Category Archives: Pitch Resistor

Mods that use a pitch Resistor

The Madnoodle Circuit Bent Cell Phone

Strait outta Brooklyn our friend the Madnoodler sent this awesome stop-motion video of a toy cell phone getting bent. Imagine the look on peoples’ faces when you bust this out on the train. LOL. Being this close to Chinatown Cliff enjoys getting his hands on all kinds of crazy looking toys. Enjoy.

More information on how to score one here.

Creme Dementia’s Recipe for Circuit Bending the Protech Drum Toy RY-1286T, pt. 1

Greetings LoFiers! Tommy from Roth Mobot supplied me with a dupe of a toy I’ve bent before, the RY-1286T Protech Drum Toy. Tommy has the best toys.

I’m very fond of the Protech Drum Toy (or the “RY-1286T” if you read it’s most likely peeling label on the back), and it has special significance for me, as it was the first toy that I ever circuit-bent. With instruction from Patrick from Roth Mobot at a free workshop in 2005, I was able to find and figure out how to wire a pitch bend and a noise/buzz bend. Thus was born the Drum Invader, and it remains one of my favorite projects to this day, here it is in action:

The toy pretty much looks like this when it’s not bent, minus anything silver on the outside you see in the video. There are no star stickers, either

Here’s a picture of the circuit board of the Protech Drum Toy that I bent. It’s followed by a schematic drawing of my bends, and an explanation of these bends.

Circuit Bending Protech Drum Toy

The Bends Explained:

A nice pitch sweep can be attained by soldering a 1M potentiometer in the configuration shown, using leads from the right sides of resistors R3 (center lug), R1, and R5. Nicely responsive body contacts can be installed using those same points. What really makes this toy sing, though, is the noise/buzz bend. By connecting the top (-) leg of C3 to J7 on the board, you get a loud buzz. By varying the components between these two points, you can control the timbre and volume of the buzz. I used a 15k resistor and a 473 capacitor to get two different buzzes. Try some other components! These buzzes are, for some reason, affected by the pitch bends. This essentially gives you two different wave forms that are pitch-controlled by the potentiometer and body contacts. The most interesting tones result from masking the the drum tones with these noise bends; the rhythms created by the toy “modulate” (not sure if this is the correct term, but you get the idea) the buzzes, creating rhythmic buzz “melodies” out of the drum beats.

Circuit Bending Protech Drum Toy

So, you may ask, why am I re-opening this toy now? For starters, some joints were poorly soldered and it’s beaten up from touring. Also, despite its excellent bending potential, this isn’t the most well-designed toy on its own; the small buttons that allow you to record patterns for playback and select rhythms and drum pages have a tendency to stick down and the on/off switch has a tendency to get really staticy. I think it’s ripe for a re-house and I think I may do the both of them simultaneously, creating one Amalgam of the two toys. So, why not document my progress for all you happy people?

We’ll call that Part 2.

Creme Dementia’s Recipe for Bending the Sesame Street All Star Band by Golden

Greetings all you people out there in Internet Land! This is Austin, aka Creme Dementia, and this is the first of hopefully many posts that I will be making for I’ve been circuit bending for about 3 years now and this is probably completed project #12 or so. I was introduced to bending by Patrick of Roth Mobot, while living in Chicago, and through him I have met many other benders. Daniel, aka Spunky Toofers, inspired me to start tackling obscure toys, ones that I haven’t seen bent much or that are just pretty whacked-out to begin with. The Sesame Street Keyboard is a good example of a pretty “whacked-out to begin with” toy, and the bends that I have found make for a lot of fun with the toy. I have come across 2 of these toys in my thrifty adventures; with the help of a third from eBay, I was able to Frankenstein-together the finished result you see. If you take the precautions I list in step 1 and solder quickly, I think you will probably only require 1 of these toys to bend it as I have.

I wrote this in a step-by-step manner in an attempt to make it accessible to beginners and pros alike. If it’s TMI, so be it, it’s better then TLI. My custom paint-job was done by splashing red nail-polish across the surface and adding several coats of clear-coat (I masked off the “On” button and keys with masking tape and newspaper). I did the eyes on the Sesame Street Characters in a similar manner with white nail-polish, markers and clear-coat. To mount the PCB buttons, I made a paper template and marked and drilled the holes for each leg for each button. I then soldered two leads to each, fed the leads and the legs into the holes, and put a dab of JB Quik Weld epoxy putty under each button to hold it on securely. Otherwise, this is all pretty simple, save for de-soldering. I’m sure you could creatively skirt having to desolder anything in this project, but I found it made things easier for me. I enjoy desoldering and its a good skill to learn if you haven’t yet. Treat yourself to a desoldering pump, it’s a great gadget to have around.

