Time delay with 555

[K.K.]

I want a circuit with a switch (ball or mercury) that will give an
output for t1=1 second to a buzzer every second (t2=1 second),
T=t1+t2, whenever the switch closes (and as long as it remains
closed), but I want this to happen after a 5 seconds delay. My problem
is that I want the 555 to start oscillating provided the switch
remains closed all that 5 seconds delay period and for as long as the
switch is closed. If the switch returns to its open position before
that 5 seconds are passed I want that 5 seconds delay to start over
again the next time the switch closes.
Any help appreciated!

 

[Terry Pinnell]

cs99021@icsd.aegean.gr (K.K.) wrote:

I want a circuit with a switch (ball or mercury) that will give an
output for t1=1 second to a buzzer every second (t2=1 second),
T=t1+t2, whenever the switch closes (and as long as it remains
closed), but I want this to happen after a 5 seconds delay. My problem
is that I want the 555 to start oscillating provided the switch
remains closed all that 5 seconds delay period and for as long as the
switch is closed. If the switch returns to its open position before
that 5 seconds are passed I want that 5 seconds delay to start over
again the next time the switch closes.
Any help appreciated!

If I've understood you correctly, this is a different requirement than
the one you posted here a week ago. That seemed to be asking for a 1s
buzz every 10s, effectively over-ridden by the switch-triggered,
delayed enabler. So can we take it that is no longer needed?

Assuming so, then it seems your signals would look like this:
http://www.terrypin.dial.pipex.com/Images/Timer-KK.gif

Please confirm, or correct.

If that is correct, then it should be simple enought to implement. You
would need two 555s, one a monostable and the other a gated astable.
In addition you'd need a CMOS 4001 Quad NOR IC. One of its gates would
be used to invert the switch signal, S, to give S'. Another would NOR
S' and D to give the required gate. The other two gates would be
unused. The derived gating signal would be used to enable the 555
astable (via its pin 4 reset terminal). Finally, the 1s pulses from
this roughly square wave would drive the buzzer. If its current
requirement was less than 200 mA then the standard 555 could drive it
directly; otherwise a single transistor would provide the extra
current required.

--
Terry Pinnell
Hobbyist, West Sussex, UK

 

[K.K.]

Terry Pinnell <terrypinDELETE@THESEdial.pipex.com> wrote in message news:<0ubsa097k6tans8ikhu6us5ievuor48m9d@4ax.com>...

cs99021@icsd.aegean.gr (K.K.) wrote:

I want a circuit with a switch (ball or mercury) that will give an
output for t1=1 second to a buzzer every second (t2=1 second),
T=t1+t2, whenever the switch closes (and as long as it remains
closed), but I want this to happen after a 5 seconds delay. My problem
is that I want the 555 to start oscillating provided the switch
remains closed all that 5 seconds delay period and for as long as the
switch is closed. If the switch returns to its open position before
that 5 seconds are passed I want that 5 seconds delay to start over
again the next time the switch closes.
Any help appreciated!

If I've understood you correctly, this is a different requirement than
the one you posted here a week ago. That seemed to be asking for a 1s
buzz every 10s, effectively over-ridden by the switch-triggered,
delayed enabler. So can we take it that is no longer needed?

Assuming so, then it seems your signals would look like this:
http://www.terrypin.dial.pipex.com/Images/Timer-KK.gif

Please confirm, or correct.

If that is correct, then it should be simple enought to implement. You
would need two 555s, one a monostable and the other a gated astable.
In addition you'd need a CMOS 4001 Quad NOR IC. One of its gates would
be used to invert the switch signal, S, to give S'. Another would NOR
S' and D to give the required gate. The other two gates would be
unused. The derived gating signal would be used to enable the 555
astable (via its pin 4 reset terminal). Finally, the 1s pulses from
this roughly square wave would drive the buzzer. If its current
requirement was less than 200 mA then the standard 555 could drive it
directly; otherwise a single transistor would provide the extra
current required.

