Circuit Bending For Novices

[Editor’s note – the next excerpt is obtained from the approaching book, Junkyard Jam Band, compiled by David Erik Nelson and graciously presented to Artist by No Starch Press. To purchase it, or for more information, mind to]

The Slinkiphone (Project 1) and Scratchbox (Project 5) hint in a fundamental truth from the modern day: there are numerous really neat sounds hiding within your toys and electronic devices. Opening cheap electronics and feasting around the sonic goo within is known as circuit bending. This type of exploration was pioneered by artist Reed Ghazala, the “;Father of Circuit Bending,” who happened across his first bends like a teen within the mid-1960s. Ghazala has tirelessly promoted the creative potential of musically upcycling electronic devices since. Within this project, you’ll get the ft wet with three entry-level bends.

Thrift stores, yard sales, and remainder bins are filled with electronic toys ripe for exploration. When selecting a toy to tweak, only use battery-powered toys, and watch peeled for older toys. Older toys are often constructed with largely generic components and provide more circuit-bending options than newer toys, which have a tendency to offload the majority of their functions to purpose-built microprocessors. That stated, bending new toys can nonetheless be quite fruitful. For instance, most personal injury protection-squeak electronic toys—like individuals proven in Figure 7-1—can generate big, wealthy sounds with impressive bass, however their puny built-in loudspeakers just aren’t to the task. Just a little bending can release everything good noise.

Figure 7-1: An array of circuit-bent instruments and toys. Note the black box around the keyboard and also the new bits alternatively three: the knobs, switches, and bare metal contacts let us tinker using the toys’ pitch and tone quickly, as the jacks let us amplify the output (and, within the situation from the megaphone, pump our very own signal in to the input).

Warning: Only bend battery-powered electronics! Household batteries are usually safe to utilize: they’re small , supply relatively low voltages and currents. For instance, a 9-volt battery will reliably supply under 100 mA and shouldn’t hurt you (unless of course you attempt to swallow it, I guess). In comparison, the AC electricity offered by your wall outlets is harmful, offering a large number of occasions just as much current and also over 100 occasions the current—120 volts and ten to fifteen amps. Wall current can certainly burn your home lower and can certainly kill you because of the chance. Nothing within this book is supposed to ever encourage you to definitely focus on any electrical device that connects to the wall!

Hear my circuit-bent keyboard for action within the samples at


Build Time

About half an hour for an hour, with respect to the toy and quantity of modification


  • A typical soldering package (See page 340.)
  • An array of screwdrivers (Should you not curently have them, I would recommend some jeweler’s screwdrivers, which often includes # and #1 Phillips and 1.4 mm, 2 mm, 2.4 mm, and three mm flathead motorists.)
  • A little flathead screwdriver for prying open plastic cases
  • Several teams of jumper clips (You should use insulated test leads, which seem like small jumper cables. Pricier small-clip hook-style jumper wires are better.)
  • An electrical drill with bits (To modifying the toy’s situation to support new jacks and switches.)


  • Battery power-operated toy or instrument you would like to vivisect
  • Two normally on momentary pushbutton switches, also known as normally closed SPST switches (For additional on switches, see “;Switches” on-page 338.)
  • A 1M ohm variable resistor (Variable resistors will also be known as potentiometers or containers see “;The Gory Details: Audio Taper versus. Straight line Taper” on-page 327.)
  • A fistful of other resistors, potentiometers, switches, brass screws, metal knobs, and so forth
  • SingleOrfour-inch mono phone jack, also known as an instrument jack
  • 24-gauge insulated hook-up wire (22-gauge speaker wire is okay, too. It’s stranded like hook-up wire, only slightly thicker.)
  • Small boxes to support the additional jacks, switches, and containers you’ll increase instruments (Any thin-walled parcelled up is going to do hobby shops frequently carry a number of “;enclosures” and “;project boxes,” such as the one connected to the keyboard in Figure 7-1. See “;On Enclosures” on-page 214 to learn more.)
  • Two alligator clips (Those proven in Figure 7-12, frequently known as small-hook clips, tend to be simpler to make use of when clipping into commercially created circuits. Individuals pictured are American-made “;E-Z-Small-HOOK TEST CONNECTORS” from E-Z-HOOK, Digi-Key parts #461-1013-ND and #461-1014-ND.)
  • 22- or 24-gauge bare bus wire (This really is uninsulated solid core wire. Since you only need a couple of little snips of bus wire with this project, you will get away with utilizing a scrap of wire, a leftover bit snipped from the component lead, or perhaps a bit of a paper clip.)

