# DTMF control



## Liam (Mar 23, 2007)

I'm looking at the D4 DTMF Relay Controller from Animated Prop Systems, and was wondering if any of you have experience with this product or with DTMF in general? It seems like a great option for synchronizing audio and prop effects, and seems pretty straightforward too.

From what I have read, one channel (left or right) will run the actual audio that guests will hear, and one channel will run the DTMF to automate the show. It seems that in Audacity this would be pretty easy to configure.

The board is $80, but that actually seems fairly reasonable. Any other options, suggestions, warnings, etc would be appreciated. Thanks!


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## TheOneAndOnlyKelly (May 7, 2009)

$80 for 4 channels? You can get a 4-channel relay board for a lot less and use a parallel cable and the program Vixen to probably do what you want.


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## Liam (Mar 23, 2007)

So that's a great point, MacabreRob, and brings me to my next question. I already have a ton of EFX-TEK boards (which I do actually use), including regular 120V relays as well as faders. I just have never tried to sync them to audio. My assumption, since everything is digital, is that if I sync up the timing of my prop queues in the program, it should be pretty consistent. Is that assumption correct, or are there other considerations I should be aware of?

I've just never tried actually accurately syncing prop triggers with an audio track, so am not quite sure what to expect.


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## pshort (May 6, 2008)

@rob - unless you want the prop to be standalone, without any PC in the loop.


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## Jaybo (Mar 2, 2009)

I think DTMF control is a brilliant idea for standalone single props or scenes. Someone was talking up DTMF a few months ago. I'll have to search the threads, not sure if it was on this board or another board.

The only other way I know to sync a prop and audio without tethering to a PC, is to use VSA with a RAPU or something similar. That setup will easily cost you $500 or more. So, $80 is a very nice price.


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## HomeyDaClown (Oct 3, 2009)

For about $5 worth of parts (a decoder chip and crystal) plus a arduino ($25) you could have a 16 channel DTMF controller that talks to Vixen and or stands alone and runs your time sequence based on triggers or sensors. 







​
Lots of info here:

http://lucidscience.com/pro-phone number decoder-1.aspx

Only I'd use the arduino code here:

http://code.google.com/p/arduino-based-dtmf-decoder/

Since it decodes all 16 channels on the arduino from the chip. Saves from having to use the 4 to 16 line decoder chip as well.

the $50.00 you save would by a lot of 5 volt relays.


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## DarkLore (Jan 25, 2009)

Liam said:


> So that's a great point, MacabreRob, and brings me to my next question. I already have a ton of EFX-TEK boards (which I do actually use), including regular 120V relays as well as faders. I just have never tried to sync them to audio. My assumption, since everything is digital, is that if I sync up the timing of my prop queues in the program, it should be pretty consistent. Is that assumption correct, or are there other considerations I should be aware of?
> 
> I've just never tried actually accurately syncing prop triggers with an audio track, so am not quite sure what to expect.


I don't want to jack the thread but the EFX-TEK boards have issues with audio sync - due to time slicing. You can use them to blurb out a scream and turn on a light or something, but I had signficant (unresolved) problems trying to do sync like singing pumpkins.

I'm not familar with DTMF.


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## DarkLore (Jan 25, 2009)

HomeyDaClown said:


> For about $5 worth of parts (a decoder chip and crystal) plus a arduino ($25) you could have a 16 channel DTMF controller that talks to Vixen and or stands alone and runs your time sequence based on triggers or sensors.....


Have you done this or are you guessing?

I believe you would encounter the same problems I did with my EFX-TEK boards. Time slicing stored off the computer would not be in sync with the program you created in Vixen. The longer the audio, the more out of sync.

*Addendum* - this solution should work fine for normal effects. I'm referring to syncing to a song like a singing pumpkin effect.


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## pshort (May 6, 2008)

The point of the DTMF decoder is that you have a two-channel audio source (perhaps a PC, perhaps an MP3 player), where one channel has the audio that you hear and the other channel has DTMF tones on it that are used to control or time the physical effects. The DTMF tones are the same ones that you hear when you press the keys on a telephone keypad. Since the audio and the control information are on two channels of a single audio player, they should be in perfect sync. There might be a small delay in decoding the DTMF tones, but this would probably not be noticeable.


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## pshort (May 6, 2008)

@jaybo - no need to search, the link appears at the bottom of this page (although there may be additional threads that don't show up there).

Here is one thread...


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## fritz42_male (May 5, 2009)

For 5 UK pounds you can get one of these and then pipe the binary into a Picaxe. I've got an animated Prop Systems board and plan to build my own as well (I've got one of the ones below). Can't see it happening this year though.

http://www.cstech.co.uk/dtmfdetector.html


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## HomeyDaClown (Oct 3, 2009)

DarkLore said:


> Have you done this or are you guessing?
> 
> I believe you would encounter the same problems I did with my EFX-TEK boards. Time slicing stored off the computer would not be in sync with the program you created in Vixen. The longer the audio, the more out of sync.
> 
> *Addendum* - this solution should work fine for normal effects. I'm referring to syncing to a song like a singing pumpkin effect.


I have done it and It actually works quite well. This is what Gilderfluke has been doing for many years to drive their prop controllers. They use a separate audio channel for just the DTMF tones. That way sync is already there and no need for a computer or Vixen to do the sync. While recording the regular audio on one track, you record the DTMF tones on the other when you want something to trigger. There is already a thread out there for the Asylum Door projects that syncs a Video with DTMF tones to activate either pneumatic valves or on my door, solenoids.
You are only going to get simple on/off control but with 16 channels you can get some interesting effects.


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## Liam (Mar 23, 2007)

Thanks to all of you for your input, this is very helpful indeed.

So, it sounds like for extremely precise triggering, DTMF is the way to go no matter what solution you end up with. But for less precise triggering, the EFX-TEK stuff will probably get the job done. Much appreciated!


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## Dr Morbius (Sep 21, 2004)

Glad to see this idea has taken off! I have also read that people are using the DTMF idea to sync VIDEO with pneumatics and relays on DVD's.

Seems the possiblities are endless.


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