Microphone into 0-10 Volt Analog

We would like to pick up a sound through a microphone into an analog module. The available analog is 0-10 volt and the ideal is to use it.
Does anyone know of an easy way to do this? It works somewhat as we can see a fast spike in the 0-10 signal however it is not maintained long enough to be 100% reliable.
Thanks for your input.

You realize that sound is in the range from 20hz to 20Khz, not to mention harmonics involved. I am not sure the average plc can handle the frequencies involved. Could you be more specific in what you are trying to do?

I'm with RSDORAN give us a better clue as to what you'r up to. You may find that you really want a digital input if you are looking for an event. No end of circuts around to manage that.

Lenny

Detecting sound

We are attempting to detect a solid state alarm. We are testing to verify that the alarm actually does work. The PLC activates the alarm for a given period of time and we need to determin that the alarm sounded. A discrete input would work? What do you recommend? The alarm is about 15 kHz at 70 db.

Thanks for your help.

My first thought would be to use an ADC (analog to digital converter) to convert the sound to a digital signal.

You may be able to use that analog input but I aint picturing that in my head yet. You may want to look at using a crossover and taking inputs from bass, treble, & mid-range which may allow more precision

Another thing would be to use a sound activated relay, many available in the market or you could build your own.

The sound activate relay is the way I was thinking. I used a "Sensitive Voice-Activated Tape Recorder Switch" for much the same sort of application. I got it as a kit in the local electronics parts house. One of the build it yourself hobby kits for about 5 bucks US. It drives a realy and then that goes to a DI on my PLC.

Lenny

Lenny has a good idea. But, the problem is that the switch will respond to ALL local noise. Someone farting next to the microphone will turn on the output - I don't think that's what you really want.

It was said that sound is 20Hz to 20kHz...
Actually, that is simply, and generally, OUR (human) range of hearing.

"Sound" is a relative term... Tree in the forest thing... remember?
Sound-Energy is still Sound-Energy, whether we can hear it or not.

There are plenty of critters that can hear things that we can not.

Lower: Elephants, Whales,...
Higher: Dogs, Bats,...

Of course, at some point, it becomes ridiculous to speak of that energy as "sound".

Anyway, you are looking for a particular frequency (15kHz +/- ?%) at a particular power level (70-db). It is most likely that 15 kHz sound will exist in almost any industrial environment. The critical factor is the power level of that sound. If the power level (db) is low, then you're not likely to hear it unless you stand next to it. If it is high enough, you might not be able to hide from it - hence, ear-plugs, head-sets, etc.

As I recall, 70 db is pretty damned high!

Here's my suggestion...

1. Design a Band-Pass Filter to pass 14-to-16 kHz. (15kHz +/- 1kHz)
   (search the net, there are many on-line filter designers)
   
2. Add an attenuator on the input to the Band-Pass Filter.
   
3. Pass the output of the Band-Pass Filter to the switch suggested by lenny.
   -- You could connect that signal directly to the input circuit on the lenny-switch detector (bypassing its microphone) ...
   --OR--
   -- You could use the signal to drive one of those small crystal-speakers mounted next to the microphone on the lenny-switch. You will need to enclose the speaker and microphone in a sound-proof box.
   --OR--
   -- Convert output to DC and drive an amplifier which closes a relay.
   --OR-- ??? There are all kinds of games you can play!
   
4. Set the lower threshold (activation level) on the lenny-switch.
   [/list=1]
   
   The relay, driven by the lenny-switch then provides your digital input.
   Input ON = Signal (15kHz), of sufficient power (70db), is present.
   
   The microphone (audio pick-up) should be place near the source.
   You might need to install some sort of muffler on the microphone to keep it from Physically over-driving.
   The attenuator will keep it from Electrically over-driving.
   
   Because of the power level of the source, you should do some checking to find the best type of pick-up. A regular microphone, like we use for recording speech, might not be the best choice.

Terry is on the money here.

The circut I used had a fair attenuator built in but we had to "tune" on it to get where we wanted to go. The levels we were working with are in the same range 55-80 DB but our transducer was not a voice mic. The same folks that produced our little kit also produce an active audio filter kit that could be used if you are not an electronics design type. We just modified the kit amplifier circut to filter out noise. Our frequency of intrest was also not as narrow as yours.

We modifed the threshold detector in the kit to act more as an envelope detector, fed that to the on-board solid state switch driving a relay. As I recall the testing, it had around a 2kc bandpass and we could move the centre form about 9-20kc. The trip point would be varible from around 40 to 90 DB though that was not as critical a parameter as freq. in our application.

Good luck. Hope we haven't hit you with information overload here.

Lenny

Why use a mic? I would hook the output of the transducer to a comparator then to a DI.

VJTX said:

Why use a mic? I would hook the output of the transducer to a comparator then to a DI.

Click to expand...

VJTX,

Alert:
This thread was started 8 years ago.

Mickey said:

VJTX,

Alert:
This thread was started 8 years ago.

Click to expand...

LOL, this happens to me all the time here. What a great site!

Paul B said:

LOL, this happens to me all the time here. What a great site!

Click to expand...

yeah, gave me a good laugh!! Gotta love it.

Hopefully he's solved the problem or retired by now.