Change frequency based on voltage

[SS]

Hi all,

I am getting an ac signal from ultrasonic rx. it is between .5V to 5V. I
need to make a circuit that would
sound an alarm with different tones based on the input voltage. How can I do
that.

Thx for the help.

Sal

 

[John Fields]

On Tue, 30 Mar 2004 22:23:03 GMT, "SS" <saleem.qamar@verizon.net>
wrote:

Hi all,

I am getting an ac signal from ultrasonic rx. it is between .5V to 5V. I
need to make a circuit that would
sound an alarm with different tones based on the input voltage. How can I do
that.

---
First, you need to determine how many different voltage levels you
want to detect. That will determine the number of different tones
you'll need to generate. Once you decide that, you'll want to rectify
and filter the AC signal so that you have a DC signal with a voltage
which varies as the input signal varies, then use as many voltage
comparators as required to switch (say) resistances in and out of the
tone generating circuitry in order to get the different tones.

--
John Fields

 

[Watson A.Name \"Watt Sun]

John Fields wrote:

On Tue, 30 Mar 2004 22:23:03 GMT, "SS" <saleem.qamar@verizon.net
wrote:

Hi all,

I am getting an ac signal from ultrasonic rx. it is between .5V to 5V. I
need to make a circuit that would
sound an alarm with different tones based on the input voltage. How can I do
that.

---
First, you need to determine how many different voltage levels you
want to detect. That will determine the number of different tones
you'll need to generate. Once you decide that, you'll want to rectify
and filter the AC signal so that you have a DC signal with a voltage
which varies as the input signal varies, then use as many voltage
comparators as required to switch (say) resistances in and out of the
tone generating circuitry in order to get the different tones.

I can't understand why all the complexity is needed, switching res's
etc. All that he has to do is use a simple two transistor metronome
circuit that will go from a slow clicking to a high pitched squeal with
a change in the input voltage. Feed his rectified AC into that and you
have a nearly infinite range of tones.

 

[MikeM]

SS wrote:

Hi all,

I am getting an ac signal from ultrasonic rx. it is between .5V to 5V. I
need to make a circuit that would
sound an alarm with different tones based on the input voltage. How can I do
that.

Thx for the help.

Sal

LOts of these out there:
http://web.haystack.mit.edu/SRT/files/ad654.pdf

do a google search for "voltage to frequency converter" (include ")

 

[John Fields]

On Tue, 30 Mar 2004 15:29:57 -0800, "Watson A.Name \"Watt Sun - the
Dark Remover\"" <NOSPAM@dslextreme.com> wrote:

John Fields wrote:
On Tue, 30 Mar 2004 22:23:03 GMT, "SS" <saleem.qamar@verizon.net
wrote:


Hi all,

I am getting an ac signal from ultrasonic rx. it is between .5V to 5V. I
need to make a circuit that would
sound an alarm with different tones based on the input voltage. How can I do
that.


---
First, you need to determine how many different voltage levels you
want to detect. That will determine the number of different tones
you'll need to generate. Once you decide that, you'll want to rectify
and filter the AC signal so that you have a DC signal with a voltage
which varies as the input signal varies, then use as many voltage
comparators as required to switch (say) resistances in and out of the
tone generating circuitry in order to get the different tones.

I can't understand why all the complexity is needed, switching res's
etc. All that he has to do is use a simple two transistor metronome
circuit that will go from a slow clicking to a high pitched squeal with
a change in the input voltage. Feed his rectified AC into that and you
have a nearly infinite range of tones.

---
"Alarm", to me, indicates that he wants only a few tones to indicate a
very limited number of conditions. Using a continuously variable VCO
would tend to muddy the boundaries between alarm events and lead to
confusion as to what was happening unless the listener happened to
have close to perfect pitch. As far as complexity goes, if he's only
looking for a couple of tones we're probably looking at an LM393, a
555, a speaker and a handful of resistors.

However, how about if we reserve judgement until he responds?

--
John Fields

 

[Shireen Qamar]

Thx for the reply,

Yes I only want a few tones to tell me when i am getting close to an object.
Can any one send me sampkle circuit pls. using 393 and 555.

Thx

Sal

"John Fields" <jfields@austininstruments.com> wrote in message
news:406e30de.637789484@news.texas.net...

On Tue, 30 Mar 2004 15:29:57 -0800, "Watson A.Name \"Watt Sun - the
Dark Remover\"" <NOSPAM@dslextreme.com> wrote:

John Fields wrote:
On Tue, 30 Mar 2004 22:23:03 GMT, "SS" <saleem.qamar@verizon.net
wrote:


Hi all,

I am getting an ac signal from ultrasonic rx. it is between .5V to 5V.
I
need to make a circuit that would
sound an alarm with different tones based on the input voltage. How can
I do
that.


