I need to make a special measuring timer

On Tue, 23 Apr 2013 12:49:49 GMT, N0Spam@daqarta.com (Bob Masta)
wrote:

On 22 Apr 2013 21:29:31 GMT, Jasen Betts <jasen@xnet.co.nz
wrote:

On 2013-04-21, etpm@whidbey.com <etpm@whidbey.com> wrote:
Greetings All,
So, after this long description what needs to be
done is the timing of the punches being struck needs to be measured.

Could you use a of microphones to listen to the hammers and a graphing
sound recorder software like audacity to analyse the results?

or a dedicated device could be built with a few dollars worth of parts
a centre-zero meter on a phase detector on a pair of envelope
detectors on a pair of microphones.

I like Jasen's (and George's) microphone idea. You can
probably do it with Audacity, but I'm more confident
recommending Daqarta because I know its real-time trigger
capabilities can handle this. (Audacity has an "audio"
orientation, while Daqarta is more about measurement and
instrumentation.)

You *might* be able to learn everything you need from a
single mic. I'd start out with a single mic in any case,
moving it around to see what the signal looks like in
various positions. The idea is that when the machine is set
properly you will get one big "bang", but when one hammer is
later than the other you will get a "b-bang".

This will probably be visible with a single mic that is
placed equidistant from the two points of impact. You'd
adjust the hammer timing until you get one maximal peak...
as you change relative timing the peak will get lower and
then split into two separate peaks.

You *might* be able to use an ordinary mic, plugged into the
ordinary Mic In on the sound card. If you haven't used mics
with computers, here are a few caveats: The most common
mics these days are electrets, and they are also best for
this job because they are small and have fast response (low
mass). But they need a DC bias voltage to operate, which is
provided by the Mic In connector. The Mic In connection has
more gain than Line In, but the sound card limits the
frequency response on Mic In (typically 9 kHz instead of 20+
kHz on Line In). There can also be screwy sample rate
conversion issues, since Mic In is apparently often done
with a separate A/D.

The other issue about Mic In is that it is usually mono
only, at least on systems that have a separate Line In.
Some of the newer cheapie laptops dispense with Line In
connectors and have stereo Mic In, however.

With all that, I'd still recommend trying whatever mic you
have on Mic In. If it looks promising, but for whatever
reason you feel you really need two mics (and don't have a
laptop with stereo Mic In), you will need a separate preamp
with connectors for two mics. The preamp will provide the
bias for each, and convert to Line In levels. A lot of
extra expense and fooling around, however, and I'd bet that
you don't need anything more than a simple mic.

If you want to try this with Daqarta, feel free to contact
me with any questions using the Contact links on the site.
Daqarta has a 30-day / 30-session trial period, which should
be more than enough to do this job. If you run short, let
me know and I can provide an extension. I'm also glad to
provide advice on triggering strategies or anything else.
(Note that you can right-click anything in Daqarta and
instantly see its Help topic.)

Best regards,


Bob Masta

DAQARTA v7.21
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Scope, Spectrum, Spectrogram, Sound Level Meter
Frequency Counter, Pitch Track, Pitch-to-MIDI
FREE Signal Generator, DaqMusic generator
Science with your sound card!
Greetings Bob,

I like the mike idea too. Thanks. I need to see if I can use two and
separate the sound coming from the punches. I may be able to bond the
mikes to the punches or something that the punches hit. Thanks also
for the offer of help with your software.
Eric

 

[Bob Masta]

On Tue, 30 Apr 2013 17:37:35 -0700, etpm@whidbey.com wrote:

On Tue, 23 Apr 2013 12:49:49 GMT, N0Spam@daqarta.com (Bob Masta)
wrote:

On 22 Apr 2013 21:29:31 GMT, Jasen Betts <jasen@xnet.co.nz
wrote:

On 2013-04-21, etpm@whidbey.com <etpm@whidbey.com> wrote:
Greetings All,
So, after this long description what needs to be
done is the timing of the punches being struck needs to be measured.

