Simple delay circuit

Discussion in 'Electronic Basics' started by domwells27@gmail.com, Apr 5, 2006.

  1. Guest

    Hi there

    Im looking to build a delay circuit. Basically i want to be able to
    close a switch which activates a 5 - 10 second delay. Then after the
    delay i want it to turn on an alarm, until the switch is open again.

    Ive been suggested to use a 555 timer, but it looks like after the
    delay the alarm would either oscillate or it would only stay on for x
    amount of seconds.

    Is there any delay circuit out there that will keep the alarm on until
    i open the switch again??

    thanks for any help

    cheers, dom
    , Apr 5, 2006
    #1
  2. Guest

    ive found this circuit:
    http://img327.imageshack.us/img327/5206/r844gs.gif

    Would that do the trick? I assume i attach a 9v battery on pins 8 and 1
    of the 555.

    How would i connect the alarm to pin 3? Also do i need to connect
    anything to pin 2

    thanks for any help

    cheers, dom
    , Apr 5, 2006
    #2
  3. John Fields Guest

    On 5 Apr 2006 06:46:34 -0700, ""
    <> wrote:

    >ive found this circuit:
    >http://img327.imageshack.us/img327/5206/r844gs.gif
    >
    >Would that do the trick? I assume i attach a 9v battery on pins 8 and 1
    >of the 555.


    ---
    That won't work for you since that's just the standard way to
    generate an output pulse. The battery does attach to pin8 (+) and
    pin 1 (-).
    ---

    >How would i connect the alarm to pin 3? Also do i need to connect
    >anything to pin 2


    ---
    Yes to both questions, but since you had to ask, why don't you
    describe in detail what you're trying to do?

    That is, what's the application, what voltage do you want this thing
    and the alarm to run on, how much current does the alarm need, and
    can the switch open instead of closing in order to start the delay?


    --
    John Fields
    Professional Circuit Designer
    John Fields, Apr 5, 2006
    #3
  4. Chris Guest

    wrote:
    > ive found this circuit:
    > http://img327.imageshack.us/img327/5206/r844gs.gif
    >
    > Would that do the trick? I assume i attach a 9v battery on pins 8 and 1
    > of the 555.
    >
    > How would i connect the alarm to pin 3? Also do i need to connect
    > anything to pin 2
    >
    > thanks for any help
    >
    > cheers, dom


    Hi, Dom. One easy way to get additional use out of the 555 is to
    include other things in the circuit -- like your switch, for example,
    and a relay. Assuming you've got a power supply between 5 and 15VDC,
    you can get hold of a relay with a coil of the same voltage that uses
    less than 100mA and you could try something like this (view in fixed
    font or M$ Notepad):

    |
    | SW1
    | VCC-o
    | __--o----o----------o----------o-----o------o---.
    | GND-o | | | | | |
    | | | | | | |
    | 33K.-. | | | | |
    | | | | | | | |
    | | | | | | | |
    | '-' | | | | |
    | | | .---o-----o--. | |
    | o----------)------o2 8 4 | D| C|
    | .001uF | | | | - C|
    | --- | | | ^ C|
    | --- .-----o | | | | RY1
    | | | | | 3o---o---. .---o
    | === | | | | |
    | GND | .-. | | |
    | - R | | | 555 | -----
    | D ^ | | .--o6 | -----
    | | '-' | | | |
    | | | | | | |
    | '-----o---o--o | '---o
    | C | |7 |
    | --- | |
    | --- | |
    | | | |
    | === | |
    | GND | 1 5 |
    | '---o----o---'
    | |
    | ===
    | GND
    |
    (created by AACircuit v1.28.6 beta 04/19/05 www.tech-chat.de)

    The 555 can source or sink current (allegedly up to 200mA, but I'd keep
    it to 50mA -- the output voltage bogs way down when you go over that).
    This trick will ensure an easy, reliable delay-on relay contact for
    your alarm you can wire up just like a switch. Here's how it works:

    When your switch makes contact, the circuit is powered up. The 555 is
    instantly triggered by the 33K resistor and the .001uf cap with a short
    pulse as the cap charges up. The output of the 555 (pin 3) also goes
    to Vcc instantaneously (in relay time). This keeps the relay from
    turning on, because the other end of the coil is also connected to your
    voltage. After the time period you choose by your R and C (68K and
    100uF will give you about 8 seconds), the 555 output will go low. This
    will apply voltage across the relay coil, so it will turn on. You can
    wire the relay contacts up to your alarm just like a switch, so your
    alarm will go on after the 8 seconds. It will stay on until you remove
    the power, because the 555 will only trigger when the trigger pin (2)
    goes low. That won't happen as long as there's power.

