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can a stamp read current or voltage from a microphone

ArchiverArchiver Posts: 46,084
edited 2000-08-10 21:14 in General Discussion
Hello,


I want to make a loud-noise detector and I
was wondering if I could just hook up a
cheap radioshack microphone and use a
stamp to measure the current or voltage?

Does a microphone alone put out enough
of anything to measure??

If so, what would be the easiest to measure,
voltage or current??

And how would you do it with a stamp,
say measure a current?

I don't want to add an amplifier, I want something
very simple, fewest parts, and I haven't bought a
microphone yet. If there is a special one available,
maybe this would do it. Perhaps there are tiny microphones
with amps built in?? radioshack grade cheapies

I thought if this would work, I could just
adjust a number or check for a signal
of a certain level to corespond to the
loudness of the noise. This way I might
be able to adjust the sensitivity of it,

Can this be done, simply?
Once my noise detector senses the noise, it
will close a relay to do whatever.

Thank in advance.

Rick

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2000-08-09 20:55
    er, uh

    I think a condenser microphone is what I'm looking
    for. Can a condenser microphone be hooked up
    to a stamp to detect sounds???


    Original Message
    From: "rad0" <rden25@m...>
    To: "stampers!" <basicstamps@egroups.com>
    Sent: Wednesday, August 09, 2000 10:42 AM
    Subject: [noparse][[/noparse]basicstamps] can a stamp read current or voltage from a microphone


    > Hello,
    >
    >
    > I want to make a loud-noise detector and I
    > was wondering if I could just hook up a
    > cheap radioshack microphone and use a
    > stamp to measure the current or voltage?
    >
    > Does a microphone alone put out enough
    > of anything to measure??
    >
    > If so, what would be the easiest to measure,
    > voltage or current??
    >
    > And how would you do it with a stamp,
    > say measure a current?
    >
    > I don't want to add an amplifier, I want something
    > very simple, fewest parts, and I haven't bought a
    > microphone yet. If there is a special one available,
    > maybe this would do it. Perhaps there are tiny microphones
    > with amps built in?? radioshack grade cheapies
    >
    > I thought if this would work, I could just
    > adjust a number or check for a signal
    > of a certain level to corespond to the
    > loudness of the noise. This way I might
    > be able to adjust the sensitivity of it,
    >
    > Can this be done, simply?
    > Once my noise detector senses the noise, it
    > will close a relay to do whatever.
    >
    > Thank in advance.
    >
    > Rick
    >
    >
    >
    >
    >
    >
  • ArchiverArchiver Posts: 46,084
    edited 2000-08-09 23:41
    Rick,

    If the sound is REALLY loud (gunshot?), you might look into piezoelectric
    plastic vibration sensors. Some of these may have enough output voltage to
    drive the Stamp directly.

    Electret mics require clean DC voltage for operation. It's probably best to
    use an old-fashioned crystal/ceramic mic for this job, but no microphone,
    barefoot, is likely to produce enough output voltage for the Stamp. Also,
    your sound duration may be too short to guarantee detection (the Stamp may
    be doing something else when the sound impulse arrives). Both problems
    could be solved by a comparator chip (e.g. LM311) with a diode and
    capacitor to stretch the logic output signal duration. You could use the
    comparator's reference voltage input (or a 'volume' control) to vary the
    detection threshold.

    >I want to make a loud-noise detector and I
    >was wondering if I could just hook up a
    >cheap radioshack microphone and use a
    >stamp to measure the current or voltage?
    >
    >Does a microphone alone put out enough
    >of anything to measure??
    >
    >If so, what would be the easiest to measure,
    >voltage or current??
    >
    >And how would you do it with a stamp,
    >say measure a current?
    >
    >I don't want to add an amplifier, I want something
    >very simple, fewest parts, and I haven't bought a
    >microphone yet. If there is a special one available,
    >maybe this would do it. Perhaps there are tiny microphones
    >with amps built in?? radioshack grade cheapies
    >
    >I thought if this would work, I could just
    >adjust a number or check for a signal
    >of a certain level to corespond to the
    >loudness of the noise. This way I might
    >be able to adjust the sensitivity of it,
    >
    >Can this be done, simply?
    >Once my noise detector senses the noise, it
    >will close a relay to do whatever.

    Mike Hardwick, for Decade Engineering -- <http://www.decadenet.com>
    Manufacturer of the famous BOB-II Serial Video Text Display Module!
  • ArchiverArchiver Posts: 46,084
    edited 2000-08-10 16:38
    Thanks Mike,

    What I want to make is a loud noise detector.
    Hopefully, no gunshots...

    I guess I want to make a 'clapper' for loud noises.
    How does the clapper work anyway, maybe I could
    just do that...

