Need circuit to produce 3 modes of audible confirmation

[Jason S]

I need to make a circuit that will produce either one, two or three short
consecutive beeps depending on the input signal it recieves.
For example:

Input 1 = One beep (could mean 'ON').
Input 2 = Two beeps (could mean 'OFF').
Input 3 = Three beeps (could mean 'ERROR')..

This is just an example. The 3rd one is not critical, but would be nice.

I want to be able to add it to practically any circuit which will provide
audible confirmation of the circuit's current operation. I was thinking of
using a PIC to do this, but is last resort (as I know absolutely nothing
about them).

Has anyone got any suggestions?

Thanks.

 

[petrus bitbyter]

I need to make a circuit that will produce either one, two or three short
consecutive beeps depending on the input signal it recieves.
For example:

Input 1 = One beep (could mean 'ON').
Input 2 = Two beeps (could mean 'OFF').
Input 3 = Three beeps (could mean 'ERROR')..

This is just an example. The 3rd one is not critical, but would be nice.

I want to be able to add it to practically any circuit which will provide
audible confirmation of the circuit's current operation. I was thinking
of using a PIC to do this, but is last resort (as I know absolutely
nothing about them).

Has anyone got any suggestions?

Thanks.

A PIC, even the smallest one is the most simple solution... once you can
program it and program it. That's to say you need the skills and the
equipment. If you like to make more of this type of circuits the investment
wil sure pay off. Otherwise, a bunch of 555s may do the job as well.

- One astable (1) for the beep timing (let's say 0.4s on and 0.4s off once
enabled)
- One monostable (1). Triggered by 'ON', enabling the astable (1) for 0.6s.
- One monostable (2). Triggered by 'OFF', enabling the astable (1) for 1.4s.
- One monostable (3). Triggered by 'ERROR', enabling the astable (1) for
2.2s.
- One astable (2) optional to produce a 1kHz beebfrequency once enabled by
astable (1).

The most straightforward way to control astable(1) by the three monostables
is a 3-input OR-gate (or NAND).

petrus bitbyter

 

[petrus bitbyter]

A PIC, even the smallest one is the most simple solution... once you can
program it and program it. That's to say you need the skills and the
equipment. If you like to make more of this type of circuits the
investment wil sure pay off. Otherwise, a bunch of 555s may do the job as
well.

- One astable (1) for the beep timing (let's say 0.4s on and 0.4s off once
enabled)
- One monostable (1). Triggered by 'ON', enabling the astable (1) for
0.6s.
- One monostable (2). Triggered by 'OFF', enabling the astable (1) for
1.4s.
- One monostable (3). Triggered by 'ERROR', enabling the astable (1) for
2.2s.
- One astable (2) optional to produce a 1kHz beebfrequency once enabled by
astable (1).

The most straightforward way to control astable(1) by the three
monostables is a 3-input OR-gate (or NAND).

petrus bitbyter

Oops, forget the NAND as you have no inverted outputs.

petrus bitbyter

 

[Rich Grise]

I need to make a circuit that will produce either one, two or three short
consecutive beeps depending on the input signal it recieves.
For example:

Input 1 = One beep (could mean 'ON').
Input 2 = Two beeps (could mean 'OFF').
Input 3 = Three beeps (could mean 'ERROR')..

This is just an example. The 3rd one is not critical, but would be nice.

I want to be able to add it to practically any circuit which will provide
audible confirmation of the circuit's current operation. I was thinking of
using a PIC to do this, but is last resort (as I know absolutely nothing
about them).

Has anyone got any suggestions?

Well, a PIC would certainly keep the chip count down! But, you have the
investment of maybe $100.00 for the development system, and the time it
takes to learn the programming language, which, if you're a programmer,
shouldn't be hard at all. And the act of selecting which PIC you want
to use is an exercise in itself.

The only other way that springs to my mind is a pot-load of counters
and logic gates and stuff, which sounds like a dandy exercise for the
reader. ;-)

Good Luck!
Rich

 

[petrus bitbyter]

Well, a PIC would certainly keep the chip count down! But, you have the
investment of maybe $100.00 for the development system, and the time it
takes to learn the programming language, which, if you're a programmer,
shouldn't be hard at all. And the act of selecting which PIC you want
to use is an exercise in itself.

The only other way that springs to my mind is a pot-load of counters
and logic gates and stuff, which sounds like a dandy exercise for the
reader. ;-)

Good Luck!
Rich

Well, Rich,

I have to disagree on some points. As for a development system, you can find
all on the net. For free. A programmer (the equipment, not the man) can be
build for much less then $100. Free schematics and plans on the net. The
investment will be in time. Knowing nothing of PICS is not a real problem
but knowing nothing of micros and programming is a pretty high hurdle.