    Note that when you turn the Single Pole Double Throw switch (SPDT) off,
    the power connection is grounded. That removes voltage from the relay,
    and discharges the timer cap C through the diode (both Ds can be
    1N4001). If you have a SPST (Single Pole Single Throw) switch, just
    load Vcc down by putting an extra 1K resistor from pin 8 (Vcc) to pin 1
    (GND) to help discharge things when the switch opens.

    I hope this has been of help. If you've already got the 555, and you
    can scrounge a small relay, you should have your alarm working right
    away. If you have any more questions, feel free to ask.

    Good luck with your project
    Chris
    Chris, Apr 5, 2006
    #4
  5. Guest

    Hi there thanks for the info

    I'm looking to make a sonic 'grenade'. Basically i'll have an alarm
    salvaged from a rape alarm running off a 9v battery. I'll put the 'pin'
    out, closing the switch. Then a short delay of around 10 seconds will
    do, before the alram goes off. Preferably i would like the alarm to
    stay on, until the switch is opened again

    Not sure about the operating current though. Oh, and yes the switch
    could be opened or closed i suppose, whichever is easiest

    thanks for the info guys

    cheers, dom
    , Apr 5, 2006
    #5
  6. Chris Guest

    wrote:
    > Hi there thanks for the info
    >
    > I'm looking to make a sonic 'grenade'. Basically i'll have an alarm
    > salvaged from a rape alarm running off a 9v battery. I'll put the 'pin'
    > out, closing the switch. Then a short delay of around 10 seconds will
    > do, before the alram goes off. Preferably i would like the alarm to
    > stay on, until the switch is opened again
    >
    > Not sure about the operating current though. Oh, and yes the switch
    > could be opened or closed i suppose, whichever is easiest
    >
    > thanks for the info guys
    >
    > cheers, dom


    Hi, Dom. I'd guess your piezo alarm probably uses less than 200mA.
    You should be able to use just about any small relay which will operate
    with 9V across the coil.

    If you happen to be around a Radio Shack, try their Catalog #: 275-005
    relay, which states a coil resistance of 500 ohms, and will operate on
    a coil voltage of 9VDC. They're asking $4.29 USD for the thing.
    Together with the 555 circuit above again, all components available at
    Radio Shack), the circuit should use quite a bit less current than the
    piezo alarm itself.

    However, if you're going to be using a 9V transistor battery, you could
    significantly extend the battery life by using a PNP transistor instead
    of the relay, like this:

    |
    | SW1
    | VCC-o
    | __--o----o----------o----------o-----o--------------.
    | GND-o | | | | |
    | | | | | |
    | 33K.-. | | | |
    | | | | | | |
    | | | | | | |
    | '-' | | | |
    | | | .---o-----o--. |
    | o----------)------o2 8 4 | |
    | .001uF | | | | |
    | --- | | | |
    | --- .-----o | | ___ |<
    | | | | | 3o---|___|-| 2N3906
    | === | | | | 1K |\
    | GND | .-. | | |
    | - R | | | 555 | |
    | D ^ | | .--o6 | .---o---.
    | | '-' | | | | |
    | | | | | | | Piezo |
    | '-----o---o--o | |Element|
    | C | |7 | | |
    | --- | | '---o---'
    | --- | | |
    | | | | ===
    | === | | GND
    | GND | 1 5 |
    | '---o----o---'
    | |
    | ===
    | GND
    |
    (created by AACircuit v1.28.6 beta 04/19/05 www.tech-chat.de)

    This will save most of the relay coil current. Note the 2N3906 is also
    available at Radio Shack.

