Category Archives: Good Ideas

Spunkytoofer’s Open Source Circuit Bent Interface

by Daniel Park

There comes a time when it seems every circuit bender hits a wall. I’ve been looking at the wall for a long time and no matter how many times I looked at it the only solution seemed to work with and learn the MIDI protocol.  In short MIDI is a digital protocol developed in the early 80’s by the likes of Dave Smith, Yamaha, Korg, Roland and other big synth manufacturers at that time. So control information and the synths had a standardization in order to communicate with each other between different manufacturers of synthesizers and controllers.

There are a lot of instruments that are circuit bendable that are MIDI capable. Unfortunately some of these MIDI capable instruments are not implemented very well with the protocol. Fortunately there are great devices by companies that really took MIDI and implemented in such ways that offer extremely detailed control over sound that is useful to musicians, sound designers and composers.

We are all familiar with circuit bent toys, they are cheap, safe to work with, and great to learn on. Some can produce a very surprising type of audio output from circuit bending. More often then not if you see a circuit bent performance by a circuit bender: their table is  full of many different toys. This variety is often mixed in real time to produced a shifting array of unusual sounds.  I’ve found each toy is like a “patch” which typically any musician using MIDI can scroll through a lot of patches during a performance. That is only possible through digital interfaces.  As a musician and circuit bender that has lugged around many different bent devices through many city streets, transportation systems, and airports I can say that this is very unpractical for non-benders and professional musicians to carry around many different bent instruments for the sake of having different “patches” during a performance.

Professional digital synthesizers that are implemented well over MIDI will offer a modulation matrix, several MIDI channels (16-32 different voices) of different programmed sounds to play at once with each sound having precise control over each sound’s parameters and triggering. They will allow precise detail in editing and how your control information interacts with customized bent sounds.

When we look at instruments without MIDI we are looking at the device itself and the bender’s hardware designed interface. Often these are strewn with fragile components located on odd shaped enclosures with an interface that makes sense to the bender but often can be very confusing to anyone else. Once the interface is made there is no other way to communicate with the device with your controllers and other equipment in the studio. Depending on the bent interface you are limited to the controls it offers. Whether its a homebrew sequencer or a bunch of switches, a clunky patchbay with lots of cables, you as a musician would have no say in how to communicate with the instrument or whether or not you prefer the patchcables, tons of switches, etc.. unless of course the musician would choose to DIY which is ultimately the best way to approach circuit bending imo, in your own way.

The problem is that I circuit bend professionally and I’ve been listening to complaints of professionals in regards to circuit bent instruments: they’re unstable, hard to travel with, I can’t integrate my existing controllers with the instrument, they are just toys that are severely limited. In response I decided to work with rack synths because they can be racked safely without damage during travel and the ones I’ve been working with are true professional instruments. All the bends are  informed by correctly addressing each chip to ensure stability and by not cross bending any chips on the build.

This is a recent release by Spunkytoofers Electronics called the Wavecaper. A circuit bent Alesis QSR Quadrasynth. It features extensive MIDI implementation and a deep synthesis archeticture as well as a comprehensive effects processor and a fully editable drum synth. With this design I wanted the entire bent interface under MIDI control. Any MIDI source: MIDI cc’s, program changes, tempo synch, MIDI machine commands, notation can be routed to any destination on the circuit bent interface via sysex programming. The onboard modulation matrix on the Alesis Quadrasynth has 6 source/destination for the synthesizer itself, 2 source/destination for the fx processor and the added MIDI circuitry for the bent interface adds another 12 source/destinations. In total you have a 20 source/destination modulation matrix. Probally one of the largest I’ve seen on a MIDI controlled hardware synth.

The circuit bent interface features two patch bays on a bank of rotary switches. One patch bay is 10 points dedicated to the effects processor bends while the other patch bay  is 24 points dedicated to the oscillator bends.  With rotaries you can get creative and efficient. No more massive amounts of drilling for point to point patch bays. With rotaries you can select your bends, stack your bends so quickly that if you are sending the rotaries sequenced information you can custom circuit bend your oscillator waveforms, effects and the sample rate on the fly. This is somewhat reminiscent of wave sequencing although this is definately much more unusual and bizarre and completely open to programming and free sequencing and control.

