Thread: Audio activated switch/lightning machine…CHEAP!

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Ummmmm....IIIII..LIKE IT!

Think there's some mods in store for my lightning machine.

Thanks.

Bob that was a great post.
It was sorta what I was looking for but I wanted to see if you might be able to come up with a solution for me on this one.

I have an audio track with voice and music mixed. tried to un mix it but it just truned to mush.

So throughout the track there are audio sections I would like up to four skeleton heads to individually chime in at those spots. Each having a different spot to have their mouth move to. Like each one singing a verse. Problem is there are four heads I need to have and only two channels of audio to work with.

If you might have a solution I would greatly appreciate any input you might have.

thanks a bunch.

GH

Originally Posted by Garagehaunt

BI would like up to four skeleton heads to individually chime in at those spots. Each having a different spot to have their mouth move to. Like each one singing a verse. Problem is there are four heads I need to have and only two channels of audio to work with.

If you might have a solution I would greatly appreciate any input you might have.

You can do it with just one track... using frequency and filters.

One skull's input filtered to move with 100hz, one at 500hz, one at 1000hz and another at 2000hz. Those are all easily reproducible at any bit depth or sample rate!

Hack on...

Push E.

Ok I understand the frequency blips in the same audio track, but how would I have the skulls (who normally use audio to move th mouth) use frequency to move the mouths.

Whats the product to by. and then does this mean I would need to puppeteer with the frequencies for the skulls. Thats a job all in its own if thats the case.
So whats to be done on over lapping frequencies, here one sentence is trailing off the other is starting?

all the help is greatly appreciated.

This circuit isn't really designed to control jaw movement on a skull, but I understand the frequency and filters bit. I would use that idea for simple on/off switching. Sounds like you need servos and servo controllers here.

If all you need is to turn on or off a motor or a switch, and you want to control muliple on/off cycles from one audio file, you can easily do that with tone switching. Here's how I would set it up. One channel of the stereo audio would contain the straight audio that eveyone would hear.

The other channel would contain the different tones. The VU meter switches I talk about in this post would all have their inputs hooked to the output of the 'Tone" channel, but that output would go into a filter first.

Something similar to a low-pass filter that blocks everything except bass frequencies would be used, except you would want more precise control over what frequency range would be allowed through. There are circuits and schematics available online for this sort of thing. It is how electronic crossovers in stereo equipment work.

Here is my example:

you have 4 switches you want to control at different points within an audio file.

Use 4 different tones created by a tone generator. All at different frequencies. One could be 100 hz another could be 500 hz, a third 1000hz and 1500hz could be the fourth.

You would need 4 filters. Their job would be to block everything except the frequency range they are set up for.

In this example, one filter would be designed to block every frequency above 150hz. This would allow the 100 hz frequency through, but block all others. The output of your "Tone" channel would feed into that filter, and the output of that filter would feed into the audio switch you made from the VU meter. The only thing that would activate that particular switch would be frequecies below 150 hz. Therefore, if a different tone were to overlap, let's say that they 500 hz frequency also hits while the 100 hz frequency is playing....Only the 100 hz frequency would get through the filter to this particular switch and it would not "hear" any other frequencies, therefore would not react to them.

The 500 hz tone would be there, but would be blocked by that switch.

Also hooked up to the output of the "Tones" channel would be three other filters. One of them would be set to block all frequencies except those within the 400 to 600 hz range.

This second filter would feed the input of a second audio switch made from the VU meter.

That second switch would only "hear" the 500 hz tone because all other frequencies would be blocked. It would only turn on for the 500 frequency whether any other frequencies were present or not.

You would do the same for the other two filters. Each of them set to block everything except the one frequency that you want to allow through.

This would give you the on/off control for as many switches as you want, all fed from the same audio channel with as much overlap as you want.

You could even take it a step further and mix the tones right into the existing audio track. Just choose frequencies that are above or below the ability of the human ear to hear. If the filters are set up to allow those frequencies through, they should still register on the VU meter and control your switch. You might drive some neighborhood dogs crazy in the process, but it should work.

Ok that all makes sense, The skeletons I have already have an input line that accepts audio for its mouth movement. I think the on/off will work just fine for this round of usage.

[{"The VU meter switches I talk about in this post would all have their inputs hooked to the output of the 'Tone" channel,"}]
~I didn't see a line-in or a lineout on that VU meter???
is the line out the LED's?? Just checking
Sorry if the questions seem stupid, but this will be my first time.

So what or where do I pick up an audio filter that I know will filter out the right tone to the VU meter switch?
Are they cheap?

Also with two channels (left/verbiage- right/tones) do I just Y (4 lines) divide the right channel to each of the four skeleton heads?