    Good luck with your project
    Chris
    Chris, Apr 5, 2006
    #6
  7. John Fields Guest

    On 5 Apr 2006 11:04:19 -0700, ""
    <> wrote:

    >Hi there thanks for the info
    >
    >I'm looking to make a sonic 'grenade'. Basically i'll have an alarm
    >salvaged from a rape alarm running off a 9v battery. I'll put the 'pin'
    >out, closing the switch. Then a short delay of around 10 seconds will
    >do, before the alram goes off. Preferably i would like the alarm to
    >stay on, until the switch is opened again
    >
    >Not sure about the operating current though. Oh, and yes the switch
    >could be opened or closed i suppose, whichever is easiest
    >
    >thanks for the info guys


    ---
    Here's a simple way to do it if you can reverse the sense of the
    switch. That is, have it open to start the delay. View in Courier:


    +9V----+---------+----------+-------+
    | | |K |
    | | [1N4001] [ALARM]
    | E | |
    | 2N2907 B--[1K]--+-------+
    | C |
    | | |
    [100K] [1K] |
    | | C
    +---------+--------B 2N4401
    |+ | E
    [1200µF] O| |
    | |NC |
    | O| |
    | | |
    GND>---+---------+----------+

    You'll have to change the 2N4401 for something that can handle the
    current if your alarm draws more than about half an amp. the 1N4001
    is in there in case your alarm is inductive or if you want to drive
    a relay with the circuit, in which case you could do this:

    +9V----+---------+----------+-------+
    | | |K | O--->COM
    | | [1N4001] [COIL]- - -|
    | E | | O--> |
    | 2N2907 B--[1K]--+-------+ |
    | C | +-------->NO
    | | |
    [100K] [1K] |
    | | C
    +---------+--------B 2N4401
    |+ | E
    [1200µF] O| |
    | |NC |
    | O| |
    | | |
    GND>---+---------+----------+

    and use the relay to drive the alarm.


    --
    John Fields
    Professional Circuit Designer
    John Fields, Apr 5, 2006
    #7
  8. crazy frog Guest

    ive had the same prob needing a 30second to 60
    for a automation project, so built my own.
    ajustable from 0-60sec to delay switch on
    wile the pc boots so my relays dont flicker.
    no 555 timer in this circuit.
    just a large cap to do the timeing.
    i could send a circuit to youre
    email if you want it.

    <> wrote in message
    news:...
    > Hi there
    >
    > Im looking to build a delay circuit. Basically i want to be able to
    > close a switch which activates a 5 - 10 second delay. Then after the
    > delay i want it to turn on an alarm, until the switch is open again.
    >
    > Ive been suggested to use a 555 timer, but it looks like after the
    > delay the alarm would either oscillate or it would only stay on for x
    > amount of seconds.
    >
    > Is there any delay circuit out there that will keep the alarm on until
    > i open the switch again??
    >
    > thanks for any help
    >
    > cheers, dom
    >
    crazy frog, Apr 6, 2006
    #8
  9. John Fields Guest

    On Thu, 6 Apr 2006 18:57:02 +1000, "crazy frog"
    <> wrote:

    >ive had the same prob needing a 30second to 60
    >for a automation project, so built my own.
    >ajustable from 0-60sec to delay switch on
    >wile the pc boots so my relays dont flicker.
    >no 555 timer in this circuit.
    >just a large cap to do the timeing.
    >i could send a circuit to youre
    >email if you want it.


    ---
    Why not post a copy to alt.binaries.schematics.electronic so we can
    all enjoy it?

    And, BTW, don't top post.

    --
    John Fields
    Professional Circuit Designer
    John Fields, Apr 6, 2006
    #9
  10. crazy frog Guest

    how do you attach the photos?

    i will do it soon.

    "John Fields" <> wrote in message
    news:...
    > On Thu, 6 Apr 2006 18:57:02 +1000, "crazy frog"
    > <> wrote:
    >
    > >ive had the same prob needing a 30second to 60
    > >for a automation project, so built my own.
    > >ajustable from 0-60sec to delay switch on
    > >wile the pc boots so my relays dont flicker.
    > >no 555 timer in this circuit.
    > >just a large cap to do the timeing.
    > >i could send a circuit to youre
    > >email if you want it.