Could you use a of microphones to listen to the hammers and a graphing
sound recorder software like audacity to analyse the results?

or a dedicated device could be built with a few dollars worth of parts
a centre-zero meter on a phase detector on a pair of envelope
detectors on a pair of microphones.

I like Jasen's (and George's) microphone idea. You can
probably do it with Audacity, but I'm more confident
recommending Daqarta because I know its real-time trigger
capabilities can handle this. (Audacity has an "audio"
orientation, while Daqarta is more about measurement and
instrumentation.)

You *might* be able to learn everything you need from a
single mic. I'd start out with a single mic in any case,
moving it around to see what the signal looks like in
various positions. The idea is that when the machine is set
properly you will get one big "bang", but when one hammer is
later than the other you will get a "b-bang".

This will probably be visible with a single mic that is
placed equidistant from the two points of impact. You'd
adjust the hammer timing until you get one maximal peak...
as you change relative timing the peak will get lower and
then split into two separate peaks.

You *might* be able to use an ordinary mic, plugged into the
ordinary Mic In on the sound card. If you haven't used mics
with computers, here are a few caveats: The most common
mics these days are electrets, and they are also best for
this job because they are small and have fast response (low
mass). But they need a DC bias voltage to operate, which is
provided by the Mic In connector. The Mic In connection has
more gain than Line In, but the sound card limits the
frequency response on Mic In (typically 9 kHz instead of 20+
kHz on Line In). There can also be screwy sample rate
conversion issues, since Mic In is apparently often done
with a separate A/D.

The other issue about Mic In is that it is usually mono
only, at least on systems that have a separate Line In.
Some of the newer cheapie laptops dispense with Line In
connectors and have stereo Mic In, however.

With all that, I'd still recommend trying whatever mic you
have on Mic In. If it looks promising, but for whatever
reason you feel you really need two mics (and don't have a
laptop with stereo Mic In), you will need a separate preamp
with connectors for two mics. The preamp will provide the
bias for each, and convert to Line In levels. A lot of
extra expense and fooling around, however, and I'd bet that
you don't need anything more than a simple mic.

If you want to try this with Daqarta, feel free to contact
me with any questions using the Contact links on the site.
Daqarta has a 30-day / 30-session trial period, which should
be more than enough to do this job. If you run short, let
me know and I can provide an extension. I'm also glad to
provide advice on triggering strategies or anything else.
(Note that you can right-click anything in Daqarta and
instantly see its Help topic.)

Best regards,


Bob Masta

DAQARTA v7.21
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Scope, Spectrum, Spectrogram, Sound Level Meter
Frequency Counter, Pitch Track, Pitch-to-MIDI
FREE Signal Generator, DaqMusic generator
Science with your sound card!
Greetings Bob,
I like the mike idea too. Thanks. I need to see if I can use two and
separate the sound coming from the punches. I may be able to bond the
mikes to the punches or something that the punches hit. Thanks also
for the offer of help with your software.
Eric

Again, try this first with a single equidistant microphone
before you consider the hassles of using two. If you see
two distinct peaks you not only know it's going to work, but
you can probably do the whole job with that one mic.

If you only see one peak, or it's too messy to tell, it may
still be worth watching what happens as you tweak the hammer
timing... if the single peak becomes stronger, you can
assume you are moving toward coincident hits. When it
becomes broader or breaks up into separate peaks, you are
going the wrong way.

Best regards,


Bob Masta

DAQARTA v7.21
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Scope, Spectrum, Spectrogram, Sound Level Meter
Frequency Counter, Pitch Track, Pitch-to-MIDI
FREE Signal Generator, DaqMusic generator
Science with your sound card!

 

On Wed, 01 May 2013 13:15:15 GMT, N0Spam@daqarta.com (Bob Masta)
wrote:

On Tue, 30 Apr 2013 17:37:35 -0700, etpm@whidbey.com wrote:

On Tue, 23 Apr 2013 12:49:49 GMT, N0Spam@daqarta.com (Bob Masta)
wrote:

On 22 Apr 2013 21:29:31 GMT, Jasen Betts <jasen@xnet.co.nz
wrote:

On 2013-04-21, etpm@whidbey.com <etpm@whidbey.com> wrote:
Greetings All,
So, after this long description what needs to be
done is the timing of the punches being struck needs to be measured.

