seeking schematics or plans to build a stereo analog volume meter (toplug into pc speaker headphone

[[email protected]]

I would like to build an analog volume meter (moving needle type)
using moving needle gauges like this
http://en.wikipedia.org/wiki/Image:VU_Meter.jpg
scavenged from a dead mixer's VU meter.

It would plug into the headphone jack on a set of computer speakers
and monitor the right/left sound volumes independently.

Can anyone point me to a good website or book with schematics or plans
on building this?


PS I would also be interested in building a frequency meter (also
would be plugged into computer speakers and display the pitch/
frequency of a pure sin wave coming from the computer's sound card). I
got several replies but they were pretty technical and I have not
found any complete plans for such a device. If any can suggest a good
web site or book that would be great. Thanks

BobG:

That's a tachometer. A lo pass filter, a comparator, a oneshot, a
capacitor, and a meter on a trimpot. Every zero crossing, the
comparator fires the oneshot, the cap integrates the pulses, and the
meter shows the freq. Cal it with sine waves.... no harmonics.

linnix:
Or a $2 micro averaging the DCT, FFT or XYZ (forgot the name of that
spectral analyser).

whit3rd:
Phase-lock loops like 74HC4046 can lock onto an audio
frequency, and the follower in it has an output voltage
proportional to frequency. That's about $0.60 from your budget;
a good analog moving-needle meter will suck up the rest of it.

 

[William Sommerwerck]

I would like to build an analog volume meter (moving needle
type) using moving needle gauges like this
http://en.wikipedia.org/wiki/Image:VU_Meter.jpg
scavenged from a dead mixer's VU meter.

Why do you need this, or think you need this? It might look nice, but will
it tell you what you need to know?

 

[Richard Crowley]

I would like to build an analog volume meter (moving needle type)
using moving needle gauges like this
http://en.wikipedia.org/wiki/Image:VU_Meter.jpg
scavenged from a dead mixer's VU meter.

It would plug into the headphone jack on a set of computer speakers
and monitor the right/left sound volumes independently.

Can anyone point me to a good website or book with schematics or plans
on building this?

It is a pretty simple circuit, but it greatly depends on exactly
what your meters are. Get youself a couple of meters first,
and then come back and ask specifically for how to hook
them up. It would be very helpful to know what they came
out of, and for bonus points, the circuit diagram of where
they came from.

PS I would also be interested in building a frequency meter (also
would be plugged into computer speakers and display the pitch/
frequency of a pure sin wave coming from the computer's sound card). I
got several replies but they were pretty technical and I have not
found any complete plans for such a device. If any can suggest a good
web site or book that would be great. Thanks

Forget it. It is neither practical nor particularly useful.
Unless you can give us a good explanation of what you
think you want to do with it, nobody can help you.

(posted from rec.audio.tech)

 

[Scott Dorsey]

I would like to build an analog volume meter (moving needle
type) using moving needle gauges like this
http://en.wikipedia.org/wiki/Image:VU_Meter.jpg
scavenged from a dead mixer's VU meter.

Why do you need this, or think you need this? It might look nice, but will
it tell you what you need to know?[/QUOTE]

And if you really need an actual VU meter, you won't find it on too many
consoles being scavenged these days, sad to say.
--scott

 

[dizzy]

I would like to build an analog volume meter (moving needle type)
using moving needle gauges like this
http://en.wikipedia.org/wiki/Image:VU_Meter.jpg
scavenged from a dead mixer's VU meter.

It would plug into the headphone jack on a set of computer speakers
and monitor the right/left sound volumes independently.

Can anyone point me to a good website or book with schematics or plans
on building this?

How about LED bar-graph VU meter? Fairly easy to make, using these:

http://www.national.com/mpf/LM/LM3915.html

or

http://www.national.com/mpf/LM/LM3916.html

Check the full datasheet for example circuits.

 

[Paul Stamler]

I would like to build an analog volume meter (moving needle type)
using moving needle gauges like this
http://en.wikipedia.org/wiki/Image:VU_Meter.jpg
scavenged from a dead mixer's VU meter.

It would plug into the headphone jack on a set of computer speakers
and monitor the right/left sound volumes independently.

Can anyone point me to a good website or book with schematics or plans
on building this?