Rather than go into details of exactly how I bent this I want to share some amazing little creations by other benders. These are little plug ins that circuit benders can use rather then develop their own circuitry that is time consuming.  Following in the spirit of circuit bending’s immediacy I find these tools exceptionally invaluable.

The first one is by the owner of this blog, Getlofi.  Alex has created the LTC1799 oscillator kit which allows you to replace the clocks of various functions on devices and control them under variable controls like knobs. in my implementation of the circuit bent Quadrasynth I have the LTC1799 controlling the overall sample rate. The sample rate is controlled via a knob or switchable to MIDI control.

The second device is by Highlyliquid called the MPA, it is a decoder kit that offers potentiometer control in ranges from 10k, 50k or 100k. I have the mpa controlling the LTC1799 kit. Since the LTC1799 offers such stable control and the MPA handles very dense midi information without any hitches these synch up perfectly with each other.

The third device was critical. Sometimes if you do not have true mechanical switches you will not get a proper bend. Any amount of capacitance, resistance, and electronic leakage into the contacts you wish to bend can cause a bend to not sound right or even make the instrument less playable!!!  I tried building my own circuits for quite awhile and spent much more time then I like trying to develop a circuit but the solution and the life saver was highly-liquid msa-r kit which has 8 reed relay switches under midi that offer true mechanical connections that are electronically isolated.

These products allow you to get to your intended results much quicker as a bender. Just like when we approach bending to get quick results over existing devices we do not have to develop deep programmable synthesizers ourselves and do everything ourselves..with these kinds of resources availble to us we no longer have to stare at walls, but can now focus back on what I hope is what originally got us into this circuit bending mess in the first place. The music!

more information can be found here:

Modifying Kaossilator Touch Pad Area

nebula_girl_kaossilator.jpg NebulaGirl shared this interesting photo a while ago. Her Kaossilator got gashed at a show and needed replacement of the outer membrane, thankfully the sensor sheet was not damaged. She was able to customize it with an old flea market photo and a vinyl over sheet. Plays just fine! Great little hack for those not afraid of taking their Kaossilator apart.

Modified Jaymar Toy Piano

by Austin Cliffe/ Creme DeMentia

Jaymar Toy Piano with Piezo Pickup and Removable Back by Austin Cliffe

Like many of you who are reading this, I spend a lot of time in thrift stores.  I have come across some older toy pianos in my thrift store adventures.  Toy pianos are actually pretty serious and widely used musical instruments.  They have a very distinct sound and you’ll be surprised how often you will hear them used once you recognize their timbre.  They are also somewhat valuable and sought after instruments, believe it or not.

When I bought these toy pianos, it was with the intent to install a piezo-electric pickup in them and resell them, since I had so many discs for making Bottle-Cap Contact Microphones.  I was intrigued to see that Nick Heimer, who I had met at Bent Fest Minneapolis 2007, had a similar idea and brought the resulting devices with him to Circuitastrophe;  his toy pianos were not only equipped with piezo pickups, but also had bent delay circuits bolted to them that would process the sounds coming from the pickup.  They are very bizarre-sounding, beautiful instruments.

Toy Piano with Circuit Bent Delay by Nick Heimer

Adding the pickup and output to my toy piano was relatively easy.  I found a good spot on the backboard to attach the pickup using a stethoscope, then glued the piezo disc in place with epoxy, finally covering it with a protective layer of Plasti-Dip.  The piezo pickup runs directly to a 1/4″ mono jack, which I recessed into the back panel.

Jaymar Toy Piano with Piezo Pickup and Removable Back by Austin Cliffe

Jaymar Toy Piano with Piezo Pickup and Removable Back by Austin Cliffe

Initially the Toy Piano didn’t play quite right, I had to diagnose the problem after taking it apart.  Toy pianos work similarly to regular pianos; instead of the hammers hitting strings, though, they hit corresponding tuned tines.  The comb of tines is mounted directly to the back panel.  The problem with my toy piano was that the back panel was installed crooked at the factory and not all the hammers were hitting their corresponding tines. I pulled out the factory-installed staples, fixed the alignment, and screwed the panel back on correctly.  In fixing the alignment of the back panel, I had the idea to make it removable so that you could play the tines however you like when the panel was removed.  I achieved this with hanger bolts and wing nut accompanied by a handle.

