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Circuit Bending Nintendo (NES) - Use transistors as switches?

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jordan_ellipsis

New Member
Hello lovely people of the forum!

I'm currently circuit bending an original Nintendo Entertainment System (the one from the 80's). For those unfamiliar with circuit bending, it's basically when you expose the circuit of a device and create short circuits in arbitrary places in the hope of corrupting it's functionality. Commonly performed on cheap, battery-powered kids audio toys. It requires no experience in electronics to start 'hacking' at an elementary level, which, unfortunately, is the category i fall into You flip the circuit board over so all you see are the solder blobs, and use crocodile clips (or jumper wire) to connect various 'blobs' together, therefore forcing a change in the circuitry, and often resulting in crazy outputs! Kids toys can end up screaming with distorted, alien voices... it's very fun.

So i've been applying this methodology to the NES. When i connect certain points together, the image glitches, see an example here: **broken link removed** The standard practice would be to connect two 'bend points' together using a physical SPST switch, so the glitch can be turned on and off.

But I'd like to control these switches from a Max/MSP patch, using an arduino board. My problem is not with using this board, hence why i have not posted this in the arduino section. Feel free to move it there if you think it is better suited. The arduino board has it's own 5V power and ground. It has digital output pins which can send logical HIGH signals. I plan to use one of these output pins to control my switch.

I've been researching this like mad, and was initially advised down the route of using a relay switch. But the more I read, the more it seems like a transistor is the tool I need! I would use a digital pin from the arduino (in output mode) to send +5V to the transistor, therefore closing the switch and activating the glitch. Does this sound like the right idea?

I know this is probably an extremely basic circuit, but could someone help me with the schematic? And also the correct transistor to use, along with any other necessary components?

Just some extra info here, the power supply for the nintendo reads:

INPUT AC230/240V 50Hz 17W
OUTPUT AC9V 1.3A

Can this information be used to calculate the value of the transistor needed?

From my knowledge so far, i'd want to connect the digital pin output from the arduino to the Base of the transistor with a 1k resistor in between. This would 'control' the switch.

I'd connect the collector to one of the bend points (point A), and i'd connect the emitter to the other bend point (point B). So when the switch is closed, current runs from bend point A to bend point B thus activating the glitch.

Is this sounding right so far?

I then am little confused as to where to connect the power and ground of the arduino. Do i connect the ground to the emitter, and also to the ground of the NES? And then connect the power to the collector, and also to the 9V from the NES?

Please please help if you can!

I realise it's frustrating dealing with someone with limited electronic knowledge, but I'm willing to listen to/read/learn whatever is required to make this happen! It's probably so simple, but I really couldn't find anything online about using arduino boards to activate bend points on circuit bent instruments.

Thanks,

Jordan
 

MikeMl

Well-Known Member
Most Helpful Member
Ok, what happens when you short two nodes together that happen to have 230Vac (line voltage) between them??? You will modify how the circuit works, all right...
 

jordan_ellipsis

New Member
Yes it is modified. The image on the screen is distorted, like in the picture shown. It basically looks like what happens when you don't properly insert a NES cartridge.

So the current of the NES circuit (1.3A?) will be running through the transistor I use. I'll need to make sure I use a value of transistor that can cope with this.

I will buy a few transistors tomorrow so i can get testing this finally.

I've used this schematic (the left one) as a rough guide. I just need help calculating the resistor values i need to use. And also where to connect the ground and power from the arduino and NES?
 

Dr_Doggy

Well-Known Member
what they said , you are only considering that it is all at 5v which may not be the case, if you really need to do this id suggest a more isolated resource like a relay, lots of schematics out for that. so when sparks fly the chip is safe

i need to ask though, why?

what you are witnessing is a byte of data that got lost along the bus
 

jordan_ellipsis

New Member
Within that lost byte of data lies the beauty of circuit bending!

When the two 'bend points' are connected, it causes a glitch in the game's image. Something like **broken link removed** When the points are separated it goes back to normal. I'm outputting the nintendo video feed through a projector as a visual backdrop for a performance of electronic music. The music is made using circuit-bent instruments; usually 5 buck kids toys which have been re-wired to sound crazy. Read more on circuit bending here if you're interested; it's a very exciting area.

If I can control the glitch from the microcontroller (arduino) i can control how the glitch is triggered (i.e. what makes it turn on). Working in Max/MSP, i can program the switch to turn on when the audio feed does certain things. So, e.g. when a high-pitched sound is made, the switch might close. Or, more effectively, when a sound over a certain volume threshold is produced, the switch will close. When the sound drops back below the threshold, the switch opens. So the visual backdrop will appear to operate in sync with the music.