---
First, you need to determine how many different voltage levels you
want to detect. That will determine the number of different tones
you'll need to generate. Once you decide that, you'll want to rectify
and filter the AC signal so that you have a DC signal with a voltage
which varies as the input signal varies, then use as many voltage
comparators as required to switch (say) resistances in and out of the
tone generating circuitry in order to get the different tones.

I can't understand why all the complexity is needed, switching res's
etc. All that he has to do is use a simple two transistor metronome
circuit that will go from a slow clicking to a high pitched squeal with
a change in the input voltage. Feed his rectified AC into that and you
have a nearly infinite range of tones.

---
"Alarm", to me, indicates that he wants only a few tones to indicate a
very limited number of conditions. Using a continuously variable VCO
would tend to muddy the boundaries between alarm events and lead to
confusion as to what was happening unless the listener happened to
have close to perfect pitch. As far as complexity goes, if he's only
looking for a couple of tones we're probably looking at an LM393, a
555, a speaker and a handful of resistors.

However, how about if we reserve judgement until he responds?

--
John Fields

 

[CFoley1064]

Subject: Re: Change frequency based on voltage
From: "Shireen Qamar" sqamar90@hotmail.com
Date: 3/30/2004 10:07 PM Central Standard Time
Message-id: <Ztrac.22399$u_2.13029@nwrddc01.gnilink.net

Thx for the reply,

Yes I only want a few tones to tell me when i am getting close to an object.
Can any one send me sampkle circuit pls. using 393 and 555.

Thx


Sal

I would guess from your post that you want an output dependent on the amplitude
of the AC signal, which I'm going to assume is around 40 KHz. I'm going to
assume you're talking about a signal that's .5VAC (1.4V p.p.) to 5VAC (14V
p.p.). You want the tone to start when the input voltage is about 0.5VAC, get
a second, higher tone when it's about halfway to 5VAC, and a higher tone when
it's above 5VAC. This is a made-to-order "Radio Shack" type solution (view in
fixed font or M$ Notepad):

12VDC
+
| ___ 7.0V ___ 4.0V ___ 0.5V ___
'---|___|---o-|___|---o--|___|----o--|___|---.
| | | |
| | | |
1N34 | | | ===
o--->|-o---o--------o---------o-----------. | GND
| | | | | | | |
.1uF--- .-. | | | | | |
o---. --- | |1M | | | | | |
| | | | -----. -----. .-----.
| | '-' \- +/ \- +/ 12VDC \+ -/
| | | \ / \ / + \ /
====== === V V | V
GNDGND GND | | .-. | VCC
1N914 - 1N914 - | | '--. +
^ ^ | | | |
| | '-' | |
.-. .-. | .--o---o---. 40 ohm
27K| | 27K| | o-. | 4 8 | spkr
| | | | | '----o 7 | 100uF
'-' '-' .-. | | +|# __ /|
| | | | | 3 o---|#--| | |
.----o---------' | | .---o 6 | |#.-|__| |
| | '-' | | | | \|
.01uF | | | | | LM555 | |
--- | o--o---o 2 | ===
--- | | | | GND
| | --- | 5 1 |
| | --- '--o---o---'
=== | | | |
GND '-------------===--------' ===
GND GND

created by Andy´s ASCII-Circuit v1.24.140803 Beta www.tech-chat.de

Here's how this works. The 1N34 diode half-wave rectifies the signal, and the
1M resistor with the cap sets up a time constant of 10 ms (plenty responsive to
changes in amplitude, but very little ripple for 40 KHz). That signal goes to
the three comparators. The one on the right is connected so that it will be
output low below 0.5V (subtract about 0.2V forward drop for the 1N34), which
means that below that voltage the reset pin of the 555 will be off, and on
above that minimum voltage.

The other two comparators are set up so that, when they go high, they will
steal current from the control voltage at pin 5. The 555 is internally set up
with 3 ea. 5K resistors set as a voltage divider between Vcc and GND. The
control voltage is supposed to be 2/3 Vcc. By stealing current from the node,
you will make it so the upper and lower trip points of the 555 will be at
correspondingly lower voltages. This will result in the 555 running as an
astable oscillator much faster. For the output, use a higher impedance speaker
(say, 40 ohms or so) or use a series resistor with the speaker.

