Home     Contact     Forum     Projects     Experiments     Circuits     Theory     BLOG     PIC Tutorials     Time for Science     RSS     Terms of services     Privacy policy  
   
 Home     Forum     Projects     Experiments     Circuits     Theory     BLOG     PIC Tutorials     Time for Science   

Author Topic: sound amplification  (Read 16638 times)

0 Members and 1 Guest are viewing this topic.

hexe

  • Guest
sound amplification
« on: October 18, 2011, 01:03:27 AM »
Hi.I need to record some enviromental sounds (not speech).I tried my pc's microphone but it cannot even record sounds i can hear without any device.I want to hear barely noticable sounds loudly.Sound quality and distortion is not that important.Mic wil be used indoors and sounds will be recorded to pc.Can you offer me any simple solutions.I dont know much about electronics.I can make a pcb if you send schematics or simple things like that.Thanks

roneeron

  • Guest
Re: sound amplification
« Reply #1 on: October 18, 2011, 01:55:43 AM »
Hi.I need to record some enviromental sounds (not speech).I tried my pc's microphone but it cannot even record sounds i can hear without any device.I want to hear barely noticable sounds loudly.Sound quality and distortion is not that important.Mic wil be used indoors and sounds will be recorded to pc.Can you offer me any simple solutions.I dont know much about electronics.I can make a pcb if you send schematics or simple things like that.Thanks

Hello hexe,

Yes, the pc mic input is merely an ornament. It is a holdover from telephone modem days, is mono, has a live 5 volts on the plug to power a condenser type mic, so you have to watch the connections. it takes a stereo plug but 1 is tip, signal, 2 is 5volts, and three is ground. Best to  stay as far away from this as possible!

For recording I use an M-audio Fast Track Pro. This is a USB box you plug your mics or guitar into and then I use Power Tracks (PG music) to record to hard drive.

But for what you are attempting I think maybe a USB mic would work nicely, something like this?

http://www.amazon.com/gp/product/B004RE3TEE/ref=cm_cd_asin_lnk

Ron

Edit: Another option is to use a decent microphone into any thing that has a line out jack, like an old reel to reel tape recorder or small pre amp... then go into the "line in" on the PC. This has fairly respectable sound and is stereo

Best free program is "Audacity" for recording

http://audacity.sourceforge.net/




« Last Edit: October 18, 2011, 02:11:34 AM by roneeron »

_pike

  • Administrator
  • Full Member
  • *****
  • Posts: 182
Re: sound amplification
« Reply #2 on: October 18, 2011, 21:09:51 PM »
Hello and welcome to the forum what exactly you want to rec?

roneeron

  • Guest
Re: sound amplification
« Reply #3 on: October 27, 2011, 18:02:09 PM »
Hi.I need to record some enviromental sounds (not speech).I tried my pc's microphone but it cannot even record sounds i can hear without any device.I want to hear barely noticable sounds loudly.Sound quality and distortion is not that important.Mic wil be used indoors and sounds will be recorded to pc.Can you offer me any simple solutions.I dont know much about electronics.I can make a pcb if you send schematics or simple things like that.Thanks

Hello hexe,

Yes, the pc mic input is merely an ornament. It is a holdover from telephone modem days, is mono, has a live 5 volts on the plug to power a condenser type mic, so you have to watch the connections. it takes a stereo plug but 1 is tip, signal, 2 is 5volts, and three is ground. Best to  stay as far away from this as possible!

For recording I use an M-audio Fast Track Pro. This is a USB box you plug your mics or guitar into and then I use Power Tracks (PG music) to record to hard drive.

But for what you are attempting I think maybe a USB mic would work nicely, something like this?

http://www.amazon.com/gp/product/B004RE3TEE/ref=cm_cd_asin_lnk

Ron

Edit: Another option is to use a decent microphone into any thing that has a line out jack, like an old reel to reel tape recorder or small pre amp... then go into the "line in" on the PC. This has fairly respectable sound and is stereo

Best free program is "Audacity" for recording

http://audacity.sourceforge.net/

Hexe,

The ball is now in your court.



Ron

« Last Edit: October 28, 2011, 00:29:45 AM by roneeron »

hexe

  • Guest
Re: sound amplification
« Reply #4 on: October 27, 2011, 23:09:58 PM »
Sorry for replying lately

I want to record footsteps or more accurately people on the stairs of my apartment.An audio detection software (like http://www.zonetrigger.com/sound-detection/) will email me recordings whenever it detects someone so that i will know if someone is waiting for me inside the building.It may sound paranoid but there were some incidents around here lately.

I bought a cheap USB microphone as you suggested and made some recording with audacity software

audacity software (to open the recording):

http://audacity.sourceforge.net/

recording:

http://www.2shared.com/file/uvcP35JD/1_online.html

Recording is amplified with 35db gain.I cant use audacity for my purpose because it doesnt amplify sound realtime.

My flat is on the second floor.In the recording i descended to the ground floor (at about 38th second) and then began climbing.