Another way I pointed out in a previous posting. If you use NE556 you can do
with two or three chips (and a pot of resistors and caps

petrus bitbyter

 

[Rich Grise]

I have to disagree on some points. As for a development system, you can
find all on the net. For free. A programmer (the equipment, not the man)
can be build for much less then $100. Free schematics and plans on the
net. The investment will be in time. Knowing nothing of PICS is not a
real problem but knowing nothing of micros and programming is a pretty
high hurdle.

OK, fair enough. I haven't personally attacked that hurdle, because I
haven't really had that much incentive to chase after it.

Another way I pointed out in a previous posting. If you use NE556 you
can do with two or three chips (and a pot of resistors and caps

This is true - I made an SOS light once with about three chips - it was
very much like those amber flashers that you see on the "Under
Construction" signs, but this flashed "SOS" in Morse code

_ _ _ ___ ___ ___ _ _ _ _
___| |_| |_| |_| |_| |_| |_| |_| |_| |_____________| |_ ... etc.

I used "data selector logic" lifted almost directly from Don Lancaster's
TTL Cookbook.

The point of the project was, if you see flashing amber lights, on-off-on-
off, etc, then it means mechanical difficulties. If you see the SOS light,
it means a person in distress, so hurry up and call the ambulance. The
product never got off the ground, but it was fun to design!

And I got paid.

Cheers!
Rich

 

[Ken Smith]

I need to make a circuit that will produce either one, two or three short
consecutive beeps depending on the input signal it recieves.
For example:

Input 1 = One beep (could mean 'ON').
Input 2 = Two beeps (could mean 'OFF').
Input 3 = Three beeps (could mean 'ERROR')..

This is just an example. The 3rd one is not critical, but would be nice.

How about a CMOS 22V10 and a couple of RCs ?

 

[Fred Bloggs]

I need to make a circuit that will produce either one, two or three short

consecutive beeps depending on the input signal it recieves.
For example:

Input 1 = One beep (could mean 'ON').
Input 2 = Two beeps (could mean 'OFF').
Input 3 = Three beeps (could mean 'ERROR')..

This is just an example. The 3rd one is not critical, but would be nice.

I want to be able to add it to practically any circuit which will provide
audible confirmation of the circuit's current operation. I was thinking of
using a PIC to do this, but is last resort (as I know absolutely nothing
about them).

Has anyone got any suggestions?

I get two logic chips, a 555, three diodes, one transistor, two
resistors, the usual 2xR+C 555 astable timing, and a beeper:
View in a fixed-width font such as Courier.

..
.. .------------------------------------------------------.
.. | |
.. | 3x 1N4148 |
.. | --------- |
.. IN 1----------------------+-|>|--+-[100K]-+----|RST OUT|----+
.. | | | | | | |
.. IN 2--------------------+-|-|>|--+ | | 555 | |
.. | | | | | | | |
.. IN 3--------------------|-|-|>|--+ | | ASTABLE | BEEPER
.. | | | | | | | |
.. .-|----------------|-|------+ | | ON TIME | |
.. | | | | | | | =BEEP | |
.. | | | | [100K] | | OFF TIME| ---
.. | | 4017 | | | | | 1/2 BEEP| ///
.. | | -------- | | | | ---------
.. | | | Q0| | | --- \|
.. | | |-- | | | /// 2N3904|---.
.. | '---|CE | | | <| |
.. | | | | | _ 4011 | |
.. | '1'-|CLK Q1|--------| \ --- |
.. | | | | | | o _ /// |
.. | | | | '--|_/ '-| \ |
.. | | | | _ | o--[100K]-+
.. | | Q2|--------| \ .-|_/ |
.. | | | | | o' |
.. | | | '----|_/ |
.. | | | |
.. | _ | Q3|--------------------[100K]-'
.. +-| \ | |
.. | | o|RST . |
.. +-|_/ | |
.. | Q9|
.. | |
.. --------
..
..
..

Any one of the inputs goes high and the 4017 and 555 are taken out of
RESET. The end of each beeper pulse clocks the 4017, outputs of which
are AND'ed with appropriate input line as necessary. When required
number beeps has occurred, transistor RSTs the 555, freezing it in LOW
state, and circuit remains locked up until all inputs are
removed-allowing 4017 to RESET.

 

[Fred Bloggs]

How about a CMOS 22V10 and a couple of RCs ?

