Thread: audio questions

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looking for somthing to use for audio
i have used the cowalicious chips
before but they seem to get interference
and trigger randomly
i would like to use somthing in the same setup
thoe
any ideas

are you using a trigger device that's connected to the board via a cable?

does the cable run with 12" of any AC cables?

I used to have similar problems, with false triggering. I used to run the trigger wires all the way back to the control rack, using CAT5 cable, but could not stop the false triggers. I usually happened when I would trigger some other device, like a light or motor.

What I do now is use a relay located close to the Cowalicious board to close the trigger contacts, then use 24v from the controller to close the relay when needed.

Since switching to this method I have not had any false triggers.

Originally Posted by SpookyKingdom

I used to have similar problems, with false triggering. I used to run the trigger wires all the way back to the control rack, using CAT5 cable, but could not stop the false triggers. I usually happened when I would trigger some other device, like a light or motor.

..... I bet you ran the signal cable along side or crossing over the power cables.

CAT5 should help provided you used a twisted pair for the signal cable.

I have used the Daisy MP3 player board for several props and it works very well and is easy to use. You can get it from the Make Magazine store (just google Daisy MP3 player and you will find it). It is expensive at more than $100 and you have to assemble it yourself but it produces CD quality sound from your files stored on a SD card. It operates in several different modes and several of the modes require only a low going pulse to trigger it. However, if you are having false triggers on the other board you are using you may have the same problem here so I suggest you try and find out what is causing that issue before you invest $$ in another solution. You might also try putting something like a .1uF cap from your trigger pin to gnd to try and filter out some of the noise you are getting on the trigger pin.

Cat 5 only helps if you have a differental signal, it actually makes things worse if you are not running a differental signal. the cables are twisted and one pair can induce voltage in another pair.

If you are just running a contact closure you should not use twisted pair (Cat5) cables.

See this for an explination of a differental signal:

Differential signaling - Wikipedia, the free encyclopedia

Here in the states with our lower voltage 110VAC vs. 220VAC that is prevelent in Europe false triggering from running your signal cables with your power is rare, but can still happen on occasion.

I belive I saw a thread on the cowalicious false triggers somewhere where the fix was adding a capacitor to the input or something, but I can't find it now.

Sorry, got to dissagree with the point about 110VAC being less noisy than 240VAC, probably the worst candidate I've ever seen for noise was a low voltage 35-100VAC dimmable lighting system that I bought from a local hardware store (here in the UK) and it threw up so much noise that I nearly pulled the plug on the whole system before I finally found it!

Since my experience with that particular system I now always run power cables down the opposite side of corridors than signal cables and make a point of ensuring that a signal cable never comes within 12" of a power cable.

if your device is power factor corrected there should not be any noise on the 110V Line.

Power-factor correction - Wikipedia, the free encyclopedia

Power Factor Correction is fairly new (within the last 10 years), most equipment sold today is power factor corrected and will not cause noise. but if you buy some equipment from billy bobs electrical supply house that was cobbled together it probally is not.

in pro audio we use the same 12in and 90deg cross rule for any signal cable: mic,line,dmx,etc in the studio and on stage. I can't tell you how many times i have heard someone complaining that they are getting a buzz in a recording and i find they have their mic cables running with power cables.

proper cable shielding is also a must, you could pick up some RF interference on long runs.

also what source are you using to trigger this, some devices can send out small pulses or just be bad devices, like a bad mat switch that will touch occasionally

95% of the audio buzz these days is related to shielding ground loops - I am a professional AV engineer and in the old days, yes the buzz was usally related to running audio lines with the power lines. today with the power factor corrected devices and the electronic balancing of the audio signals this is rarely the case. Mostly the buzz comes from shielding not done correctly (the shield should be droped at the microphone).