Listening to the microphone

[Rod]

This popped up on our other forum. Its all to do with radioactivity and listening to and analysing a Geiger counters output. This code just listens to the mic in mono at 8bit sampling. Just a basic start but amazing how easy it was to get to the sound input.


'experimental Radiometer by [e-mail]
   'uses MMI to stream audio from Mic
   '8bit audio is set for faster parsing
   'blips from giger counter are heard but
   'need parsed, recorded and displayed
   'currently samples at 50ms

   nomainwin
   WindowWidth = 450
   WindowHeight = 130
   UpperLeftX=int((DisplayWidth-WindowWidth)/2)
   UpperLeftY=int((DisplayHeight-WindowHeight)/2)
   graphicbox #1.bar,  23,  50, 400,  20
   open "Radiometer" for window_nf as #1
   #1.bar "down; fill white; flush"
   #1.bar "backcolor green"
   #1 "trapclose [quit]"



   [startRecording]
   'set the .wav recording format
   bitspersample = 8
   channels = 1
   samplespersec = 8000
   alignment = bitspersample * channels / 8
   bytespersec = alignment * samplespersec

   params$ = " bitspersample " + STR$(bitspersample)+_
           " channels " + STR$(channels) +_
           " alignment " + STR$(alignment) + _
           " samplespersec " + STR$(samplespersec) + _
           " bytespersec " + STR$(bytespersec)

   'open wav audio to listen to the wavaudio
   r$=mciSendString$("open new type waveaudio alias wav")
   r$=mciSendString$("set wav "+params$)

   timer 50, [readVolume]
   wait

   [readVolume]
   #1.bar "discard ; backcolor white"
   #1.bar "boxfilled 400 25 ; backcolor green"
   r$=mciSendString$("status wav level")
   level = val(r$)
   'print level
   #1.bar "boxfilled ";level;" 20; discard"
   wait


   [quit] 'End the program
   timer 0
   r$=mciSendString$("close wav")
   close #1
   end

Function mciSendString$(s$)
   'Buffer will contain a return string from
   'the function, if there is one.
   buffer$=space$(1024)+chr$(0)
   calldll #winmm,"mciSendStringA",s$ as ptr,buffer$ as ptr,_
   1028 as long, 0 as long, r as long
   'truncate returned string at null character
   buffer$=left$(buffer$, instr(buffer$, chr$(0)) - 1)
   if r>0 then
       mciSendString$="error"
   else
   mciSendString$=buffer$
   end if
End Function




[Brandon Parker]

Rod,
I like it! Now, you just need an XY plot with teensy-tiny litter bar graphs.

Singing at my laptop (surprisingly it didn't just break) was not causing the meter to go up very noticeably, but I made this change to the line that draws the box and it made it much better for my viewing purposes. It just "feels" better than a linear scale here...

#1.bar "boxfilled ";(level^1.25);" 20; discard"


{:0)

Brandon Parker

[tenochtitlanuk]

Unfortunately the MCI calls don't work for me under Linux/Wine.

re Rod's comments in JB Forum- I'll certainly be playing with the wav-file being repeatedly created and used. In my experience audio clicks always are a decaying sin wave. Only the original electronic signal is a single logic-level pulse.

Incidentally we're heading towards a Geiger 'ratemeter'. A 'radiometer' was a lightweight paddle wheel that rotated when you shone a light on its vanes, whech were black on one side and white/silvered on the other, via heating effects and ( possibly) photon momentum effects.

[Rod]

As we approach lb5 we are going to need to know how to access Linux media resources.

[tenochtitlanuk]

Could not resist coding a 'recreation' of a Dekatron Geiger counter- just love the neon glow.



If you run it, the Dekatrons step at random intervals and you hear the 'click' Once past one thousand the electromechanical counter copes. I havent run it up to the available full 9 digit display- I'll be long-dead before it gets there!

Will put a page on my website in the next couple of days.

EDIT
Dekatron Counter.

[Jim]

I played with some of the code on the Radio meter and I think it responds a little faster now.

here the lines I changed :

#1.bar "boxfilled ";(level^1.10);" 20; discard"

buffer$=space$(835)+chr$(0)

timer 40, [readVolume]

also changed the text window and Graphic bar parms to a shorte Length but same width

WindowWidth = 250
WindowHeight = 130

graphicbox #1.bar, 23, 50, 200, 20

it is a totally Awesom Program, Cudos to you my friend!

Jim

PS: another cool mod would be to make it so that when the volume level is low, the Bar is green

and then at the mid point it turns to yellow , and then red for high volume.

like this :

-------------------------------------------------------

|  Green              | Yellow              |  red                  

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