That's nonsense!- why do that when you can use the serial port on your PC.

 

[Don Foreman]

This is true - I made an SOS light once with about three chips - it was
very much like those amber flashers that you see on the "Under
Construction" signs, but this flashed "SOS" in Morse code

_ _ _ ___ ___ ___ _ _ _ _
___| |_| |_| |_| |_| |_| |_| |_| |_| |_____________| |_ ... etc.

I used "data selector logic" lifted almost directly from Don Lancaster's
TTL Cookbook.

The point of the project was, if you see flashing amber lights, on-off-on-
off, etc, then it means mechanical difficulties. If you see the SOS light,
it means a person in distress, so hurry up and call the ambulance. The
product never got off the ground, but it was fun to design!

And I got paid.

I made a flashing bike light for my daughter in NYC using a red 1-watt
Luxeon. She said she wanted bright. This sucker is bright!

I thought about having it flash: di di di di dah ..... dah dah di dah
(4Q) to show a little New Yawk attitude -- but I didn't have the
microcontroller ability to do that. Still don't but hope to soon.
Heck, a SOT23-6 10Fxxx PIC would have taken less space than the 555
I used.

 

[Jason S]

I need to make a circuit that will produce either one, two or three short
consecutive beeps depending on the input signal it recieves.
For example:

Input 1 = One beep (could mean 'ON').
Input 2 = Two beeps (could mean 'OFF').
Input 3 = Three beeps (could mean 'ERROR')..

This is just an example. The 3rd one is not critical, but would be nice.

I want to be able to add it to practically any circuit which will provide
audible confirmation of the circuit's current operation. I was thinking
of using a PIC to do this, but is last resort (as I know absolutely
nothing about them).

Has anyone got any suggestions?

I get two logic chips, a 555, three diodes, one transistor, two resistors,
the usual 2xR+C 555 astable timing, and a beeper:
View in a fixed-width font such as Courier.

.
. .------------------------------------------------------.
. | |
. | 3x 1N4148 |
. | --------- |
. IN 1----------------------+-|>|--+-[100K]-+----|RST OUT|----+
. | | | | | | |
. IN 2--------------------+-|-|>|--+ | | 555 | |
. | | | | | | | |
. IN 3--------------------|-|-|>|--+ | | ASTABLE | BEEPER
. | | | | | | | |
. .-|----------------|-|------+ | | ON TIME | |
. | | | | | | | =BEEP | |
. | | | | [100K] | | OFF TIME| ---
. | | 4017 | | | | | 1/2 BEEP| ///
. | | -------- | | | | ---------
. | | | Q0| | | --- \|
. | | |-- | | | /// 2N3904|---.
. | '---|CE | | | <| |
. | | | | | _ 4011 | |
. | '1'-|CLK Q1|--------| \ --- |
. | | | | | | o _ /// |
. | | | | '--|_/ '-| \ |
. | | | | _ | o--[100K]-+
. | | Q2|--------| \ .-|_/ |
. | | | | | o' |
. | | | '----|_/ |
. | | | |
. | _ | Q3|--------------------[100K]-'
. +-| \ | |
. | | o|RST . |
. +-|_/ | |
. | Q9|
. | |
. --------
.
.
.

Any one of the inputs goes high and the 4017 and 555 are taken out of
RESET. The end of each beeper pulse clocks the 4017, outputs of which are
AND'ed with appropriate input line as necessary. When required number
beeps has occurred, transistor RSTs the 555, freezing it in LOW state, and
circuit remains locked up until all inputs are removed-allowing 4017 to
RESET.

Hi Fred, thanks for the schematic - very helpful. Did you come up with that
yourself? Just out of curiosity, have you tested the circuit? I haven't
had a chance to build it yet, but can't wait to see how it works - and
sounds like it will do the job. Most others have mentioned a PIC but I
haven't got the time for that. I will let you know how I went with your
schematic. Thanks again.

Jase.

 

[Jason S]

Thanks to everyone who has made suggestions.

Jase.

 

[Fred Bloggs]

I need to make a circuit that will produce either one, two or three short
consecutive beeps depending on the input signal it recieves.
For example:

Input 1 = One beep (could mean 'ON').
Input 2 = Two beeps (could mean 'OFF').
Input 3 = Three beeps (could mean 'ERROR')..

This is just an example. The 3rd one is not critical, but would be nice.

I want to be able to add it to practically any circuit which will provide
audible confirmation of the circuit's current operation. I was thinking
of using a PIC to do this, but is last resort (as I know absolutely
nothing about them).