The idea of playing the insides of a piano is nothing new, and this project reminded me of two avant-garde composers of the 20th century, John Cage and Henry Cowell.

John Cage is probably a name you know;  did you know he composed pieces for toy piano?  He also composed a piece called “Cartridge Music,” where the performers would use phonograph cartridges to amplify objects.  Piezo-electric discs are now often substituted for phonograph cartridges in performances of this piece;  Cage’s score provides specific times for when the different objects are to be played, but the choice of objects is left open to the performers.

Henry Cowell you might not know.  Henry Cowell developed a variety of experimental piano playing techniques in the early 1900s, one of which called for leaning inside the piano and manipulating the strings with bare hands to produce scrapes, howls and deep rumbles.  He employs this technique in a piece called The Banshee.  John Cage, like many other musicians, was inspired and influenced by Henry Cowell.  Cage also experimented with the insides of the piano, by putting bolts, eraser bits and other things in between the piano’s strings.  These inserted objects drastically changed the piano’s timbre and a normal piano could be prepared in this way by following his specific written instructions. Cage then wrote pieces for this new range of gamelan-like sounds coming from piano he had prepared.  This process can be undone and causes no harm to the piano.

For your enjoyment, here are some videos of myself and some friends exploring the sound capabilities of this device paired with some effects pedals.  The first video shows the piano being played normally, the second video shows the removable back being played.  As was my initial intent, this instrument will be for sale on eBay shortly after this article has been posted, simply search “GetLoFi Toy Piano.”

Adding Straps to your Circuit Bent Instruments


Have you ever wanted to add a guitar strap to your bent keyboard or other bulky noise making device? No problem, what you need is some Guitar Strap Buttons from, 24 of them for $15. Certainly helps if you are planning on jumping around a lot on stage or would like to have quick access to your sonic devastator. These also add a nice touch if you want to sell your device. Local guitar shops usually have these pieces of hardware for sale, especially if they repair guitars.

Halloween Parade Marched On…

Madison 2008 Circuit Bent Halloween Parade

Madison Wisconsin was witness to it’s first ever Circuit Bent Parade this past Halloween night. A gathering of experimental artists, whom all were circuit benders, paraded up and down Madison’s State Street, while crazy drugged out revelers looked on in pure confused form. One on-looker asked participant Igloo Martian “what are you together” as she tried to guess what inconceivable idea, from some inconceivable cult flick costume we were trying to replicate. Igloo simply said ” oh…were not together”. This set the mood thoroughly for a perfect night, as both the woman with question and Igloo broke out in laughter. You see, it was Halloween night. Nothing was supposed to make sense to those who gathered on the same street to be entertained by one’s own, or others, crazy filled minds. This was Madison’s night to let the freak out! The parade launched right at 9pm from Madison’s Memorial Union’s steps. The line consisted of Igloo Martian, and myself (life as number five.) We were later, our first trip down State Street, stopped by Frenanda (Useless Unknown Facts), a speak and spell toting, fashionable appropriate Image of The Life Aquatic with Steve Zissou. Neither Igloo or I had ever met her, so it was a pleasant surprise to meet another bender at such a cool time. Igloo offered to plug Frenanda into his traveling amp, which he already had the both of us mixed to grove. After plugging Frenanda in we were set to jam, marching to the beat and sounds of an obscure circus parade from some twisted 40’s animated picture show. Weaving our way in and out of the crowd of 1000’s that gathered, we were subject to many bizarre characters and situations, all in great fun, even the police…at one point. One man commented that “this was the best thing I’ve seen on State Street in a long time”, this was a true compliment as State Street is famous for the odd and unusual. After a few hours of continuous experimental jamming, we called it quits for the night, all leaving satisfied. Having had spontaneous dancers and cross dressing males burst out into tribal stride, we knew we had ripped it up as thoroughly as we could have ever dreamed. Not many pictures were taken, as we were to into the parade to care, and as those we asked to snap a picture were to drunk to even understand our request to snap a photo of us as we played. So I’ll leave you with the images your own thoughts can conjure of such a mighty event, and recommend you have a Circuit Bent Parade of your own in the near future. Maybe New Years Eve….