CIRCUIT BENDING ... Mini forum in a single thread !!!

[_oswald]

i read that if you put a capacitor before the output jack it stops high frequencies,but i don't know where exactly,i'm connecting the + - from speaker to the jack-out.can any one help?
also,is this a good book? 'Circuit-Bending: Build Your Own Alien Instruments',i noticed it's u.s. based,would it still be useful for a pommy?

Try the - connection to the tip and the + connection to the sleeve. I'd also wager that you can just put the capacitor in-line, and I'd suggest on the - lead.

The book is a good introduction to everything. Reed is also a really talkative guy so if you have a question or concern, feel free to email him. Last I knew, he was busy working on a book about birds, but he's responded now and again and he's a helpful and friendly lad.

[spacedad]

Try the - connection to the tip and the + connection to the sleeve. I'd also wager that you can just put the capacitor in-line, and I'd suggest on the - lead.

ah,i was putting the + - the other way round,i haven't got any croc clips atm,so it's a bit awkward to try things...on the lead? on the + or - line?
i might get the book cos there's a cheap one in amazon and it's my birthday soon. i mean.you gotta start somewhere.

[_oswald]

Try the - connection to the tip and the + connection to the sleeve. I'd also wager that you can just put the capacitor in-line, and I'd suggest on the - lead.

ah,i was putting the + - the other way round,i haven't got any croc clips atm,so it's a bit awkward to try things...on the lead? on the + or - line?
i might get the book cos there's a cheap one in amazon and it's my birthday soon. i mean.you gotta start somewhere.

I'd put the capacitor on the - wire, between the 'board and the jack. So it'd be like this:

Board (-) ======= (Capacitor) ======== Jack, Tip (-)


Oh, and ===== means 'wire'. I tried to draw it ASCII style and the spaces didn't come out right :/

[spacedad]

thanks,it's still not working,i'm using a ceramic cap,should it be an electro?

[aciddose]

in order to have a filter as you want you need two things:

1) resistance.
2) capacitance.

this combination is called - reactance.

hz = 1 / 2pi * capacitance * resistance

if resistance is zero, your cutoff will be infinite, meaning you get no effect.

what you must do in order to form a filter is connect

signal -> resistor -> capacitor positive -> output
capacitor negative -> ground

however, this gives you one major problem: you now have that impedance on your output. the maximum output impedance of a circuit should be 10k for line level signals. in order to get our output impedance 'Zout' to an acceptable level we need a buffer.

we can use an opamp for this which i recommend as the simplest solution for a beginner:

capacitor positive -> non-inverting opamp input -> opamp output -> inverting opamp input

take your buffered signal off the opamp output + negative (inverting) pins which are tied together.

bending _does_ require knowledge of electronics if you want to get anywhere beyond throwing some random components and shorts around, potentially doing nothing at all.

you should get a few things:

30 gauge (or so) wire. try to get solid core for bending, it'll be easier to handle and solder. try to get a few colors like black, red, blue, yellow, green, white. we're talking $30 for this.

solder! get leaded solder which is much easier to use than the lead-free types. use 60/40 rosin core 62mils, and see if you can get 40 or 33 mils too. thicker solder is good for jobs that need lots of solder like pots/sockets and other stuff with lots of metal. thinner solder is better when you're soldering components.. generally you'll want to match the pad/trace size to your solder size. typical component pads are 32mil, typical larger pads like for pots are 62mil. mil = thousandth of an inch. 1000mil = 1inch.

flux!!! <-- most important. get corrosive flux like zinc chloride.

wire/other brushes: hair/poly for soaping, brass for cleaning flux/dust, steel for polishing solder joints.

soldering iron: you'll obviously want one of these. get at least a 60w and make sure you get one where you can easily buy fresh tips. do not get a iron that uses an uncommon tip type. wedged tips are easiest to use in general, rounded/pointed tips are ok. avoid the sharp tips at first. (those are for smd reworking and that kind of thing)

buy a cheap electronics book and read wikipedia pages on electronics. what you need to learn are the basic functions like ohm's law and so on. sort of like how you need to learn some of newton's laws to do basic physics models.

[spacedad]

thanks aciddose,some good tips.
i read about adding resistance too,and finally got it to sound ok,reconnecting the speaker seemed to make a big difference.i used an electro cap,about 50u(or whatever) and 10k res.i put a pot on it too,then sent it back to the speaker.it was good fun just experimenting,like synthedit,but real.
i've been soldering leads and stuff for a long time,simple things like a headphone splitter box in an icecream carton,my best was a telephone mic in a parmesan tub.beyond that i don't have clue,the money,the time to do much.every now and then i get a chance,so help appreciated.

i was trying to get a led to light up for my little boy using a AA battery and res but it wasn't happening,think it maybe needs 4 AA's? i'll get there, a bench would be nice,i'm on the dinner table atm,the kids pulling at the wires and the mrs complaining,hardly ideal.oh,well i'll be old soon and i can have a shead.

