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From: mike3 on 5 Apr 2010 22:07
Hi.

How would one make a circuit that has a buzzer that, upon a trigger
being tripped, produces a buzz lasting, say 1 second, then stops until
reset? Even with the trigger continuously depressed, the buzz can't
last more than 1 second.
From: SDTPG on 5 Apr 2010 22:26
On Apr 6, 10:07 am, mike3 <mike4...(a)yahoo.com> wrote:
> Hi.
>
> How would one make a circuit that has a buzzer that, upon a trigger
> being tripped, produces a buzz lasting, say 1 second, then stops until
> reset? Even with the trigger continuously depressed, the buzz can't
> last more than 1 second.

Try a monostable
From: Spehro Pefhany on 5 Apr 2010 22:35
On Mon, 5 Apr 2010 19:07:56 -0700 (PDT), the renowned mike3
<mike4ty4(a)yahoo.com> wrote:

>Hi.
>
>How would one make a circuit that has a buzzer that, upon a trigger
>being tripped, produces a buzz lasting, say 1 second, then stops until
>reset? Even with the trigger continuously depressed, the buzz can't
>last more than 1 second.

555 in astable mode. Or use a microcontroller and generate a pleasing
tone as well as timing it.



Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff(a)interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
From: MooseFET on 5 Apr 2010 23:19
On Apr 5, 7:07 pm, mike3 <mike4...(a)yahoo.com> wrote:
> Hi.
>
> How would one make a circuit that has a buzzer that, upon a trigger
> being tripped, produces a buzz lasting, say 1 second, then stops until
> reset? Even with the trigger continuously depressed, the buzz can't
> last more than 1 second.



How about:

Consider CD4060. Look up its datasheet to see how to make an
RC oscillator out of the first section.

Imagine that you make it produce 1024Hz. You want 1024 cycles
and then it stops. If you make it make 512Hz, you want 512
cycles.

Run a diode from the desired Q output to the input of the
oscillator so that when that output goes high is jams the
oscillator high and stops it.

The trigger can be turned into a narrow pulse with a simple RC.
The trigger resets the 4060. The 4060 then counts up to the
desired count and stops.

This has the advantage over LM555 circuits in that it can be
very low power.





From: ehsjr on 6 Apr 2010 01:31
mike3 wrote:
> Hi.
>
> How would one make a circuit that has a buzzer that, upon a trigger
> being tripped, produces a buzz lasting, say 1 second, then stops until
> reset? Even with the trigger continuously depressed, the buzz can't
> last more than 1 second.

Another way, using relays:

Rly1-1 +-----|<--------+
Trigger N/O | |
+ ---+---o->o----+ +----+----[Rly1]-----+
| | | | |
| |> | | |
| __ | |
+---o o------------+ |
| Reset |
| |> | |
| | | |
| +------+ +--[Buz]--+
| | |
| +-----|<-----+ |
| | | |
+---------------+---[Rly2]---+ |
| | |
| Rly1-2 /c |
+--[100R]--+ +---[1K]--| |
| | \e |
|> |<-' | |
| | |
+----[+Cap]----+------+
| |
+----[POT]-----+
^ |
| |
Gnd ----------------------+-------+

Trigger is a momentary normally closed switch and reset
is a momentary normally open switch. Use an NPN darlington
for the transistor, a 100K pot and a 10uF electrolytic.
Adjust the pot to set the duration you want. A larger
cap will allow a longer time for the buzzer to sound.

Ed
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