Alright, so here we go:

The Sesame Street All Star Band Unmolested:


Bending The SSASB

1) Before you open the toy, here is a list of some key precautions and some notes on my bends; read these instructions thoroughly before you get started. There are two shorter screws in the outer case, those go in below the numbered rainbow keys. A good way to hold onto your screws, as taught to me by Patrick of Roth Mobot, is to stick them to the toy’s internal speaker, but I’d get a container for them if you plan to have the toy open for any more than a day.

There are several ribbon wires and plastic membranes with printed traces inside the toy, be very careful not to bend or break these, as they could easily disable the buttons. I went through 3 of these toys before coming out with the finished product, and I think one the problem I encountered may have been from unknowingly breaking one of the wires in the ribbon wire. I encountered a membrane breakage in another toy, the Alphabet Pal (Fuckapede… see my MySpace page. Also, I do not give specific capacitor values for the last bend in these instructions; the values you could choose are rather open-ended. You’ll want to either experiment with a capacitor substitution box to find the values you want or experiment with capacitors that you have on hand. All the values I used were below .22 uF. Also, there is an auxiliary battery compartment with button cell batteries under the main circuit board. I removed these batteries and the leads traveling to it; I assume they were put there to power the toy at the point of purchase. When you load in AA batteries, the batteries push open a switch that breaks the connection to these auxiliary batteries, which are left to rot inside the toy. Most likely they are dead, as this toy is from the early 90s. Test them for charge and dispose of them properly if they are dead. Don’t just throw out those batteries, collect them and give them to the Lion’s Club or Radio Shack or Walgreens or the Fire Department or SOMEONE for proper disposal.


The SSASB Circuitry Bend Points

2) Looping –

Solder leads to pins 13 and 14 on the Sesame Street All Star Band 9124 Chip. Connecting these points will give you looping sounds. I wired a toggle and push button switch in parallel which would connect these two leads through a 47 ohm resistor, so that you can audition and hold loops.

I used solid core CAT5 strands to solder to the chip; they solder quickly. Quick soldering is key to avoid overheating and damaging the chip, which may also have been the culprit behind the problems I encountered in my first attempts at bending the toy.


My Control layout inside the SSASB Handle – It’s about the most open space you can find inside the toy.

3) Body Contact and Pitch Switch –

Desolder R6 from the SSASB Keyboard circuit board and retain it. Solder a wire lead to the remaining hole where R6 connected directly to C3. Connect a second lead to the loose end of this lead. Mount an on-off-on switch (SW1) in the case and solder the joint of these two leads to the middle terminal. Mount a body contact in the case and solder the remaining lead to it.

4) Pitch Switch Continued –

Attach the desoldered R6 to one of the outer terminals of SW1, and solder 2 wire leads to the other end of R6. One of these leads will connect back to the SSASB keyboard, soldered into the other remaining hole where R6 had been removed. The loose lead will connect in the next step.

SSASB Pitch Dials – I put these on the left side of the keyboard

5) Pitch Dials –

Mount three potentiometers in the case, two (or more) 1M potentiometers and one 5K potentiometer. Wire them in series, and add a 180 ohm resistor at the end of your loose lead and solder the other end at one end of the sequence of three potentiometers. At the other end of the potentiometers, solder a wire leading to the remaining terminal of SW1.

6) Capacitor Bay –

C3 on the SSASB Keyboard also affects the pitch when you connect other capacitor values in parallel with it; they drop the pitch into a different range. I added 4 PCB momentary buttons that put 4 different capacitors in parallel with C3. I would recommend experimenting with different capacitance values to get the sounds that you want.

7) Cut the positive lead from the AA battery compartment and add a reset switch (the looping can get crashy). Add an output and possibly a speaker switch and you are all done:



SW1 will give you three modes, Normal, Pitch Controlled, and Open. Normal mode is when you route it through the pole that R6 is soldered to. Flip it that way and turn the toy on. Press a sound, and during that sound, move it to “Open” (off). This will give you a long stream of noise that will last for quite some time. Move it to the last position, Pitch Controlled. Turn the 1M potentiometers so that they are at 0 ohms, move the 5K potentiometer to center and it should sound about normal. The 5K potentiometer will give you pitch control over the sounds above and below its normal pitch range, while retaining the integrity of the original sounds. As you add more resistance with the 1M potentiometers, it will get that shimmery quality of the noise stream caused by breaking the pitch circuit in “Open” position. While the toy is making a noise, hold down the looping button. If the sound starts looping, you can lock it on with the looping switch. Play with the controls in tandem, there’s quite a vast sonic range.