Has anyone got any suggestions?

I get two logic chips, a 555, three diodes, one transistor, two resistors,
the usual 2xR+C 555 astable timing, and a beeper:
View in a fixed-width font such as Courier.

.
. .------------------------------------------------------.
. | |
. | 3x 1N4148 |
. | --------- |
. IN 1----------------------+-|>|--+-[100K]-+----|RST OUT|----+
. | | | | | | |
. IN 2--------------------+-|-|>|--+ | | 555 | |
. | | | | | | | |
. IN 3--------------------|-|-|>|--+ | | ASTABLE | BEEPER
. | | | | | | | |
. .-|----------------|-|------+ | | ON TIME | |
. | | | | | | | =BEEP | |
. | | | | [100K] | | OFF TIME| ---
. | | 4017 | | | | | 1/2 BEEP| ///
. | | -------- | | | | ---------
. | | | Q0| | | --- \|
. | | |-- | | | /// 2N3904|---.
. | '---|CE | | | <| |
. | | | | | _ 4011 | |
. | '1'-|CLK Q1|--------| \ --- |
. | | | | | | o _ /// |
. | | | | '--|_/ '-| \ |
. | | | | _ | o--[100K]-+
. | | Q2|--------| \ .-|_/ |
. | | | | | o' |
. | | | '----|_/ |
. | | | |
. | _ | Q3|--------------------[100K]-'
. +-| \ | |
. | | o|RST . |
. +-|_/ | |
. | Q9|
. | |
. --------
.
.
.

Any one of the inputs goes high and the 4017 and 555 are taken out of
RESET. The end of each beeper pulse clocks the 4017, outputs of which are
AND'ed with appropriate input line as necessary. When required number
beeps has occurred, transistor RSTs the 555, freezing it in LOW state, and
circuit remains locked up until all inputs are removed-allowing 4017 to
RESET.

Hi Fred, thanks for the schematic - very helpful. Did you come up with that
yourself? Just out of curiosity, have you tested the circuit? I haven't
had a chance to build it yet, but can't wait to see how it works - and
sounds like it will do the job. Most others have mentioned a PIC but I
haven't got the time for that. I will let you know how I went with your
schematic. Thanks again.

Jase.

No need to breadboard, these parts are too familiar. I did a
confirmation check in mixed-mode SPICE and it works as expected. What
kind of beeper are you working with?- there are several types- some are
self-oscillating so that all the 555 has to do is apply voltage to it,
others are just transducers and you have to supply the oscillatory
input. In the second case you will have to make a 555 oscillator at
2-3KHz to drive it, and use the 555 on the schematic to drive its RST
input- gating it on and off. I suppose a beep duration of 500ms ON and
250ms OFF should be about right- and that would be something like this:
View in a fixed-width font such as Courier.

..
..
.. TO <---------------------.
.. 4017 |
.. /CE |
.. 5V |
.. | |
.. .-----+--[270K]---+ |
.. | | | |
.. | [270K] +------------+ |
.. | | | VCC | |
.. | | | | |
.. FROM >----|-----|----|RST OUT|-+-> TO BEEPER
.. LOGIC | | | | .
.. | +----|THRESH | |
.. | | | | |
.. | +----|TRIG DIS|-. |
.. | + | | | | |
.. | === | GND | | |
.. | 1U| +------------+ | |
.. | | | | |
.. | '-----------+ | |
.. | | | |
.. | GND | |
.. | | |
.. '-------------------------' |
.. |
.. |
.. |
.. .---------------------------------'
.. |
.. |
.. |
.. | 5V
.. | |
.. .----|---+--[27K]----+
.. | | | |
.. | | [270K] +------------+
.. | | | | VCC |
.. | | | | |
.. | '---|----|RST OUT|--------.
.. | | | | |
.. | +----|THRESH | |
.. | | | | |
. | +----|TRIG DIS|-. PIEZO
. | | | | | |
. | === | GND | | |
. | 1n| +------------+ | |
. | | | | |
. | '-----------+-------|------'
. | | |
. | GND |
. | |
. '----------------------------

 

[Ken Smith]

In my never ending battle to save parts I suggest:

Modified version:

.
.
. TO <-+-------------------.
. 4017 | |
. /CE | |
. | 5V |
. | | |
. | | |
. | | |
. [270K] +------------+ |
. | | VCC | |
. | | | |
. FROM >----------|----|RST OUT|-+-> TO BEEPER
. LOGIC | | |
. +----|THRESH |
. | | |
. +----|TRIG DIS|--------
. + | | | |
. === | GND | |
. 1U| +------------+ |
. | | |
. '-----------+ |
. | |
. GND |
. |
. |
. |
. |
. |
. .---------------------------------'
. |
. | --------------------------
. | | |
. | | 5V |
. | | | |
. | | | |
. | | | |
. | [270K] +------------+ |
. | | | VCC | |
. | | | | |
. '---+ |RST OUT|--------+
. | | | |
. +----|THRESH | |
. | | | |
. +----|TRIG DIS|- PIEZO
. | | | |
. === | GND | |
. 1n| +------------+ |
. | | |
. '-----------+--------------'
. |
. GND
.
.
.