    Rick


    Original Message
    From: "Mike Hardwick" <decade@w...>
    To: <basicstamps@egroups.com>
    Sent: Wednesday, August 09, 2000 5:41 PM
    Subject: Re: [noparse][[/noparse]basicstamps] can a stamp read current or voltage from a
    microphone


    > Rick,
    >
    > If the sound is REALLY loud (gunshot?), you might look into piezoelectric
    > plastic vibration sensors. Some of these may have enough output voltage to
    > drive the Stamp directly.
    >
    > Electret mics require clean DC voltage for operation. It's probably best
    to
    > use an old-fashioned crystal/ceramic mic for this job, but no microphone,
    > barefoot, is likely to produce enough output voltage for the Stamp. Also,
    > your sound duration may be too short to guarantee detection (the Stamp may
    > be doing something else when the sound impulse arrives). Both problems
    > could be solved by a comparator chip (e.g. LM311) with a diode and
    > capacitor to stretch the logic output signal duration. You could use the
    > comparator's reference voltage input (or a 'volume' control) to vary the
    > detection threshold.
    >
    > >I want to make a loud-noise detector and I
    > >was wondering if I could just hook up a
    > >cheap radioshack microphone and use a
    > >stamp to measure the current or voltage?
    > >
    > >Does a microphone alone put out enough
    > >of anything to measure??
    > >
    > >If so, what would be the easiest to measure,
    > >voltage or current??
    > >
    > >And how would you do it with a stamp,
    > >say measure a current?
    > >
    > >I don't want to add an amplifier, I want something
    > >very simple, fewest parts, and I haven't bought a
    > >microphone yet. If there is a special one available,
    > >maybe this would do it. Perhaps there are tiny microphones
    > >with amps built in?? radioshack grade cheapies
    > >
    > >I thought if this would work, I could just
    > >adjust a number or check for a signal
    > >of a certain level to corespond to the
    > >loudness of the noise. This way I might
    > >be able to adjust the sensitivity of it,
    > >
    > >Can this be done, simply?
    > >Once my noise detector senses the noise, it
    > >will close a relay to do whatever.
    >
    > Mike Hardwick, for Decade Engineering -- <http://www.decadenet.com>
    > Manufacturer of the famous BOB-II Serial Video Text Display Module!
    >
    >
    >
  • ArchiverArchiver Posts: 46,084
    edited 2000-08-10 17:25
    >I guess I want to make a 'clapper' for loud noises.
    >How does the clapper work anyway, maybe I could
    >just do that...

    >>I don't want to add an amplifier, I want something
    >>very simple, fewest parts, and I haven't bought a
    >>microphone yet. If there is a special one available,
    >>maybe this would do it. Perhaps there are tiny microphones
    >>with amps built in?? radioshack grade cheapies

    The trick is to do it without an amplifier. I think some of the companies
    like Marlin P Jones have kits that include both the mike and the amplifier
    and a little circuit board.

    Electret mikes have a preamplifier built in, but still they will only
    provide a fraction of a volt for a loud noise. The amplifier could be a
    pretty simple sample and hold amplifier that could be reset by the stamp.
    This is just an x100 non-inverting amplifier, built with something like an
    CA3130 op amp. The diode and the capacitor at the output hold onto a short
    loud pulse until the Stamp can get around to sampling it. Then the Stamp
    discharges the capacitor (LOW 0) and goes back to input mode (INPUT 0).

    ;
    o
    Vdd
    | |
    ;
    ; |
    |mike | 0.1 |\|
    | |---||-o
    |+\ 4148
    | | | | >-o->|--o
    P0
    '
    ' | ;--|-/ | |
    | 1M | | |/ | |
    o--/\/\---' | | |
    | | | |
    o--/\/\
    o--/\/\-' |
    | 1k 100k |
    | === 0.1
    | |
    | |
    '
    o
    Vss

    Tracy Allen
    Electronically Monitored Ecosystems
    http://www.emesystems.com
  • ArchiverArchiver Posts: 46,084
    edited 2000-08-10 21:14
    Rick,

    Just guessing, but I think the 'Clapper' consists of a relay that's
    controlled by an amplifier and rectifier (or comparator) driving a
    flip-flop. Somewhere in the microphone amplifier circuit, they probably
    added high-pass or resonant filtering to make it selective for impulse
    noise. Glass breakage detectors are similar. You might find one cheap at a
    local car stereo shop, but the output may be 12V instead of the 5V you need
    for Stamp input. If the output is open-collector, you're in business.

    >I guess I want to make a 'clapper' for loud noises.
    >How does the clapper work anyway, maybe I could
    >just do that...

    Mike Hardwick, for Decade Engineering -- <http://www.decadenet.com>
    Manufacturer of the famous BOB-II Serial Video Text Display Module!
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