Yes, the signals are correct!
Thank you very much for your help

 

[Terry Pinnell]

cs99021@icsd.aegean.gr (K.K.) wrote:

Terry Pinnell <terrypinDELETE@THESEdial.pipex.com> wrote in message news:<0ubsa097k6tans8ikhu6us5ievuor48m9d@4ax.com>...
cs99021@icsd.aegean.gr (K.K.) wrote:

I want a circuit with a switch (ball or mercury) that will give an
output for t1=1 second to a buzzer every second (t2=1 second),
T=t1+t2, whenever the switch closes (and as long as it remains
closed), but I want this to happen after a 5 seconds delay. My problem
is that I want the 555 to start oscillating provided the switch
remains closed all that 5 seconds delay period and for as long as the
switch is closed. If the switch returns to its open position before
that 5 seconds are passed I want that 5 seconds delay to start over
again the next time the switch closes.
Any help appreciated!

If I've understood you correctly, this is a different requirement than
the one you posted here a week ago. That seemed to be asking for a 1s
buzz every 10s, effectively over-ridden by the switch-triggered,
delayed enabler. So can we take it that is no longer needed?

Assuming so, then it seems your signals would look like this:
http://www.terrypin.dial.pipex.com/Images/Timer-KK.gif

Please confirm, or correct.

If that is correct, then it should be simple enought to implement. You
would need two 555s, one a monostable and the other a gated astable.
In addition you'd need a CMOS 4001 Quad NOR IC. One of its gates would
be used to invert the switch signal, S, to give S'. Another would NOR
S' and D to give the required gate. The other two gates would be
unused. The derived gating signal would be used to enable the 555
astable (via its pin 4 reset terminal). Finally, the 1s pulses from
this roughly square wave would drive the buzzer. If its current
requirement was less than 200 mA then the standard 555 could drive it
directly; otherwise a single transistor would provide the extra
current required.

Yes, the signals are correct!
Thank you very much for your help

OK. Let me know if the earlier description is adequate for you to
build it, or whether you'd like me to post a circuit.

--
Terry Pinnell
Hobbyist, West Sussex, UK

 

[K.K.]

Terry Pinnell <terrypinDELETE@THESEdial.pipex.com> wrote in message news:<asvsa0lf8mdethhqirfdjvoli9lmh1r0e8@4ax.com>...

cs99021@icsd.aegean.gr (K.K.) wrote:

Terry Pinnell <terrypinDELETE@THESEdial.pipex.com> wrote in message news:<0ubsa097k6tans8ikhu6us5ievuor48m9d@4ax.com>...
cs99021@icsd.aegean.gr (K.K.) wrote:

I want a circuit with a switch (ball or mercury) that will give an
output for t1=1 second to a buzzer every second (t2=1 second),
T=t1+t2, whenever the switch closes (and as long as it remains
closed), but I want this to happen after a 5 seconds delay. My problem
is that I want the 555 to start oscillating provided the switch
remains closed all that 5 seconds delay period and for as long as the
switch is closed. If the switch returns to its open position before
that 5 seconds are passed I want that 5 seconds delay to start over
again the next time the switch closes.
Any help appreciated!

If I've understood you correctly, this is a different requirement than
the one you posted here a week ago. That seemed to be asking for a 1s
buzz every 10s, effectively over-ridden by the switch-triggered,
delayed enabler. So can we take it that is no longer needed?

Assuming so, then it seems your signals would look like this:
http://www.terrypin.dial.pipex.com/Images/Timer-KK.gif

Please confirm, or correct.

If that is correct, then it should be simple enought to implement. You
would need two 555s, one a monostable and the other a gated astable.
In addition you'd need a CMOS 4001 Quad NOR IC. One of its gates would
be used to invert the switch signal, S, to give S'. Another would NOR
S' and D to give the required gate. The other two gates would be
unused. The derived gating signal would be used to enable the 555
astable (via its pin 4 reset terminal). Finally, the 1s pulses from
this roughly square wave would drive the buzzer. If its current
requirement was less than 200 mA then the standard 555 could drive it
directly; otherwise a single transistor would provide the extra
current required.

Yes, the signals are correct!
Thank you very much for your help

OK. Let me know if the earlier description is adequate for you to
build it, or whether you'd like me to post a circuit.

What if I want the output of the gated 555 to go high when the output
of 555 monostable is low and the switch is closed(high)? I would be
really greatfull if you could post a circuit for this case!