Could you use a of microphones to listen to the hammers and a graphing
sound recorder software like audacity to analyse the results?

or a dedicated device could be built with a few dollars worth of parts
a centre-zero meter on a phase detector on a pair of envelope
detectors on a pair of microphones.

I like Jasen's (and George's) microphone idea. You can
probably do it with Audacity, but I'm more confident
recommending Daqarta because I know its real-time trigger
capabilities can handle this. (Audacity has an "audio"
orientation, while Daqarta is more about measurement and
instrumentation.)

You *might* be able to learn everything you need from a
single mic. I'd start out with a single mic in any case,
moving it around to see what the signal looks like in
various positions. The idea is that when the machine is set
properly you will get one big "bang", but when one hammer is
later than the other you will get a "b-bang".

This will probably be visible with a single mic that is
placed equidistant from the two points of impact. You'd
adjust the hammer timing until you get one maximal peak...
as you change relative timing the peak will get lower and
then split into two separate peaks.

You *might* be able to use an ordinary mic, plugged into the
ordinary Mic In on the sound card. If you haven't used mics
with computers, here are a few caveats: The most common
mics these days are electrets, and they are also best for
this job because they are small and have fast response (low
mass). But they need a DC bias voltage to operate, which is
provided by the Mic In connector. The Mic In connection has
more gain than Line In, but the sound card limits the
frequency response on Mic In (typically 9 kHz instead of 20+
kHz on Line In). There can also be screwy sample rate
conversion issues, since Mic In is apparently often done
with a separate A/D.

The other issue about Mic In is that it is usually mono
only, at least on systems that have a separate Line In.
Some of the newer cheapie laptops dispense with Line In
connectors and have stereo Mic In, however.

With all that, I'd still recommend trying whatever mic you
have on Mic In. If it looks promising, but for whatever
reason you feel you really need two mics (and don't have a
laptop with stereo Mic In), you will need a separate preamp
with connectors for two mics. The preamp will provide the
bias for each, and convert to Line In levels. A lot of
extra expense and fooling around, however, and I'd bet that
you don't need anything more than a simple mic.

If you want to try this with Daqarta, feel free to contact
me with any questions using the Contact links on the site.
Daqarta has a 30-day / 30-session trial period, which should
be more than enough to do this job. If you run short, let
me know and I can provide an extension. I'm also glad to
provide advice on triggering strategies or anything else.
(Note that you can right-click anything in Daqarta and
instantly see its Help topic.)

Best regards,


Bob Masta

DAQARTA v7.21
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Scope, Spectrum, Spectrogram, Sound Level Meter
Frequency Counter, Pitch Track, Pitch-to-MIDI
FREE Signal Generator, DaqMusic generator
Science with your sound card!
Greetings Bob,
I like the mike idea too. Thanks. I need to see if I can use two and
separate the sound coming from the punches. I may be able to bond the
mikes to the punches or something that the punches hit. Thanks also
for the offer of help with your software.
Eric

Again, try this first with a single equidistant microphone
before you consider the hassles of using two. If you see
two distinct peaks you not only know it's going to work, but
you can probably do the whole job with that one mic.

If you only see one peak, or it's too messy to tell, it may
still be worth watching what happens as you tweak the hammer
timing... if the single peak becomes stronger, you can
assume you are moving toward coincident hits. When it
becomes broader or breaks up into separate peaks, you are
going the wrong way.

Best regards,


Bob Masta

DAQARTA v7.21
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Scope, Spectrum, Spectrogram, Sound Level Meter
Frequency Counter, Pitch Track, Pitch-to-MIDI
FREE Signal Generator, DaqMusic generator
Science with your sound card!
Thanks Bob, I'll try the single mic first.

Eric