I've got all the programming side of things ready to go. All i need to do is build a small circuit so when my arduino outputs a logic HIGH, the transistor closes, allowing the 'glitch' to occur.

The Nintendo is 9V 1.3A. Do you think the voltage or current will be too strong for a transistor to cope with? If this is possible with just a transistor i'd like to do it that way. If you think it must be a relay, then I shall go down that route. Could you possibly explain why I'd need a relay? This is where my lack of knowledge really bugs me; i get confused between how voltage and current are going to impact circuits.
 

4pyros

Well-Known Member
Most Helpful Member
Ok, what happens when you short two nodes together that happen to have 230Vac (line voltage) between them??? You will modify how the circuit works, all right...
Nothing! It runs off a wall wart. At lease benders dont mess with mains voltage, mostly its battery powered stuff.
Another term for it is breaking stuff.
In a fun way, but more like repurposing it keeps the junk out of the land fills!
i need to ask though, why?
Because its fun making stuff do other things than it was made to do. Like using diodes for distortion or making BEAM bots out of inverters.
 

4pyros

Well-Known Member
Most Helpful Member
I've been researching this like mad, and was initially advised down the route of using a relay switch.
Stick with relays you can't go wroung. With transistors you would have to deal with polaritys, resistances, and voltages. Can you get a relay sheild for your arduino?
Andy
 

DerStrom8

Super Moderator
I agree with Andy. In order to use transistors, you would somehow have to link the circuits of the NES system and the arduino together, which would be considerably difficult if you plan to simply connect a transistor between two points. It would be easier if you knew that, for example, the emitters of all NPN transistors were connected directly to ground, because it might then be possible to simply link the grounds of the circuits. This is obviously not the only thing that would need to be true, but it is just one example. In your case, though, since this is likely not the case anyway, it would be significantly easier to use relays. Relays are better used to replace a mechanical switch, as they, too, are mechanical. Transistors, on the other hand, are electrical switches and require various conditions to be true in order to be used.
Der Strom

P.S. Welcome to ETO :D
 
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jordan_ellipsis

New Member
Thanks for the welcome :) I feel I'll be using this forum A LOT from now on!

Thanks for the responses too.

Just one last note on the transistor: when you say i'd have to link the circuits of the arduino and NES together, do you mean connecting their grounds together, and their powers together? That's what I thought i'd have to do, and was going to do this on a breadboard (where the transistor would also be, obviously)

There is a schematic on the arduino website for using relays; it looks like this.

I wonder if someone could talk me through it a little bit, with a view to constructing it on a breadboard? Mainly how to identify the 4 different legs (pins?) of the relay, and what they should be connected to.
Would I be able to use a small 5V relay? Because I could then power the relay from the arduino's 5V supply.
In the bottom right corner, where it says RELAY power GND, does this mean connect one leg of the relay to the NES's ground?
I'm assuming I just want a simple SPTP relay yeah?

Thanks, and really sorry if this is frustrating for you guys..

Jordan
 

jordan_ellipsis

New Member
Hmmmmmm, but that post just worked :-S

DerStorm: would linking the circuits not just mean linking the grounds? Link the ground of the arduino and the NES, and make both also connected to the transistor?

There are schematics on how to use relays with transistors, but i cannot link to them because this post will be delayed so moderators can check it. Yesterday I bought a 5Vdc 2A relay and also a 12Vdc 5A relay, both SPDT. The arduino can supply a +5V; does this mean i could use the 5V relay? Or should i use the 12V relay and power it from the NES? What values of transistor and diode should be used?

A little bit of guidance assembling all the correct points together for this circuit would be most appreciated, if you could!? I'm very grateful for the help so far. I'm determined to get my head around this stuff because there are further projects i'd like to attempt in this field i.e. combining circuit bending w/ micro controllers!
 

4pyros

Well-Known Member
Most Helpful Member
Jordan; Are you going to put the arduino in the NES or keep it out of the case? I think the best bet would to make the relays like a sheld and then wire the relay contacts the the bending points on the NES just like it was a switch. Do not link the grounds together that could cause bad things to happen. So power the relays on the arduino side and bring out the relay contacts to you projects. That whay you can use the arduino and the relay sheild on anything. Andy
 

DerStrom8

Super Moderator
Hmmmmmm, but that post just worked :-S

DerStorm: would linking the circuits not just mean linking the grounds? Link the ground of the arduino and the NES, and make both also connected to the transistor?

