converting line level audio to resistance?

But if it's marked "read", doesn't that mean that you've already read it? Why do you want to read the same post five different times in five different places? Maybe the third or fourth time you read the same old thing over and over again, you'll have thought of an answer?

Then shouldn't the people in the other NGs benefit from your answer too?

Crosspost.

Cheers! Rich

I think we should just ignore googlegroupies as a matter of policy.

Thanks, Rich

Do you have a schematic? In the IBM joystick input, the pots are wired as rheostats and go to +5 on one end and are the timing resistors for one-shots - i.e., their other end just goes to the timing cap - a DC voltage won't work and could damage your game port.

It's not clear at all from that little chart what's really going on inside the atari thing.

And what would it do anyway? Louder goes to the right, softer to the left? ??:-|

Thanks, Rich

"Pooh Bear" schreef in bericht news: snipped-for-privacy@hotmail.com...

resistance

Very good, very good indeed ;)

I was about to suggest a fixed 470K resistor and forget about the audio signal.

I'm not clear whether you want the resistance to be related to the envelope (average volume) of the signal, or to the instantaneous voltage.

Are you trying to make something like an oscilloscope, to display something like a Lissajous pattern (ever-changing squiggly thing that shows phase and frequency relationship between two channels)? Or are you trying to make something that just moves the paddles depending on how loud the sound is?

If the former, you're probably out of luck; I don't think the Atari itself will respond to paddle movement at 20kHz.

If the latter, then Rene's light bulb idea is not a bad one. One problem is that light-dependent resistors (LDRs) with 1MEG dark resistance are usually pretty slow, taking as much as several seconds of darkness to get all the way to 1MEG. The resistance will go low in a hurry, but it takes a long time to recover to high - it's sort of like your eyes when they dark-adapt.

Either way, you probably only need a current or a voltage, not a resistance. That's considerably easier. And I wouldn't worry about getting the (effective) resistance any lower than 1k ohms, since the pots in the joystick are almost certainly linear (as opposed to log-taper): the difference between 1k and 0 is 0.1% which is less than the pots themselves can distinguish.

Give Rene's idea a try, as a start. If it doesn't work you can evolve it.

out

Maybe it's this damn google groups interface, you click Reply and assume it is quoting the original article and then it doesn't

for it.

That sounds easy, I will need to multimeter it.

1) blowing up the stereo if the output resistance is not 8 ohms (or whatever the output expects for headphones) - that's why I originally said Line Level, this would be a single standard as opposed to different stereos which need different resistance speakers.

video game (Atari 2600 paddle controls

with my stereo.

you while you get

The way your pots are connected suggests that your game is already voltage driven, so you would only have to amplify your audio to cover the 0-5V range. For starters try connecting your audio output directly to the paddle pin (and gnd to gnd) and see what happens.

Foo,D

something

phase and

make

sound is?

itself

The latter would be easier and would probably do the job, but the oscilloscope version would probably be more interesting. If the circuit could take the frequency (say 0 Hz - 20,000 Hz) and find the equivalent fraction within the Atari's range (1k ohm thru 1 MOhm), then it would be able to convert it to paddle movement the Atari will recognize.

envelope

something

phase and

make

sound is?

itself

problem is

usually

all the

long

dark-adapt.

resistance.

themselves

evolve it.

I read in sci.electronics.design that Mad Scientist Jr wrote (in ) about 'converting line level audio to resistance?', on Tue, 20 Sep 2005:

originally

You are trying to do something beyond your present understanding, so you need to learn. You do that by reading the advice you are given carefully.

You will not blow up the stereo if you feed its output into anything LARGER than 8 ohms. It doesn't need 8 ohms across the output (unless you have some weird audiophool amplifier). The loudspeaker or headphone output will give you 5 V of audio, but the line level output will not;

you might get a maximum of 2 V but probably less.

However, you should include a diode (1N4148, anode to the stereo) in series between the stereo hot output and the **slider** connection of the paddle, which must be disconnected from the actual slider. The input might well not like -5V at all. You do not connect anything to the +5 V at the 'top' end of the paddle resistance, so it doesn't come into the

scene at all. The 'cold' output from the stereo goes to the ground end

of the paddle resistance.

of

as

See above. The 5 V is no longer connected to the connection that went to the slider.

This is not only impossible in the way you want it, it isn't the right

way to do it.

