Michael 2727 sound detector circuit

hippy

Technical Support
Staff member
#2
From the Royal Society for the Protection of ASCII Art

Michael--the ascii art that you supplied in this thread: http://www.picaxeforum.co.uk/showthread.php?t=7152&highlight=sound+sensor
is scrambled. You wouldn't happen to still have that available for reposting would you?

P.S. Technical--it would be really nice if the ascii art and code from the old postings could be made to look right.
The easiest way to get at original ASCII Art at present is to do a View Page Source, locate the Art ( it still has correct spacing ), copy 'n' paste to a text Editor ( the Forum post box isn't a mono-spaced font ), edit the original post then copy the new code in.

All the HTML decoration has to be deleted or changed, but it's not too onerous, and could be easily automated. I'm thinking of writing an application which can have a page URL pasted into it which will auto-recover the ASCII Art. In the meantime, assuming I've introduced no translation errors by hand ...

Code:
              o         o   5V       o
              |         |            |
              |         |            |
             .-.       .-.           |
             | | 22K   | | 1Meg      |
             | |       | |           |
             '-'       '-'           |
              |         |            |
              |         |         3|\| LM358 1/2        22K
              o--------------------|+\                  ___        OUT
              |         |          |  >----->|------o--|___|--o----o
              |         |      .---|-/ 1    1N4148  |         |
              |         o      |  2|/|              |         |
              |         |      |     |4             |         |
         _    |         |      |     |              |         |
      | / \---o        .-.     |     |          1uF |        .-.
      |(Mic)           | |<----'     |             ---       | |47K
      | \_/---o        | |           |             ---       | |
              |        '-' 100K      |              |        '-'
              |         |            |              |         |
              |         |            |              |         |
              |         |            |              |         |
              o         o   0V       o              o         o

(created by AACircuit v1.28.6 beta 04/19/05 www.tech-chat.de)

The 1uF is an Electro +pos ^ top. Somewhere around 2/3 Pot rotation will make the O/P on full.
 

lbenson

Senior Member
#3
Thank you, hippy. I had tried cutting and pasting from the post view, but the spacing had already been stripped out. Cutting from the "source view" looks like it does the trick. This will be most useful if Rev-Ed cannot do it automagically, but it will be very confusing for beginners searching the archives.
 
#4
Try this I think the other version was missing a Cap and Resistor.

There are much more efficient ways to use the OP Amp, including
using the other half for extra gain etc.
This circuit uses the minimum amount of components to get a
useable result in the end. In practicle use it runs rings around
many high gain circuits as a thump or knock detector as low
level or constant level sound did not activate the relay it was
designed to operate.
Code:
   5V to 15V+
   o-----------------o--------o
   |                 |        |
   |                .-.       |
  .-.           1   | |       |
  | | 22K       Meg | |       |
  | |               '-'       |
  '-'                |        |
   |       1.0µF     o        | 1/2 LM358 or Equiv.
   |        ||       |      |\|
   o--------||---o---|------|-\    1N4148   Output >
   |        ||   |   |      |  >----->|--o-------
   |            .-. .-.    -|+/          |
   |+  _     10 | | | |<--/ |/|          |
   '--/ \ |  Meg| | | |       |        + | 1.0µF
     (Mic)|     '-' '-' 100K  |         ---
   ,--\_/ |      |   |  Pot   |         ---
   |             |   |        |          |
   |             |   |        |          |
   o-------------o---o--------o----------o
   0v Neg
(created by AACircuit v1.28.6 beta 04/19/05 www.tech-chat.de)
 

lbenson

Senior Member
#5
Thanks, Michael. I'm hoping to detect a fairly loud pump running--do you think this can be tuned to do that? How would I best monitor the output? ADC or might it be tuned to give a logic level for the sound I'm looking to capture?
 
#6
The original design was was set up as a peak detector.
The Doide and Cap on the output work as a HOLD circuit
which was driving a 12V Relay via a 2N7000 Mosfet.
If you make the output Capacitor 1µF to 10µF you can
get the relay to latch for 1/2 Sec to a few Secs.
( a BJT transistor will drain the capacitor v-quickly )

It's hard to say what the pump will make it do, try it.
 
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