There are schematics on how to use relays with transistors, but i cannot link to them because this post will be delayed so moderators can check it. Yesterday I bought a 5Vdc 2A relay and also a 12Vdc 5A relay, both SPDT. The arduino can supply a +5V; does this mean i could use the 5V relay? Or should i use the 12V relay and power it from the NES? What values of transistor and diode should be used?

A little bit of guidance assembling all the correct points together for this circuit would be most appreciated, if you could!? I'm very grateful for the help so far. I'm determined to get my head around this stuff because there are further projects i'd like to attempt in this field i.e. combining circuit bending w/ micro controllers!

When I mentioned linking the circuit grounds, I said that that is really only possible for very simple circuits. In your case, it would be a very bad idea because of the different power supplies and the more complex circuitry. There are hundreds of things that could go wrong.

Your relay should have two different voltage ratings--one for the coil and another for how much it can switch. We'll need to know which is which before you can continue. If 5 volts was the coil rating, it should work with your arduino. If it is the contact rating, you will need a different one that can switch the power of your NES. If you can give us this extra information, we will be able to help you further.
Der Strom
 

irbirb

Member
okay, but just one thing.. you want to use a computer to control a bent NES?
is it a very special max/msp patch or might there be a much simpler route?

i'm going to agree that relays might just work better for you than transistors, but i'm sure you've noticed the price difference. you might consider opto-isolators or perhaps just some 4066 chips. the 4066 bi-directional switches have been shown as quite effective for doing what you're trying to do.
 

jordan_ellipsis

New Member
Andy: i hadn't thought whether i'd put the arduino in the NES or not. I'll look into that shield idea ;-)

Der Storm: The 5V relay has this info on it:

1A 120VAC
2A 24VDC

The 12V relay has this info:

COIL 12VDC
5A 240VAC 50/60Hz
5A 28VDC
-----------------------------

Am i right in saying the 5V relay will be able to be powered from the arduino (as the coil is 5V, same as arduino output) and because it can handle up to 24Vdc? My NES will be 9V or 12V i imagine?


Irbirb: Yes the Max patch is special. It analyses incoming audio from the instruments we are using during the performance. It can determine pitch, brightness, volume, frequency-range etc. I can use these varying values to trigger outputs from the arduino e.g. a very low frequency sound may trigger a certain pin to output a HIGH logic value. I can use this output to switch a relay and thus connect the two 'bend points' in the NES circuit, causing the image to glitch. There are many other examples of how i will use this. The effect will be that the visual graphics appear to change/distort in sync with the audio.

I've had a few people suggest things like 4066 chips, or 4053 chips... these do seem fairly straight forward - what might be the benefit of a 4066 over a relay circuit?

Again, thanks a million guys :)
 

DerStrom8

Super Moderator
Der Storm: The 5V relay has this info on it:

1A 120VAC
2A 24VDC

The 12V relay has this info:

COIL 12VDC
5A 240VAC 50/60Hz
5A 28VDC
-----------------------------

Am i right in saying the 5V relay will be able to be powered from the arduino (as the coil is 5V, same as arduino output) and because it can handle up to 24Vdc? My NES will be 9V or 12V i imagine?

Yes, that should work. Just make sure there will not be more than 2A across the relay contacts.
Der Strom
 

irbirb

Member
I've had a few people suggest things like 4066 chips, or 4053 chips... these do seem fairly straight forward - what might be the benefit of a 4066 over a relay circuit?

cost, speed, reliability, durability, and the sound pollution from relays as they go 'click click click' all the time.

Irbirb: Yes the Max patch is special. It analyses incoming audio from the instruments we are using during the performance. It can determine pitch, brightness, volume, frequency-range etc. I can use these varying values to trigger outputs from the arduino e.g. a very low frequency sound may trigger a certain pin to output a HIGH logic value. I can use this output to switch a relay and thus connect the two 'bend points' in the NES circuit, causing the image to glitch. There are many other examples of how i will use this. The effect will be that the visual graphics appear to change/distort in sync with the audio.

yes, i'm sure i know what you are going for... i just meant that max/msp is bringing an extraordinary level of sophistication to something which might be accomplished without needing to use a computer. just saying.
 
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4pyros

Well-Known Member
Most Helpful Member
Just a note; Transisters will always have an on resistance. The 4066 is about 80 ohms when on. With this resistance your bends my not behave the same as if it was switched with a switch or a relay that has 0 ohms resistance. To use transisters you may have to test for your bend points using a resister and it may limit your posiblitys. Some bends just may not work with 80 ohms. Andy
 
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DerStrom8

Super Moderator
How many bends to you plan to have on the single NES at one time?
 
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