That doesn't make any sort of sense. Don't just throw out technical words, try to learn. If you don't want to learn, please go away.

originally

of

as

doesn't

you get

If you are going to connect the line level voltage to replace the paddle , then you will not use the 5V connection. The voltage reference will be the audio ground. Just in case it hasn't been mentioned, it would be a good idea to put a diode in the circuit path to assure that only a positive voltage is applied. You can protect the input further, by putting a

Don

That's an interesting idea - how would you get the circuit to max out

MOhm and at a minimum, go to as close to 0 ohms as possible?

leave enough of the post you're replying to in your post to

you're responding to then we won't have to digging

I think we should just ignore googlegroupies as a matter of policy.

Thanks, Rich

But if it's marked "read", doesn't that mean that you've already read it? Why do you want to read the same post five different times in five different places? Maybe the third or fourth time you read the same old thing over and over again, you'll have thought of an answer?

Then shouldn't the people in the other NGs benefit from your answer too?

Crosspost.

Cheers! Rich

to control a video game (Atari 2600 paddle controls

to 5V DC) with my stereo.

playing for you while you get

connected suggests that your game is already voltage

have to amplify your audio to cover the

connecting your audio output directly to the paddle

see what happens.

pots are wired as rheostats and go to +5 on one end and are the timing resistors for one-shots - i.e., their other end just goes to the timing cap - a DC voltage won't work and could damage your game port.

It's not clear at all from that little chart what's really going on inside the atari thing.

And what would it do anyway? Louder goes to the right, softer to the left? ??:-|

Thanks, Rich

try to learn.

Fair enough, I have to digest all this and I have some reading to do.

Thanks to you and everyone for your replies.

1. John Woodgate Sep

John Woodgate - Find messages by this author

Date: Tue, 20 Sep 2005 17:00:07 +0100

Subject: Re: converting line level audio to resistance?

Author | Forward | Print | Individual Message | Show original | Report Abuse

usenet snipped-for-privacy@yahoo.com wrote (in

snipped-for-privacy@g14g2000cwa.googlegroups.com>) about

level audio to resistance?', on Tue, 20 Sep 2005:

stereo if the output resistance is not 8 ohms (or

for headphones) - that's why I originally

single standard as opposed to

resistance speakers.

understanding, so you

given

into anything

(unless you

headphone

not;

should include a diode (1N4148, anode to the stereo) in

stereo hot output and the **slider** connection of

disconnected from the actual slider. The input

You do not connect anything to the

resistance, so it doesn't come into the

the stereo goes to the ground end

blowing up the video game - it sends 5v out and measures how much of

comes back. I assume the signal from the stereo sends voltage as

happens when you have the 5V from the game, plus the

went to

sending out?

resistance

the right

doesn't blow up

out technical

designed, a god designed evolution by natural selection.

Now that's a cool idea. Let your stereo do the playing for you while you get on with your life...

The way your pots are connected suggests that your game is already voltage driven, so you would only have to amplify your audio to cover the 0-5V range. For starters try connecting your audio output directly to the paddle pin (and gnd to gnd) and see what happens.

Foo,D

The pot is the timing resistor in an ordinary one-shot, at least in the PC game port. It needs the +5V supply to source the current from that it charges the capacitor with.

Hmmm - I was just looking up the schematic for the PC game port, and stumbled across this:

So OP is looking for a couple of relays and an ADC of some kind - what the heck is this guy expecting to accomplish?

Thanks, Rich

"Pooh Bear" schreef in bericht news: snipped-for-privacy@hotmail.com...

Very good, very good indeed ;)

I was about to suggest a fixed 470K resistor and forget about the audio signal.

I read in sci.electronics.design that Mad Scientist Jr wrote (in ) about 'converting line level audio to resistance?', on Tue, 20 Sep 2005:

You are trying to do something beyond your present understanding, so you need to learn. You do that by reading the advice you are given carefully.

You will not blow up the stereo if you feed its output into anything LARGER than 8 ohms. It doesn't need 8 ohms across the output (unless you have some weird audiophool amplifier). The loudspeaker or headphone output will give you 5 V of audio, but the line level output will not; you might get a maximum of 2 V but probably less.

However, you should include a diode (1N4148, anode to the stereo) in series between the stereo hot output and the **slider** connection of the paddle, which must be disconnected from the actual slider. The input might well not like -5V at all. You do not connect anything to the +5 V at the 'top' end of the paddle resistance, so it doesn't come into the scene at all. The 'cold' output from the stereo goes to the ground end of the paddle resistance.

See above. The 5 V is no longer connected to the connection that went to the slider.

This is not only impossible in the way you want it, it isn't the right way to do it.

That doesn't make any sort of sense. Don't just throw out technical words, try to learn. If you don't want to learn, please go away.