confused about the sounds on this though, the organ sounds so analog. Do you know how this thing is party digital? I know the drums are all analog. They're the real centerpiece of this thing aside from the excellent equalizer that can work like a neat filter. Anyway, great upload! needed to be out there for this underrated casio! It's got some of the best organ and drum sounds! Great for dreampop! You can't get excellent analog drum sounds for a better price than this! Got mine for 30!
- Alvaro Faria: Não sei quanto vale, mas eu quero! hahaha
- Marcangelus1: Another hidden gem.
- FRIEDHELM ERNST ESSER: i still have it.since december 1983.was the first christmas gift from my wife !!!!!
great piece of music.the drumsets are incredible,and the rhythms are outstanding.this demo shows not 1% of the keyboards capability !!!!! thank you,for posting this.
- nobel 11: I picked one of these things under the Realistic brand. I love it. Especially the auto-accompany.
- synthartist69: This is what many of us learned to play on….. I learned on an MT68
- D10078: Surprised it's still working after all this time. No electrical corrosion etc.
- Arrayzable: Uuuh, I just love the sound of that!
- whatsuphotdog: LOVE those sounds
- Lachlant1984: This sounds a bit like something Kraftwerk would have used, I know they used a Bee Gees Rhythms machine thing in Pocket Calculator, but I wonder if they used one of these in some of their songs.