Figure 7-2: Tools and supplies

Three Fundamental Circuit Bends

After you have a couple of toys selected out, we’ll customize the output with the addition of singleOrfour-inch jack and optional momentary mute button, use resistor-based bends to securely monkey using the circuit’s internal clock, and give a power reset to create happens for advanced circuit exploration. We’ll finish off having a brief discussion of methods to package a finished circuit-bent project.

Most toys, especially newer ones, haven’t much spare space inside to support new jacks, switches, and variable resistors, so the most crucial preparation would be to consider how you can package everything when you are done adding new functions. Final packaging could be tricky, but it’s not even close to impossible consider it as being another outlet for creativeness. Also, bear in mind that there’s nothing stopping you against adding off-board expansion modules or entirely repackaging the toy’s electronics inside a bigger situation.

While you’re pondering your packaging options, pull the batteries from your toy and take away all of the screws you’ll find. Remember to consider screws hiding under stickers and towards the bottom from the battery compartment. Then, pry open your toy’s situation and see whether you’re coping with a classic or new toy. If you are unsure, take a look at Figure 7-3. The left panel shows part of the guts from the 1980s electronic toy keyboard the best shows the whole circuit board from the newer McDonald’s Happy Meal free gift toy (particularly, a 2010 Alvin and also the Chipmunks speaking Theodore).

Figure 7-3: The older circuit board (left) has numerous large, easy-to-identify components. The current toy’s circuit board (right) is a lot smaller sized (the whole board is smaller sized than my thumb) and it has couple of components, that are harder to differentiate.

The older toy is composed of many generic, discrete components that you will recognize from building your Android Voicebox (Project 6) or any other electronics projects: resistors, capacitors, variable resistors, diodes, LEDs, and integrated circuits (ICs). The brand new toy, however, has couple of recognizable components and rather sports that mysterious black blob (within this situation, it’s within the upper-right corner). That blob hides just one, highly specific micro-processor that replaces the majority of individuals discrete parts. Newer toys usually depend on such black-blob chips. To increase the task, the couple of discrete components during these newer toys will often be really small surface-mount components, for example resistor R1 and capacitor C1 in Figure 7-3, instead of the standard components you’ll upgrade on projects within this book. Surface-mount components are not as easy to differentiate than standard components and, because of their small size, tend to be more of the discomfort to utilize. That stated, even on newer toys with small circuits made up of surface-mount components, altering in the output remains an easy operation that greatly expands the toy’s audio palette.

Customize the Output

I strongly advise adding 1/4-inch jacks to each toy. I’ve regularly been delighted through the breadth and depth of sounds the junkiest toy provides once it’s correctly amplified or pumped into commercial or homebrew effects. I additionally strongly advise utilizing a high-quality jack: the jack will get jerked around a good bit, then one nice, just like a Switchcraft, will endure that for several years. The least expensive of cheap jacks—which are usually standard on consumer-grade electronics as well as midgrade guitar amps from big-name manufacturers—can start getting loose and noisy after only a couple of several weeks of standard use. Very annoying. A Switchcraft will remain sure and steady for many years.

Within this section, you’ll use 2 kinds of mono phone jacks: normal and switch jacks. The standard mono jacks, proven in the far left of Figure 7-4, is going to be familiar if you’ve seen or handled an instrument, amplifier, or stomp box. The switch jacks, proven in the centre as well as on the best, really are a little special. When there is nothing connected to a switch jack, the signal would go to the device’s built-in speaker. Whenever you plug something in, the interior speaker is disconnected, and also the signal is routed rather towards the exterior amp. If you are intending to switch the toy’s original speaker altogether, make use of a normal mono jack. If you wish to keep your original speaker out on another care the built-in speaker makes seem even if your toy is connected to an amp or effect, a normal jack continues to be fine. However if you simply want the toy to instantly mute the built-in speaker whenever you plug to your amp or effect, then you need to use a switch jack.

Figure 7-4: A typical mono jack (left), a normal switch jack (center), along with a Switchcraft 112AX switch jack (right)

Step One Select a jack. For common jacks, I’d opt for the Switchcraft L11, proven in the far left of Figure 7-4. It’s Digi-Major factor #SC1085-ND or Mouser part #502-L-11. (Check both, as there might be a reasonably large cost difference, especially when you operate in handling and shipping.) The center jack in Figure 7-4 is really a Switchcraft 12A, the switchable form of the conventional Switchcraft mono jack. This open-style switch jack is great because its internal mechanism is entirely visible, which makes it just a little simpler to know if you are a new comer to electronics. Its only drawback is it looks a great deal just like a standard mono or stereo jack. For those who have a jumbled box of mixed jacks (when i do), it’s very easy to miscount and obtain midway via a project before realizing it’s not necessary the jack you thought you’d. Because of this, my preferred switch jack may be the partly enclosed Switchcraft 112AX, proven in the far right of Figure 7-4. It’s exactly the same jack utilized in the Plasti-Pickup (Project 2), Digi-Major factor #SC1316-ND or Mouser part #502-112AX, and it is super easy to differentiate from mono and stereo jacks.