So I am correct in my assumption, let me text out your design and see where I need corrections or not.

Four Skellys talking:
1) MP3 Player with stereo track (left/verbiage- right/tones)
2) left channel is output to the amp
3) Right Channel is y'd out to the four skeleton heads

~Each head has the following setup:
a) Tone line output to Filter
b) Filter output to VU meter switch
c) VU meter switch output to Skelly head (for on off action)

Also I was wondering if i use a Stereo VU would I optimize my circuit usage? (by two instead of four)

thanks so much for all of your help.
GH

PS
would you have a picture of the filters i would need to get?

I will attempt to answer all your questions by addressing them as you posted them:

[{"The VU meter switches I talk about in this post would all have their inputs hooked to the output of the 'Tone" channel,"}]
~I didn't see a line-in or a lineout on that VU meter???
is the line out the LED's?? Just checking


Yes, the output IS the LEDs. I no longer think that you need to use the VU meter at all. I was telling you that the VU meter will work to turn things ON or OFF. It will NOT give you an audio output that will drive your skeletons the way you want. For you, the process I outlined above will still work, but you will not need the VU meter switches, so you save money.

You tell me that your skeletons accept an audio input which controls when the mouth opens or closes. I didn't know that before. So now all you have to do is to send a different audio signal to each skeleton (by the use of filters) and it should work. You can adjust how long the mouth stays open by adjusting the length of each tone that you send.




Sorry if the questions seem stupid, but this will be my first time.


There are no stupid questions........ok, well very few. This isn't one.



So what or where do I pick up an audio filter that I know will filter out the right tone to the VU meter switch?


You don't pick them up....you make them, and as stated above, you won't need the VU switches.


Are they cheap?

Yes. Just a few electronic components that you have to put together.





Also with two channels (left/verbiage- right/tones) do I just Y (4 lines) divide the right channel to each of the four skeleton heads?


Yes, that is how you would do it. You just need to be sure that after splitting the signal 4 ways, you still have enough signal strength (Volume) to trigger the skeletons. If not, they sell pre-amp kits that you can build to boost the signal. (here is one. http://www.hobbytron.com/vk2572.html It is stereo, so you only need to use one channel. I know they sell mono ones that are cheaper. You would boost the output before splitting it and sending it to the filters)


So I am correct in my assumption, let me text out your design and see where I need corrections or not.

Four Skellys talking:
1) MP3 Player with stereo track (left/verbiage- right/tones)

Correct

2) left channel is output to the amp

Correct


3) Right Channel is y'd out to the four skeleton heads

Correct

~Each head has the following setup:
a) Tone line output to Filter

Correct


b) Filter output to VU meter switch

Again, skip the VU meter switch and go directly to the skelly's from the filter output.


c) VU meter switch output to Skelly head (for on off action)

Also I was wondering if i use a Stereo VU would I optimize my circuit usage? (by two instead of four)

It would if you needed them.



And now.... Let's get back to the filters. Here is a good webpage that explains what a band pass filter does. http://www.allaboutcircuits.com/vol_2/chpt_8/4.html

yopu would need 4 of these circuits. They would all be the same except for some of the component values. It is a combination of a low-pass filter and a high-pass filter. The high pass filter passes (or allows through all frequecies ABOVE a predetermined level. Then the low pass filter passes all frequencies BELOW a predetermined level.

So if the high pass filter is set to block everything below 400hz, then only those frequencies ABOVE 400 Hz would get through. That output is then sent to the Low Pass filter. We would set the low pass filter to block everything above 600 Hz which means that it would allow everything which is at 600 Hz or LOWER to get through.

Since it was not fed anything below 400 Hz, the only thing that would get through would be frequencies between 400 and 600 Hz. This would be a good filter to use for your 500 Hz singnal Pulse. That would operate one of the skeletons. Even if 3 other frequencies were present at the same time, they would have all been blocked by this filter and only the 500 Hz frequency would get through.

I will look for more schematics for building the band pass filters and post some when I find them.

Go to this site and about halfway down, under Calculating Frequencies, download the program they offer. http://sound.westhost.com/project63.htm

In the Calculate R column, enter the frequency you want to allow through, then enter 1 for Gain, and 10 for Q. That will provide you with the values for the components in the schematic.

Repeat this using all four of your desired frequencies, then run off to Radio Shack to buy parts.

Another good page which explains this is here:

http://www.mathworks.com/academia/st..._problem1.html

Bob,
Thanks for all of the info.

It would be great if these things could just be bought with a potentiometer.

I am sure sooner or later someone will catch on to the need and mass produce them.

I'll be looking for more posts if you find them about the schematics.