BTW: I'd use a ceramic for the 1uF. There is a lot less risk of putting
it in backwards that way.

 

[Fred Bloggs]

In my never ending battle to save parts I suggest:

Modified version:

.
.
. TO <-+-------------------.
. 4017 | |
. /CE | |
. | 5V |
. | | |
. | | |
. | | |
. [270K] +------------+ |
. | | VCC | |
. | | | |
. FROM >----------|----|RST OUT|-+-> TO BEEPER
. LOGIC | | |
. +----|THRESH |
. | | |
. +----|TRIG DIS|--------
. + | | | |
. === | GND | |
. 1U| +------------+ |
. | | |
. '-----------+ |
. | |
. GND |
. |
. |
. |
. |
. |
. .---------------------------------'
. |
. | --------------------------
. | | |
. | | 5V |
. | | | |
. | | | |
. | | | |
. | [270K] +------------+ |
. | | | VCC | |
. | | | | |
. '---+ |RST OUT|--------+
. | | | |
. +----|THRESH | |
. | | | |
. +----|TRIG DIS|- PIEZO
. | | | |
. === | GND | |
. 1n| +------------+ |
. | | |
. '-----------+--------------'
. |
. GND
.
.
.

BTW: I'd use a ceramic for the 1uF. There is a lot less risk of putting
it in backwards that way.

And here I opened your post on the outside chance you would tell me
something new. I don't really care for the 50-50 beep alert as it lacks
sufficient enthusiasm in my estimation, so I will splurge and use the
additional resistor thank you very much. But here's something novel- a
diode used to practically eliminate the extra long first pulse effect.
SPICE says it works, and I don't see why the real world should disagree
as long as the output is effectively unloaded. The price you pay is loss
of the ratiometric switching thresholds but that is not required in the
majority of applications. You can do whatever you want with the piezo
astable- it's neither here nor there.
View in a fixed-width font such as Courier.

..
..
.. TO <-----------------------------.
.. 4017 |
.. /CE |
.. 5V |
.. | |
.. .---[330K]--+ |
.. | | |
.. +-----------|---------. |
.. | | | |
.. [120K] +------------+ | |
.. | | VCC | | |
.. | | | | |
.. FROM >----------|RST OUT|---------+
.. LOGIC | | | | |
.. CKT +----|THRESH | | |
.. | | | | |
.. +----|TRIG DIS|---' |
.. | | | |
.. | | | 1N4148 |
.. | | CONT|--|>|----+
.. | | | |
.. + | | | |
.. === | GND | |
.. 1U| +------------+ |
.. | | |
.. '-----------+ |
.. | |
.. GND |
.. \|/
..
.. to RST of
.. piezo astable
..
..

 

[Ken Smith]

This will work too:

.
.
. TO <-----------------------------.
. 4017 |
. /CE |
. 5V |
. | |
. .---[330K]--+ |
. | | |
. +-----------|---------. |
. | | | |
. [120K] +------------+ | |
. | | VCC | | |
. | | | | |
. FROM >+---------|RST OUT|---------+
. LOGIC | | | | | |
. CKT --- +----|THRESH | | |
. --- | | | | |
. 0.5 | +----|TRIG DIS|---' |
. ----+ | | |
. | | | |
. | | CONT| |
. | | | |
. + | | | |
. === | GND | |
. 1U| +------------+ |
. | | |
. '-----------+ |
. | |
. GND |
. \|/
.
. to RST of
. piezo astable

When RST goes high, the 0.5u puts the trigger at Vcc/3.

BTW: You can make pulsing beep with just one 555. Unfortunately, there
is no easy way to do the CD4017 running from it. It looks like this:



100K 10K 100K 10K 1u
Vcc -/\/\/-+-/\/\-+-/\/\-+---+--/\/\--!!--+---- Output
! ! ! ! !
! 10u --- 0.1--- ! !
! --- --- ! !
! ! ! +- !
! GND GND ! ! !
! ! ! !