If you only need two tones instead of 3, you can eliminate the middle
comparator, which will get you a two chip solution. Not knowing specifics,
I'll leave the maths to choose the resistors and cap for the voltage divider
and 555 to you -- can't take all the fun.

Oh, yes -- would you like fries with that?

Good luck
Chris

 

[John Fields]

On Wed, 31 Mar 2004 04:07:21 GMT, "Shireen Qamar"
<sqamar90@hotmail.com> wrote:

Thx for the reply,

Yes I only want a few tones to tell me when i am getting close to an object.
Can any one send me sampkle circuit pls. using 393 and 555.

---
I can, but I need to know whether what you call the "ac signal" is the
echo or not. Actually, it would be nice to know _exactly_ what it is
and how it changes with range.

--
John Fields

 

[Genome]

"SS" <saleem.qamar@verizon.net> wrote in message
news:brmac.22262$u_2.12569@nwrddc01.gnilink.net...
| Hi all,
|
| I am getting an ac signal from ultrasonic rx. it is between .5V to 5V.
I
| need to make a circuit that would
| sound an alarm with different tones based on the input voltage. How
can I do
| that.
|
| Thx for the help.
|
| Sal
|
|

If you are measuring distance, which is what a later post of your
suggests then what you might try doing is.....

Set up an RC oscillator based on 1 off 6 of CMOS 4069 to go buzz at
40KHz. Buffer that with 3 off 6 of the 4069 to drive your transmitter.
Use the spare 2 off gates, the first as a linear amplifier for the
reciever follwed by the next to square up the output of the 4069.

Take an exclusive or gate, CMOS 4070. Use one of the gates to compare
the relative phase of the signal into your transmitter and from your
reciever.

Then low pass filter that and add the circuit that goes beep.

I think sound is 440m/s at ground zero.

DNA

 

[John Woodgate]

I read in sci.electronics.design that Genome <Genome@nothere.com> wrote
(in <jVBac.1481$4N3.737@newsfe1-win&gt about 'Change frequency based on
voltage', on Wed, 31 Mar 2004:

I think sound is 440m/s at ground zero.

Try 330. But you get different answers from people in different
countries, depending on what ambient temperature they experience. I've
seen 344 m/s held out as 'THE' value. Jim Thompson probably has a
special Phoenix value. Root gamma pee over rho. Rho -> less at high
temperatures, so Jim's owl's sound is faster, but not as fast as 440, I
feel sure.
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

 

[Jan Panteltje]

On a sunny day (Wed, 31 Mar 2004 17:17:18 +0100) it happened John Woodgate
<jmw@jmwa.demon.contraspam.yuk> wrote in <LcMXxEDO8uaAFwK2@jmwa.demon.co.uk>:

I read in sci.electronics.design that Genome <Genome@nothere.com> wrote
(in <jVBac.1481$4N3.737@newsfe1-win&gt about 'Change frequency based on
voltage', on Wed, 31 Mar 2004:

I think sound is 440m/s at ground zero.

Try 330. But you get different answers from people in different
countries, depending on what ambient temperature they experience. I've
seen 344 m/s held out as 'THE' value. Jim Thompson probably has a
special Phoenix value. Root gamma pee over rho. Rho -> less at high
temperatures, so Jim's owl's sound is faster, but not as fast as 440, I
feel sure.
I have read about people stopping light in its tracks.

How about stopping sound? Or slowing it down?
Possible?

 

[John Woodgate]

I read in sci.electronics.design that Jan Panteltje
<pNaonSptaemltje@yahoo.com> wrote (in <c4fa33$7gj$1@news.wplus.net&gt
about 'Change frequency based on voltage', on Wed, 31 Mar 2004:

I have read about people stopping light in its tracks.

This is a quantum mechanical phenomenon. I don't think there is any
equivalent in acoustics.

How about stopping sound? Or slowing it down?

Possible?

Slowing down is not much of a problem. It travels fast in most solids,
but I suspect that in the very low density solids called 'aerogels', it
goes much slower.

In the case of gases, uranium hexafluoride is interesting. It's HEAVY,
MAN and it's a gas above 56 C. So the speed of sound in it is much lower
than in air.
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

 

[Jan Panteltje]

On a sunny day (Wed, 31 Mar 2004 21:57:51 +0100) it happened John Woodgate
<jmw@jmwa.demon.contraspam.yuk> wrote in <NRsGygAPDzaAFw7x@jmwa.demon.co.uk>:

I read in sci.electronics.design that Jan Panteltje
pNaonSptaemltje@yahoo.com> wrote (in <c4fa33$7gj$1@news.wplus.net&gt
about 'Change frequency based on voltage', on Wed, 31 Mar 2004:

I have read about people stopping light in its tracks.