Note: Steps 2 through 4 describe how you can give a common jack, while Step Five describes how you can give a switch jack.

Step Two Decide whether you need to keep the toy’s existing speaker or amputate it. If you opt to lose the present speaker, this mod requires just the two steps proven in Figure 7-5: snip from the speaker, solder one wire to each one of the two lugs on the standard 1/4-inch jack, and you’re done. The black speaker wire typically would go to the jack’s ground lug and also the red wire to the tip, however that rarely makes any improvement in these situations. (For those who have no clue exactly what the tip and ground take presctiption a mono phone jack, switch to “;Quarter-Inch Phone Plugs and Jacks” on-page 337, where they’re highlighted. If this sounds like brand new for you, see “;Soldering” on-page 346.) If you’ve made the decision to help keep the speaker, proceed to Step Three. If you would like to include a momentary mute, skip to Step Four.

Figure 7-5: The unmodified toy with speaker in position (left) an amputated speaker substituted for a jack (right)

Step Three If you wish to keep your original speaker, the fast-and-easy option would be to jumper a jack in, as proven in Figure 7-6. To achieve this, just cut two lengths of insulated wire, strip and tin both sides of every, and solder one wire to every lug around the jack. Now, solder one wire to each one of the two terminals around the speaker. Around the upside, this method is fast and simple, and also you retain the opportunity to play anywhere while adding the opportunity to harness amps and effects. Around the downside, even if you’re connected to an exterior amp, you’ll have the built-in speaker making noise, that might prove annoying, particularly if you use mics to isolate your various instruments for recording. Seems like annoying, switch to Step Five. Otherwise, you’re done!

Figure 7-6: A “;jumpered” auxiliary output jack

Step Four Adding a pushbutton momentary mute enables you to definitely rapidly cut the signal towards the speaker and output jack. Just snip the positive speaker wire, that is usually red and it is frequently linked to a + sign up the circuit board, the speaker itself, or both. Then, use a normally closed—that is, normally on—pushbutton SPST switch between your circuit board and also the speaker and output jack (see Figure 7-7). Whenever you contain the button lower, the output is silenced. Release the switch, and also the speaker immediately returns online.

Note: When the board and speaker are unmarked and also the wires are otherwise identical, don’t worry about it. Just pick one wire to think about positive and stick to that. “;Positive” and “;negative” are nearly always arbitrary distinctions with regards to small loudspeakers in battery-powered toys.

Figure 7-7: An auxiliary output having a momentary mute

A mute offers lots of neat sonic options, enabling you to chop and punctuate the toy’s noise. For instance, rhythmic momentary muting is really a answer to the stuttery gate and transform effects famous electronic dance music. Even though you don’t decide to add an output jack, a momentary mute continues to be an enjoyable mod for just about any electronic noise toy.

You ought to be done installing your plain jack at this time, so either proceed to the following mod, “;Explore Resistor Bends” on-page 104, or continue reading through Step Five to learn to give a switch jack.

Step Five Should you not want the interior speaker to experience whatsoever occasions, make use of a switch jack. Around the partly enclosed Switchcraft jack I’ve specified, the corner lug may be the ground connection, also it makes connection with the barrel, as opposed to the tip, from the plug. The lug farthest in the ground lug connects towards the jack’s tip and carries the audio signal. The center lug connects towards the internal switch.

To wire this switch jack, first snip the positive speaker wire in two. Solder charge attached to the board towards the tip lug of the jack. Then solder charge attached to the speaker towards the middle lug. Solder another insulated wire in the jack’s ground lug to another lug in your speaker, as proven in Figure 7-8. Observe that this switch jack layout—with the floor and tip opposite one another and also the switch connection within the middle—is likely not universal. To find out which lug is which in your jack, either look into the datasheet (the website in which you purchased the part must have it published in the web based product listing) or perform a little guessing and checking. You may also give a momentary mute here, if you want. The process is exactly like it had been using the common jack, outlined in Step Four.

Figure 7-8: A finished switch jack output

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  • Igor Amokian: looks like you have plenty stuff to bend, I have seen your vids….hahaha
    That pedal ROCKS!!!!
  • Igor Amokian: Oh, I was going to hook you up on something to work on, you said you need more things to bend.
    No worries…I’ll keep it and work on it myself.
    hhhaaahahahKeep in touch.
  • Igor Amokian: Thanks man, I have something boxed up for you.
    I will mail soon.