 

[Jason S]

Hi Fred,

To answer your question, I will be using a self-driven piezo buzzer which
DOES NOT oscillate (I thought that was what I was supposed to use?), so the
555 will apply power to it when a beep is required (via the usual
resistor/transistor/diode arrangement).

I did a breadboard test of your original schematic this morning, and it
seems to be operating PARTIALLY o.k - Not sure if I did anything wrong -
there's wires everywhere! arrghhh!. There's bit of a problem that I have
encountered....

Problem # 1 :
The 555's outpin pin is high if there are no inputs connected (standby) -
isn't it supposed to be low? As soon as I connect an output, it works o.k
but as soon as the input is disconnected (when the 4017 resets), the 555's
output pin goes high again and stays high (causing the buzzer to sound
continuously!). Not sure what to do here Fred~! I used a logic probe and
the NAND gate that connects to the RST pin of the 4017 intermittently gives
half high half low, and found that the circuit then doesn't 'reset'. Funny
how it's only sometimes.

Problem # 2:
Also if there is already an input connected BEFORE I turn the power on to
the circuit, buzzer will beep 7, 8 or 9 times before it stops!
i.e. Input 1 = 7 beeps. Input 2 = 8 beeps. Input 3 = 9 beeps.
However, the 4017 seems to be going through only 1 cycle (which is good),
because according to the logic probe, each of the outputs go 'high' only
once. Weird.

Let me confirm the following:
1) All gates used are of NAND type (4011). Note that your text mentioned
'AND'd'!).
2) The 4017's CLK/Clock pin is connected to the positive rail at all times.
???
3) Output from the 555 is connected to the CE/Clock Enable pin of the 4017.
4) The inputs - finding that circuit doesn't work properly if any unused
input is 'floating' (i.e. not connected to ground). Are the diodes in the
correct spot?
5) What's the deal of not having a square wave for the 555 output? Does it
matter? My output seems pretty square.

Thanks again,

Jason.

I need to make a circuit that will produce either one, two or three
short consecutive beeps depending on the input signal it recieves.
For example:

Input 1 = One beep (could mean 'ON').
Input 2 = Two beeps (could mean 'OFF').
Input 3 = Three beeps (could mean 'ERROR')..

This is just an example. The 3rd one is not critical, but would be nice.

I want to be able to add it to practically any circuit which will
provide audible confirmation of the circuit's current operation. I was
thinking of using a PIC to do this, but is last resort (as I know
absolutely nothing about them).

Has anyone got any suggestions?

I get two logic chips, a 555, three diodes, one transistor, two
resistors, the usual 2xR+C 555 astable timing, and a beeper:
View in a fixed-width font such as Courier.

.
. .------------------------------------------------------.
. | |
. | 3x 1N4148 |
. | --------- |
. IN 1----------------------+-|>|--+-[100K]-+----|RST OUT|----+
. | | | | | | |
. IN 2--------------------+-|-|>|--+ | | 555 | |
. | | | | | | | |
. IN 3--------------------|-|-|>|--+ | | ASTABLE | BEEPER
. | | | | | | | |
. .-|----------------|-|------+ | | ON TIME | |
. | | | | | | | =BEEP | |
. | | | | [100K] | | OFF TIME| ---
. | | 4017 | | | | | 1/2 BEEP| ///
. | | -------- | | | | ---------
. | | | Q0| | | --- \|
. | | |-- | | | /// 2N3904|---.
. | '---|CE | | | <| |
. | | | | | _ 4011 | |
. | '1'-|CLK Q1|--------| \ --- |
. | | | | | | o _ /// |
. | | | | '--|_/ '-| \ |
. | | | | _ | o--[100K]-+
. | | Q2|--------| \ .-|_/ |
. | | | | | o' |
. | | | '----|_/ |
. | | | |
. | _ | Q3|--------------------[100K]-'
. +-| \ | |
. | | o|RST . |
. +-|_/ | |
. | Q9|
. | |
. --------
.
.
.

Any one of the inputs goes high and the 4017 and 555 are taken out of
RESET. The end of each beeper pulse clocks the 4017, outputs of which are
AND'ed with appropriate input line as necessary. When required number
beeps has occurred, transistor RSTs the 555, freezing it in LOW state,
and circuit remains locked up until all inputs are removed-allowing 4017
to RESET.

Hi Fred, thanks for the schematic - very helpful. Did you come up with
that yourself? Just out of curiosity, have you tested the circuit? I
haven't had a chance to build it yet, but can't wait to see how it
works - and sounds like it will do the job. Most others have mentioned a
PIC but I haven't got the time for that. I will let you know how I went
with your schematic. Thanks again.