[aciddose]

the average LED wants about 25ma, i believe. so, you need ohm's law.

current = I
voltage = V
resistance = R
capacitance = C
inductance = L

I = V/R

so, say we have 1 aa battery. that would make v = 1.5. the V part needs to be from the "entrance" of the circuit to the "exit". in this calculation we're concerned with the V across R. we know that the LED will have a "diode drop" called Vac (voltage annode-cathode) or Vf (forward voltage). in a red LED this is about 1.5v - uh oh.

so, we have:

bat+ -> R -> LED -> bat-

let's figure the voltages across here:

bat+ 1.5 -> R 1.5 -> 1.5 LED 0.0 -> 0.0 bat-

this means I (current) is going to be zero.

ok, so let's do two AA bats:

bat1+ 1.5 -> bat2- -> bat2+ 3.0 -> R 1.5 -> 1.5 LED 0.0 -> 0.0 bat1-

ok, so now we can put 1.5 into our ohm's law calculation:

I = 1.5 / R

we need I = 0.025, so let's select R:

1.5 / 60 = 0.025.

so we need two AA batteries, one 60ohm resistor (can use 47 or 100, will just be slightly brighter or darker) and the LED. remember that different LEDs will have different Vf, so you'll need to check the packaging or data-sheet to find out how much Vf and I are for your LEDs.

[neg] -> [pos] -> [47ohm] -> [led] -> [neg] -> [pos] -> [back to other bat neg]

[spacedad]

wow,thanks! brilliant info.
gonna have to take another trip to maplin....now what am i gonna do with that single AA battery holder.

[_oswald]

wow,thanks! brilliant info.

I second that. I've never been that good in the whole 'ohms law' thing and his explanation and application was damn good.

Thanks, aciddose!

[spacedad]

what simple thing could i do with one AA? maybe you can get bulbs about 0.5? just thinking simple things i could show my kid with a battery and a couple of clips.

also any tips for making your own battery holders?

[aciddose]

main tip i would have is: dont make your own anything.

buying stuff is cheaper and a lot easier. spend 5$ on a cattery holder and it's no problem! making your own.. well i wouldnt really bother it would be far too difficult to get something working decently.

you probably want to get a old 5vdc or 9vdc or 12vdc wallwart supply to fiddle with. just adjust the whole led business for the new voltage: for example 9v supply you'd want a 330 ohm resistor rather than the 47 ohm for the batteries.

(9 - (1.5 Vf)) / 330 = 0.0227A~. (22.7 mA)

that would be the most reliable way to go.. for small batteries you might want to try winding some thin wire around a nail - electro-magnet. you can pick up paper clips or something, that's a good way to demonstrate although not quite as flashy as an led. (literally)

[spacedad]

ok,thanks.more cool tips.
9v connectors are cheaper and smaller.

[intel]

bending _does_ require knowledge of electronics if you want to get anywhere beyond throwing some random components and shorts around, potentially doing nothing at all.

Again?

Didn't you already lose this argument?

***edit***

No, wait. That was someone else. Anyway, that argument has already been lost in this thread. Anything beyond "throwing some random...shorts around" isn't circuit bending.

[whyterabbyt]

Anyway, that argument has already been lost in this thread. Anything beyond "throwing some random...shorts around" isn't circuit bending.

and if anyone still wants to argue intel's point there, maybe they should just read Reed Ghazala's definition, seeing as he's the guy that invented the term (and first documented it for an audience of other instrument builders)

Circuit-bending is an electronic art which implements creative audio short-circuiting. ... Anyone at all can do it; no prior knowledge of electronics is needed. The technique is, without a doubt, the easiest electronic audio design process in existence.

If you learn to solder and can drill a small hole to mount a switch in, you can circuit-bend. Everything else is a process of non-technical, routine experimentation in which various short-circuits are created in an attempt to alter the target device's audio behavior.

Not to say that mods which allow filtering aren't a viable addition to a circuit-bent instrument, but there's a pretty clear distinction between the process which is bending and the process which is modification to the base device.

If anyone's looking to mod their toys but doesnt feel they have the 'lectronic chops to build stuff to add in, btw, then maybe these things might be of interest:

http://thesquarewaveparade.com/parasites.html

[aciddose]

it all depends upon your definition of "bending". let's take the assumed definition to be "useful bending". connecting a short between two ground pins then would not be covered by this definition - it would do absolutely nothing and therefore not be useful.

now that we've correctly defined "circuit bending", we can go on to say that it will require at least a basic knowledge of electronics including the knowledge required to understand the fact that shorting two pins on the same node together will have no effect being that they are already shorted.

i hadn't "lost" any argument, i gave up arguing with someone (see above) who is clearly mentally disabled.

you need legs to run, for example. i'm very sorry to all members of the special olympics, but if you're in a wheelchair you're simply not running. you're wheel-chairing.