I want to be able to hear footsteps two floors up and down.Is there any cheap and simple solution   for a much more louder and clearer recording?

specifications of the microphone i used for recording:

omni-direction
output impedance:1.4k+-30%

frequency response:50~16khz

sensitivity:-58db+-2db

operating voltage:1v~10v

current consuption:0.8ma max

s/n ratio 40db or more

Thanks

kam

  • Administrator
  • Hero Member
  • *****
  • Posts: 1849
Re: sound amplification
« Reply #5 on: October 27, 2011, 23:15:55 PM »
Oh, here is something cool! Pike showed me some time ago a very neat gadget, a small box (about 3x2x2cm if i remember well) which takes a gsm card, it has audio detection and when sound is detected, it calls a predefined number and you are able to hear live sound from your mobile! You may wanna hack this thing, put a bigger battery and a better mic and do your job. Pike will send you more details.  I tested it and i was amazed! Its a 007 staff! And i think it costs under $30

_pike

  • Administrator
  • Full Member
  • *****
  • Posts: 182

roneeron

  • Guest
Re: sound amplification
« Reply #7 on: October 28, 2011, 01:00:58 AM »

Hexe,

OK, that changes the scenario considerably. Question is then where do you have the mic? Do have access to under the stairs?

Yes, Audacity is for recording so not needed here. The program itself will monitor the computer.

What would work is a contact microphone, either on a wall or under a stair tread?

If you can get access even to the stairwell then try something like Sparkfun's ADMP401

http://www.sparkfun.com/products/9868

Ron

kam

  • Administrator
  • Hero Member
  • *****
  • Posts: 1849
Re: sound amplification
« Reply #8 on: October 28, 2011, 08:04:10 AM »
just one question out of curiosity: Why don't you use a PIR sensor instead?

hexe

  • Guest
Re: sound amplification
« Reply #9 on: October 30, 2011, 20:09:07 PM »
Oh, here is something cool! Pike showed me some time ago a very neat gadget, a small box (about 3x2x2cm if i remember well) which takes a gsm card, it has audio detection and when sound is detected, it calls a predefined number and you are able to hear live sound from your mobile! You may wanna hack this thing, put a bigger battery and a better mic and do your job. Pike will send you more details.  I tested it and i was amazed! Its a 007 staff! And i think it costs under $30

I cannot reply calls when i am in class (i am a student).

just one question out of curiosity: Why don't you use a PIR sensor instead?

Those sensors would do excellent but there are other people living in the apartment they would trigger those sensors too.Also i cannot plant anything to other floors just outside of my door because of my neighbors.

My thought is to listen recordings and see if someone entering building gets inside their flats or they dont.There arent many people staying in the building so i hope there wont be many recordings.I will set softwares sensitivity low.Before entering the building i will download recordings to my cell phone and listen them.


Hexe,

OK, that changes the scenario considerably. Question is then where do you have the mic? Do have access to under the stairs?

Yes, Audacity is for recording so not needed here. The program itself will monitor the computer.

What would work is a contact microphone, either on a wall or under a stair tread?

If you can get access even to the stairwell then try something like Sparkfun's ADMP401

http://www.sparkfun.com/products/9868

Ron

I took out the external plastic parts of my mic and it  looks like this



I planted my crappy mic in direct contact with stairs facing ground and hide it under my boots.The stairs are concrete and i can put the mic just outside of my door.Even without amplification sound of aparment door and flat doors closing can be heard this way and enough to activate software.All i need is some amplification.

I found this

http://www.spyear007.com/

and the modification (last one)

http://www.techlib.com/area_50/PTM/audio.htm

Do you think this works?If not i will consider Sparkfun's ADMP401 but there are negative comments at that page.
« Last Edit: October 30, 2011, 20:17:19 PM by hexe »

roneeron

  • Guest
Re: sound amplification
« Reply #10 on: November 01, 2011, 17:43:19 PM »


Do you think this works?If not i will consider Sparkfun's ADMP401 but there are negative comments at that page.

I just put the sparkfun mic in to show you how small you could go

Your mic looks like a standard electret... which raises the question does it have a built in Fet? if so it needs to be powered...

http://www.zen22142.zen.co.uk/Prac/ecm.htm

Then it is just a matter of searching on " electret mic preamp", to build a circuit for it

The one you give a link to might work although what you are after is a 'line level' output which I doubt this one has,

(about 1 volt, "The reference voltage for the decibel volt (0 dBV) is 1 VRMS, which is the voltage required to produce 1 milliwatt [mW] of power across a 1 kiloohm [kΩ] load.[1] The reference voltage for the decibel unloaded (0 dBu) is the voltage required to produce 1 mW of power across a 600 Ω load (approximately 0.7746 VRMS)") (wiki)

Then the output of your preamp can go into the "line in" on the computer.  Then it is a matter of setting the "level" in I am assuming Windows?

"To open Sound Recorder, click Start, point to All Programs, point to Accessories, point to Entertainment, and then click Sound Recorder.
•   
To use Sound Recorder, you must have a sound card and speakers installed on your computer. If you want to record sound, you also need a microphone."

Good luck

Ron