Jase.

No need to breadboard, these parts are too familiar. I did a confirmation
check in mixed-mode SPICE and it works as expected. What kind of beeper
are you working with?- there are several types- some are self-oscillating
so that all the 555 has to do is apply voltage to it, others are just
transducers and you have to supply the oscillatory input. In the second
case you will have to make a 555 oscillator at 2-3KHz to drive it, and use
the 555 on the schematic to drive its RST input- gating it on and off. I
suppose a beep duration of 500ms ON and 250ms OFF should be about right-
and that would be something like this:
View in a fixed-width font such as Courier.

.
.
. TO <---------------------.
. 4017 |
. /CE |
. 5V |
. | |
. .-----+--[270K]---+ |
. | | | |
. | [270K] +------------+ |
. | | | VCC | |
. | | | | |
. FROM >----|-----|----|RST OUT|-+-> TO BEEPER
. LOGIC | | | | .
. | +----|THRESH | |
. | | | | |
. | +----|TRIG DIS|-. |
. | + | | | | |
. | === | GND | | |
. | 1U| +------------+ | |
. | | | | |
. | '-----------+ | |
. | | | |
. | GND | |
. | | |
. '-------------------------' |
. |
. |
. |
. .---------------------------------'
. |
. |
. |
. | 5V
. | |
. .----|---+--[27K]----+
. | | | |
. | | [270K] +------------+
. | | | | VCC |
. | | | | |
. | '---|----|RST OUT|--------.
. | | | | |
. | +----|THRESH | |
. | | | | |
. | +----|TRIG DIS|-. PIEZO
. | | | | | |
. | === | GND | | |
. | 1n| +------------+ | |
. | | | | |
. | '-----------+-------|------'
. | | |
. | GND |
. | |
. '----------------------------
.
.

 

[Fred Bloggs]

Hi Fred,

To answer your question, I will be using a self-driven piezo buzzer
which DOES NOT oscillate (I thought that was what I was supposed to
use?), so the 555 will apply power to it when a beep is required (via
the usual resistor/transistor/diode arrangement).

I did a breadboard test of your original schematic this morning, and
it seems to be operating PARTIALLY o.k - Not sure if I did anything
wrong - there's wires everywhere! arrghhh!. There's bit of a problem
that I have encountered....

Problem # 1 : The 555's outpin pin is high if there are no inputs
connected (standby) - isn't it supposed to be low? As soon as I
connect an output, it works o.k but as soon as the input is
disconnected (when the 4017 resets), the 555's output pin goes high
again and stays high (causing the buzzer to sound continuously!).
Not sure what to do here Fred~! I used a logic probe and the NAND
gate that connects to the RST pin of the 4017 intermittently gives
half high half low, and found that the circuit then doesn't 'reset'.
Funny how it's only sometimes.

You are using the bipolar 555 and the typical RST pin current is listed
as 0.1mA, for which the 100K resistors are much too high. If you want to
keep the signal input impedance of the circuit high then you will have
to use the circuit attached below or go to a CMOS 555.

Problem # 2: Also if there is already an input connected BEFORE I
turn the power on to the circuit, buzzer will beep 7, 8 or 9 times
before it stops! i.e. Input 1 = 7 beeps. Input 2 = 8 beeps. Input 3
= 9 beeps. However, the 4017 seems to be going through only 1 cycle
(which is good), because according to the logic probe, each of the
outputs go 'high' only once. Weird.

If live inputs while the circuit is unpowered are a real possibility
then you should put a 10K in series with the input of the NAND driving
the 4017 RST input, and you can add a C+R from VCC to one input of that
NAND for a power on RST if you don't like the beeps.

Let me confirm the following: 1) All gates used are of NAND type
(4011). Note that your text mentioned 'AND'd'!).
Yep-

2) The 4017's CLK/Clock pin is connected to the positive rail at all
times. ???
Yep-

3) Output from the 555 is connected to the CE/Clock Enable pin of
the 4017.
Yep-

4) The inputs - finding that circuit doesn't work properly if any
unused input is 'floating' (i.e. not connected to ground). Are the
diodes in the correct spot?

Either go with a CMOS 555 or use circuit below.

5) What's the deal of not having a square wave for the 555 output?
Does it matter? My output seems pretty square.

It's only personal preference- if you're satisfied with the sound then
go with it.