This is a quantum mechanical phenomenon. I don't think there is any
equivalent in acoustics.
Indeed.

How about stopping sound? Or slowing it down?

Possible?

Slowing down is not much of a problem. It travels fast in most solids,
but I suspect that in the very low density solids called 'aerogels', it
goes much slower.
Airogel is maily filled with air? At least on earth?

And the solid part of it, would result in faster?

In the case of gases, uranium hexafluoride is interesting. It's HEAVY,
MAN and it's a gas above 56 C. So the speed of sound in it is much lower
than in air.
Bit radio active...not available in spray can yet

 

[Rich Grise]

"John Woodgate" <jmw@jmwa.demon.contraspam.yuk> wrote in message

I read in sci.electronics.design that Jan Panteltje
about 'Change frequency based on voltage', on Wed, 31 Mar 2004:
I have read about people stopping light in its tracks.
This is a quantum mechanical phenomenon. I don't think there is any
equivalent in acoustics.
How about stopping sound? Or slowing it down?
Possible?
Slowing down is not much of a problem. It travels fast in most solids,
but I suspect that in the very low density solids called 'aerogels', it
goes much slower.
In the case of gases, uranium hexafluoride is interesting. It's HEAVY,
MAN and it's a gas above 56 C. So the speed of sound in it is much lower
than in air.

There's an interesting phenomenon that happens with freon when you
inhale a lungful - it's the opposite of helium, i.e. it lowers the
pitch of your voice.

It's clearly related to density, but I never realized that the speed of
sound was a factor - that would change the resonant freq. of a cavity,
after all.

But with freon, you have to rememeber to bend over for awhile to let
it drain out of your lungs.

Cheers!
Rich

 

[John Woodgate]

I read in sci.electronics.design that Rich Grise <null@example.net>
wrote (in <A6Mac.25808$u_2.23738@nwrddc01.gnilink.net&gt about 'Change
frequency based on voltage', on Thu, 1 Apr 2004:

There's an interesting phenomenon that happens with freon when you
inhale a lungful - it's the opposite of helium, i.e. it lowers the

I wouldn't recommend a lungful of uranium hexafluoride! While it would
lower your voice pitch dramatically, it would also silence it
permanently.
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

 

[Tim Shoppa]

John Woodgate <jmw@jmwa.demon.contraspam.yuk> wrote in message news:<d5vCIABBL7aAFw7L@jmwa.demon.co.uk>...

I read in sci.electronics.design that Rich Grise <null@example.net
wrote (in <A6Mac.25808$u_2.23738@nwrddc01.gnilink.net&gt about 'Change
frequency based on voltage', on Thu, 1 Apr 2004:

There's an interesting phenomenon that happens with freon when you
inhale a lungful - it's the opposite of helium, i.e. it lowers the

I wouldn't recommend a lungful of uranium hexafluoride! While it would
lower your voice pitch dramatically, it would also silence it
permanently.

If it's anything like sulfur hexafluroide, then it is quite inert.
(And a very good dielectric!)

Unbinding anything from fluorine takes a lot of work!

Tim.

 

[John Woodgate]

I read in sci.electronics.design that Tim Shoppa <shoppa@trailing-
edge.com> wrote (in <bec993c8.0404011138.511693cd@posting.google.com&gt
about 'Change frequency based on voltage', on Thu, 1 Apr 2004:

If it's anything like sulfur hexafluroide, then it is quite inert.
(And a very good dielectric!)

Unbinding anything from fluorine takes a lot of work!

Think about how much a lungful would weigh, and then think if a lung is
designed to support that.
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

 

[Watson A.Name - \"Watt Su]

"John Woodgate" <jmw@jmwa.demon.contraspam.yuk> wrote in message
news:d5vCIABBL7aAFw7L@jmwa.demon.co.uk...

I read in sci.electronics.design that Rich Grise <null@example.net
wrote (in <A6Mac.25808$u_2.23738@nwrddc01.gnilink.net&gt about 'Change
frequency based on voltage', on Thu, 1 Apr 2004:

There's an interesting phenomenon that happens with freon when you
inhale a lungful - it's the opposite of helium, i.e. it lowers the

I wouldn't recommend a lungful of uranium hexafluoride! While it would
lower your voice pitch dramatically, it would also silence it
permanently.

But you'd glow in the dark!
I like things that glow in the dark..
;-)

They say that the jackrabbits at Hanford glow in the dark!
http://www.pnl.gov/env/Fish_2.html

--
Regards, John Woodgate, OOO - Own Opinions Only.