 

[Terry Pinnell]

cs99021@icsd.aegean.gr (K.K.) wrote:

Terry Pinnell <terrypinDELETE@THESEdial.pipex.com> wrote in message news:<asvsa0lf8mdethhqirfdjvoli9lmh1r0e8@4ax.com>...
cs99021@icsd.aegean.gr (K.K.) wrote:

Terry Pinnell <terrypinDELETE@THESEdial.pipex.com> wrote in message news:<0ubsa097k6tans8ikhu6us5ievuor48m9d@4ax.com>...
cs99021@icsd.aegean.gr (K.K.) wrote:

I want a circuit with a switch (ball or mercury) that will give an
output for t1=1 second to a buzzer every second (t2=1 second),
T=t1+t2, whenever the switch closes (and as long as it remains
closed), but I want this to happen after a 5 seconds delay. My problem
is that I want the 555 to start oscillating provided the switch
remains closed all that 5 seconds delay period and for as long as the
switch is closed. If the switch returns to its open position before
that 5 seconds are passed I want that 5 seconds delay to start over
again the next time the switch closes.
Any help appreciated!

If I've understood you correctly, this is a different requirement than
the one you posted here a week ago. That seemed to be asking for a 1s
buzz every 10s, effectively over-ridden by the switch-triggered,
delayed enabler. So can we take it that is no longer needed?

Assuming so, then it seems your signals would look like this:
http://www.terrypin.dial.pipex.com/Images/Timer-KK.gif

Please confirm, or correct.

If that is correct, then it should be simple enought to implement. You
would need two 555s, one a monostable and the other a gated astable.
In addition you'd need a CMOS 4001 Quad NOR IC. One of its gates would
be used to invert the switch signal, S, to give S'. Another would NOR
S' and D to give the required gate. The other two gates would be
unused. The derived gating signal would be used to enable the 555
astable (via its pin 4 reset terminal). Finally, the 1s pulses from
this roughly square wave would drive the buzzer. If its current
requirement was less than 200 mA then the standard 555 could drive it
directly; otherwise a single transistor would provide the extra
current required.

Yes, the signals are correct!
Thank you very much for your help

OK. Let me know if the earlier description is adequate for you to
build it, or whether you'd like me to post a circuit.

What if I want the output of the gated 555 to go high when the output
of 555 monostable is low and the switch is closed(high)?

That seems to contradict your earlier requirement? Or have you changed
your mind?

But note that I may also have confused you by mistakenly describing
Switch status as 'H = closed'. As you saw from the diagram itself, it
is 'L = closed'. (Assuming you're using a normally-open switch or
button, of course!) That's because, as soon as your switch is closed,
we want it to generate a negative-going pulse in order to trigger the
555 mono.

I would be
really greatfull if you could post a circuit for this case!

I'm reluctant to design a circuit until I know precisely what you
want. So as the next step I suggest you draw a timing diagram, like
mine, defining the specification without ambiguity. BTW, remember to
show the situation for very short periods, i.e. less than the 1s pulse
period of the asatble. Like those of mine on the right. Also, note
that without extra complexity the first cycle of a 555 astable is
always much longer (maybe 30-40%) than all subsequent cycles. Usually
that's of no consequence, and I doubt if it matters a jot in your
case. But it does mean that the first buzz in each group might be
closer to 1.3s than 1.0s.

Also, is it a firm requirement that the circuit 5s timer and astable
must both use the 555 (or a 556 containing two independent 555s)? Or
would you be happy to use CMOS 4001/4011 ICs? Or any other chips for
that matter.

It might also be helpful to describe the *application* for this
circuit.

--
Terry Pinnell
Hobbyist, West Sussex, UK

 

[K.K.]

Terry Pinnell <terrypinDELETE@THESEdial.pipex.com> wrote in message news:<2el0b05pli3evodg56hcqlv9i0126kr240@4ax.com>...

cs99021@icsd.aegean.gr (K.K.) wrote:

Terry Pinnell <terrypinDELETE@THESEdial.pipex.com> wrote in message news:<asvsa0lf8mdethhqirfdjvoli9lmh1r0e8@4ax.com>...
cs99021@icsd.aegean.gr (K.K.) wrote:

Terry Pinnell <terrypinDELETE@THESEdial.pipex.com> wrote in message news:<0ubsa097k6tans8ikhu6us5ievuor48m9d@4ax.com>...
cs99021@icsd.aegean.gr (K.K.) wrote:

I want a circuit with a switch (ball or mercury) that will give an
output for t1=1 second to a buzzer every second (t2=1 second),
T=t1+t2, whenever the switch closes (and as long as it remains
closed), but I want this to happen after a 5 seconds delay. My problem
is that I want the 555 to start oscillating provided the switch
remains closed all that 5 seconds delay period and for as long as the
switch is closed. If the switch returns to its open position before
that 5 seconds are passed I want that 5 seconds delay to start over
again the next time the switch closes.
Any help appreciated!