I believe I published a design for a buffered VU meter somewhere around 1993
in Audio Amateur magazine, which is now known as audioXpress. It's really
very simple; for an unbalanced line (like the headphone jack) all you need
is an opamp (half of a TL072 works fine), a couple of resistors, and a pot
to adjust the calibration. Connect the output of the opamp to the VU meter
through a 3.62k resistor and you're home free (okay, you need something to
power the opamp like a cheap balanced power supply or a couple of 9V
batteries). If you have a real VU meter, there you are.

Of course, we don't know if your "VU" meter is a real VU meter, which has
certain defined ballistics that are specified in ANSI technical standards.
Can you tell us from what broken mixer you scavenged the meter?

PS I would also be interested in building a frequency meter (also
would be plugged into computer speakers and display the pitch/
frequency of a pure sin wave coming from the computer's sound card). I
got several replies but they were pretty technical and I have not
found any complete plans for such a device. If any can suggest a good
web site or book that would be great. Thanks

Probably the easiest way to do that is not to build it. Instead, go buy a
digital voltmeter (DVM) which has a frequency scale on it.

Peace,
Paul

 

[linnix]

How about LED bar-graph VU meter? Fairly easy to make, using these:

For small displays, LED is difficult to have fine resolutions.

Color backlite LCD is a much better option.

For example:

http://linnix.com/lcd-meter.jpg

is a color LCD display for one of our customer.

You can drive it with an LCD uC running a Goertzel filter on the
selected frequency. uC + LCD for $5 in volume.

 

[Scott Dorsey]

How about LED bar-graph VU meter? Fairly easy to make, using these:

http://www.national.com/mpf/LM/LM3915.html

Comes only vaguely close to meeting VU ballistics specs, which can be
very annoying at times. Fine for rough work, though.

Vellemann makes some inexpensive LED meter kids.
--scott

 

[DaveM]

Comes only vaguely close to meeting VU ballistics specs, which can be
very annoying at times. Fine for rough work, though.

Vellemann makes some inexpensive LED meter kids.
--scott

If the OP is determined to build something to use his analog meters, I suggest
the project at http://sound.westhost.com/project55.htm. Seems to be a
reasonable circuit and gives a decent description as well.

--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate characters in the
address)

"In theory, there isn't any difference between theory and practice. In
practice, there is." - Yogi Berra

 

[Mike Rivers]

If the OP is determined to build something to use his analog meters, I suggest
the project athttp://sound.westhost.com/project55.htm. Seems to be a
reasonable circuit and gives a decent description as well.

My humble apologies. I thought I was reading the same question that he
asked a few days ago when he wanted to use an analog VU meter to
display pitch. I see that here he's looking to display level.
Different question, different answer, and this one has an easier
answer.

 

[Dave]

I would like to build an analog volume meter (moving needle type)
using moving needle gauges like this
http://en.wikipedia.org/wiki/Image:VU_Meter.jpg
scavenged from a dead mixer's VU meter.

It would plug into the headphone jack on a set of computer speakers
and monitor the right/left sound volumes independently.

Can anyone point me to a good website or book with schematics or plans
on building this?


PS I would also be interested in building a frequency meter (also
would be plugged into computer speakers and display the pitch/
frequency of a pure sin wave coming from the computer's sound card). I
got several replies but they were pretty technical and I have not
found any complete plans for such a device. If any can suggest a good
web site or book that would be great. Thanks


That's a tachometer. A lo pass filter, a comparator, a oneshot, a
capacitor, and a meter on a trimpot. Every zero crossing, the
comparator fires the oneshot, the cap integrates the pulses, and the
meter shows the freq. Cal it with sine waves.... no harmonics.

linnix:
Or a $2 micro averaging the DCT, FFT or XYZ (forgot the name of that
spectral analyser).

whit3rd:
Phase-lock loops like 74HC4046 can lock onto an audio
frequency, and the follower in it has an output voltage
proportional to frequency. That's about $0.60 from your budget;
a good analog moving-needle meter will suck up the rest of it.

test

 

[sycochkn]

test

A crystal controlled monostable multivibrator driving an analog meter. that
is more like 10 bucks without the meter. It can be calibrated without an
input signal. or by inputting a signal beyond its range.


Bob

Bob