As I said- either go with CMOS 555 and original circuit, or keep your
bipolar 555 and mod the circuit like shown below. You add a pull-up
resistor from 555 RST to Vcc, the NAND driver for the 4017 RST also
drives the transistor base OR circuit through a 10K and a 10K replaces
the 100K in the other drivers of the base circuit. A power on RC has
been added to RST the 4017 at turn-on. The operation is basically the
same except that now when an IN goes high, it indirectly causes 555 RST
high through the NAND+ transistor combination, instead of directly. The
555 is now RST after required number of beeps OR when the inputs are
removed.
View in a fixed-width font such as Courier.

..
.. 5V
.. 1U |
.. GND--||--+----[100K]-------+
.. | |
.. .------------------------------------------------------.
.. | | _ | |
.. | 3x 1N4148 '---| \ [10K] |
.. | | o-. | --------- |
.. IN 1------[10K]--+-|>|--+---|_/ | +----|RST OUT|----+
.. | | | | | | | |
.. IN 2------[10K]+-|-|>|--+ | | | 555 | |
.. | | | | | | | | |
.. IN 3-----------|-|-|>|--+ | | | ASTABLE | BEEPER
.. | | | | | | | | |
.. | | | [100K] | | | ON TIME | |
.. | | | | | | | =BEEP | |
.. | | | GND | | | OFF TIME| GND
.. | | | | | | 1/2 BEEP|
.. | | | | | ---------
.. | | | | |
.. | | | | |
.. | | '--------. | |
.. | '--------. | | |
.. | | | | |
.. .---------------------------+-[10K]--------.
.. | | | | | |
.. | | --4017-- | | | |
.. | | | Q0| | | \| |
.. | | |-- | | | 2N3904|---+
.. | '---|CE | | | <| |
.. | | | | | _ 4011 | |
.. | '1'-|CLK Q1|--------| \ GND |
.. | | | | | | o _ |
.. | | | | '--|_/ '-| \ |
.. | | | | _ | o--[10K]--+
.. | | Q2|--------| \ .-|_/ |
.. | | | | | o' |
.. | | | '----|_/ |
.. | | | |
.. | | Q3|--------------------[10K]--'
.. | | |
.. '-----|RST . |
.. | |
.. | Q9|
.. | |
.. --------

 

[Fred Bloggs]

That would be 10K in series with each IN line:
View in a fixed-width font such as Courier.

..
.. 5V
.. 1U |
.. GND--||--+----[100K]-------+
.. | |
.. .------------------------------------------------------.
.. | | _ | |
.. | 3x 1N4148 '---| \ [10K] |
.. | | o-. | --------- |
.. IN 1-----[10K]---+-|>|--+---|_/ | +----|RST OUT|----+
.. | | | | | | | |
.. IN 2-----[10K]-+-|-|>|--+ | | | 555 | |
.. | | | | | | | | |
.. IN 3-----[10K]-|-|-|>|--+ | | | ASTABLE | BEEPER
.. | | | | | | | | |
.. | | | [100K] | | | ON TIME | |
.. | | | | | | | =BEEP | |
.. | | | GND | | | OFF TIME| GND
.. | | | | | | 1/2 BEEP|
.. | | | | | ---------
.. | | | | |
.. | | | | |
.. | | '--------. | |
.. | '--------. | | |
.. | | | | |
.. .---------------------------+-[10K]--------.
.. | | | | | |
.. | | --4017-- | | | |
.. | | | Q0| | | \| |
.. | | |-- | | | 2N3904|---+
.. | '---|CE | | | <| |
.. | | | | | _ 4011 | |
.. | '1'-|CLK Q1|--------| \ GND |
.. | | | | | | o _ |
.. | | | | '--|_/ '-| \ |
.. | | | | _ | o--[10K]--+
.. | | Q2|--------| \ .-|_/ |
.. | | | | | o' |
.. | | | '----|_/ |
.. | | | |
.. | | Q3|--------------------[10K]--'
.. | | |
.. '-----|RST . |
.. | |
.. | Q9|
.. | |
.. --------

 

[Fred Bloggs]

4) The inputs - finding that circuit doesn't work properly if any unused
input is 'floating' (i.e. not connected to ground). Are the diodes in the
correct spot?

You can't let the inputs 1 & 2 "float" since these connect to the logic
NANDs on the output of counter, the logic requires well-defined voltage
levels , either H or L, voltages in between cause them to act up. You
have to put pulldowns to GND there- say 1M ohms- put 1M's right at the
input to the circuit on all IN's for consistency. Where are your inputs
coming from anyway? The diodes are a logic OR and they are in the
correct spot.