If I've understood you correctly, this is a different requirement than
the one you posted here a week ago. That seemed to be asking for a 1s
buzz every 10s, effectively over-ridden by the switch-triggered,
delayed enabler. So can we take it that is no longer needed?

Assuming so, then it seems your signals would look like this:
http://www.terrypin.dial.pipex.com/Images/Timer-KK.gif

Please confirm, or correct.

If that is correct, then it should be simple enought to implement. You
would need two 555s, one a monostable and the other a gated astable.
In addition you'd need a CMOS 4001 Quad NOR IC. One of its gates would
be used to invert the switch signal, S, to give S'. Another would NOR
S' and D to give the required gate. The other two gates would be
unused. The derived gating signal would be used to enable the 555
astable (via its pin 4 reset terminal). Finally, the 1s pulses from
this roughly square wave would drive the buzzer. If its current
requirement was less than 200 mA then the standard 555 could drive it
directly; otherwise a single transistor would provide the extra
current required.

Yes, the signals are correct!
Thank you very much for your help

OK. Let me know if the earlier description is adequate for you to
build it, or whether you'd like me to post a circuit.

What if I want the output of the gated 555 to go high when the output
of 555 monostable is low and the switch is closed(high)?

That seems to contradict your earlier requirement? Or have you changed
your mind?

But note that I may also have confused you by mistakenly describing
Switch status as 'H = closed'. As you saw from the diagram itself, it
is 'L = closed'. (Assuming you're using a normally-open switch or
button, of course!) That's because, as soon as your switch is closed,
we want it to generate a negative-going pulse in order to trigger the
555 mono.

I would be
really greatfull if you could post a circuit for this case!

I'm reluctant to design a circuit until I know precisely what you
want. So as the next step I suggest you draw a timing diagram, like
mine, defining the specification without ambiguity. BTW, remember to
show the situation for very short periods, i.e. less than the 1s pulse
period of the asatble. Like those of mine on the right. Also, note
that without extra complexity the first cycle of a 555 astable is
always much longer (maybe 30-40%) than all subsequent cycles. Usually
that's of no consequence, and I doubt if it matters a jot in your
case. But it does mean that the first buzz in each group might be
closer to 1.3s than 1.0s.

Also, is it a firm requirement that the circuit 5s timer and astable
must both use the 555 (or a 556 containing two independent 555s)? Or
would you be happy to use CMOS 4001/4011 ICs? Or any other chips for
that matter.

It might also be helpful to describe the *application* for this
circuit.

Yes, you are right I was confused by the Switch status description!!
So the signals you have desinged are correct from the beggining.
I'm really sorry fot the inconvenience!
And no it is not a firm requirement to use the 555, but I don't know
any other way to build it. Any idea or design is wellcome!

 

[Terry Pinnell]

cs99021@icsd.aegean.gr (K.K.) wrote:

Yes, you are right I was confused by the Switch status description!!
So the signals you have desinged are correct from the beggining.
I'm really sorry fot the inconvenience!
And no it is not a firm requirement to use the 555, but I don't know
any other way to build it. Any idea or design is wellcome!

It's a beautiful day here, so I'm taking a day out for a 12 mile walk.
I'll design your circuit tomorrow.

--
Terry Pinnell
Hobbyist, West Sussex, UK

 

[Terry Pinnell]

Terry Pinnell <terrypinDELETE@THESEdial.pipex.com> wrote:

It's a beautiful day here, so I'm taking a day out for a 12 mile walk.
I'll design your circuit tomorrow.

Here it is, with notes and a timing diagram:
http://www.terrypin.dial.pipex.com/Images/Timer-KK-4001.gif

And also posted to alt.binaries.schematics.electronic.

Several other designs are possible, including one with two 555s, but I
think this is the simplest. As you see, it worked fine on the
breadboard.

--
Terry Pinnell
Hobbyist, West Sussex, UK