PLEASE, use this is as a jumping-off point and experiment, you might find a preferred layout or different control options.

The draw to me for this toy was its strange appearance and all its great factory tones, its easy dis-assembly and the fact that it’s made by Golden. More on that later. Thanks for reading, I will hopefully have some video of my bent toy for you to enjoy soon.

Da Da Da da-da DAH *SMASH* Oh Boy!

Yada Yada Yada Voice Recorder Circuit Bending

Yada Yada Yada Recorder in package

Here is something thats been floating around recently. Its called a Yada Yada Yada and is available through most of the retailers that carry toys. I found them in Walgreen’s and Target locally, however not online. Target has them for a sweet sweet low price of $6.99! There are several neat things about this recorder, one is that if you hold the Play button down it will continuously loop the sound, so wiring that to a toggle would be elementary. Second cool feature is the Warp Wheel, even though it does not affect the recording, the playback of the sounds can be pitched up or down to a degree. Now lets see what we can extrude from these boxes when we open them and look inside.

Unfortunately for me, the recorders I picked up turned out to be different revisions. Their function is identical but the board layout is much better in Rev. A UPC 69477, so look for that one in particular not 69460. Both versions of the board and their mods are posted below. Mainly I was interested in finding a pitch down for recording, because that would allow you to record longer loops, while loosing quality and gaining tasty aliasing distortion. The components are all SMD so its virtually impossible to unsolder anything, instead traces can be cut in points indicated on the diagram to allow for Potentiometer substitution of the resistor values affecting Playback and the Recording speed. I used 1 Meg Linear pots and in the higher ranges its a little difficult to control the pitch without it increasing very rapidly compared to the rotation of the knob, still works very well though. Do not try to remove the Warp wheel potentiometer, its in there for good and will be more hassle then its worth, all while risking to snap the board in half. Instead just cut the trace leading out of the single pin on the right. I would even go as far as leaving all the original wires attached because they are covered with some sort of rubbery glue. The original case is very durable and handy, but there is absolutely no room for all the components, so re-case is a must. When hooking up the microphone observe the polarity, logic says it shouldn’t matter, however if it is backwards you will only get noise in. The coin type batteries are also not practical so consider using a LM7805 Voltage Regulator to provide the +5 Volts for power. Should be enough to juice several units at once.

Currently I am in a process of building a looper device with 3 of these units, so far so good and lots of things I had to learn the hard way, like the part about removing the Warp Wheel and having to deal with a snapped board. As always I cannot be responsible for you ruining your stuff, so don’t blame me if you mess up, the mods worked for me, but they are in early stages and may be updated at any time. Enjoy and provide feedback. Thanks.

Yada Yada Yada Recorder Modifications yada yada yada recorder 69460 Board
Here is another place to get similar samplers wholesale for about $2.50 each. Roughly the same function with a different design, plus a bright LED! The internal circuit may be totally different however, anyone has pictures of the insides?

Adding Body contacts to toys

body contact circuit bent elephantcircut bent body contactbody contacts circuit bent

Body contacts can make the simplest of bends sound really cool. But adding the contact points to a pitch resistor of a toy may be a mystery to some circuit benders. There are two ways to add these contacts to the casing of a toy. One is documented in the Gijs’ nice tutorial depicting the process of using a hot soldering iron to heat and melt the nail all the way through the eye never to less, of a plastic elephant. The Geij’s webpage calls for “chair nails”, however those can also be called “tacks”, “upholstery nails”, or ” furniture nails”. Sometimes the caps on these nails may need to be sanded because they are covered by clear coat paint, which would impede the contact with the skin. That is one way to get the job done, but I often prefer a less dangerous method of using small drill bit to make a hole of same diameter as the nail. Then with a dab of glue to the underside of the cap the contact is secured. This later drilling method eliminates any possibility of burns, unless you were use your finger to hold the contact in place while soldering the wire to it. As well as keeping the soldering end of the mail clean from toxic plastic which may hinder soldering and create nasty fumes. I guess it all boils down to what tools you have available for the project. Thanks to Karl for sending this link.