    >
    > ---
    > Why not post a copy to alt.binaries.schematics.electronic so we can
    > all enjoy it?
    >
    > And, BTW, don't top post.
    >
    > --
    > John Fields
    > Professional Circuit Designer
    crazy frog, Apr 8, 2006
    #10
  11. crazy frog Guest

    the circuit is in alt.binaries.schematics.electronics
    now

    "John Fields" <> wrote in message
    news:...
    > On Thu, 6 Apr 2006 18:57:02 +1000, "crazy frog"
    > <> wrote:
    >
    > >ive had the same prob needing a 30second to 60
    > >for a automation project, so built my own.
    > >ajustable from 0-60sec to delay switch on
    > >wile the pc boots so my relays dont flicker.
    > >no 555 timer in this circuit.
    > >just a large cap to do the timeing.
    > >i could send a circuit to youre
    > >email if you want it.

    >
    > ---
    > Why not post a copy to alt.binaries.schematics.electronic so we can
    > all enjoy it?
    >
    > And, BTW, don't top post.
    >
    > --
    > John Fields
    > Professional Circuit Designer
    crazy frog, Apr 8, 2006
    #11
  12. John Fields Guest

    On Sat, 8 Apr 2006 18:21:21 +1000, "crazy frog"
    <> wrote:

    >the circuit is in alt.binaries.schematics.electronics
    >now
    >
    >"John Fields" <> wrote in message
    >news:...
    >> On Thu, 6 Apr 2006 18:57:02 +1000, "crazy frog"
    >> <> wrote:
    >>
    >> >ive had the same prob needing a 30second to 60
    >> >for a automation project, so built my own.
    >> >ajustable from 0-60sec to delay switch on
    >> >wile the pc boots so my relays dont flicker.
    >> >no 555 timer in this circuit.
    >> >just a large cap to do the timeing.
    >> >i could send a circuit to youre
    >> >email if you want it.

    >>
    >> ---
    >> Why not post a copy to alt.binaries.schematics.electronic so we can
    >> all enjoy it?
    >>
    >> And, BTW, don't top post.
    >>
    >> --
    >> John Fields
    >> Professional Circuit Designer


    ---
    That's not a very good circuit. As a matter of fact, it sucks.

    If you want to know why, bottom post for an explanation and I'll
    give you one. Otherwise, forget it unless someone else wants to
    tell you why.


    --
    John Fields
    Professional Circuit Designer
    John Fields, Apr 8, 2006
    #12
  13. Tim Williams Guest

    "John Fields" <> wrote in message
    news:...
    > If you want to know why, bottom post for an explanation and I'll
    > give you one. Otherwise, forget it unless someone else wants to
    > tell you why.


    John, one or two lines at the top of a message is obviously the most
    convienient way to communicate (don't come back with BS of keeping post
    order, you're smart enough to sort out the quote levels and 99% of posts get
    through these days).

    Or better still, a couple lines below a couple lines of quoted text, as
    here. Even you, dear John, have failed this, placing in fact three levels
    of quoted text, totalling a whole 27 lines, above your mere four lines of
    response. I dare say you have no room to complain.

    Tim


    --
    Deep Fryer: a very philosophical monk.
    Website: http://webpages.charter.net/dawill/tmoranwms
    Tim Williams, Apr 8, 2006
    #13
  14. crazy frog Guest

    how can it suck, if it fuckin works.
    i made it work the way i wont it to
    work.
    dick head

    "John Fields" <> wrote in message
    news:...
    > On Sat, 8 Apr 2006 18:21:21 +1000, "crazy frog"
    > <> wrote:
    >
    > >the circuit is in alt.binaries.schematics.electronics
    > >now
    > >
    > >"John Fields" <> wrote in message
    > >news:...
    > >> On Thu, 6 Apr 2006 18:57:02 +1000, "crazy frog"
    > >> <> wrote:
    > >>
    > >> >ive had the same prob needing a 30second to 60
    > >> >for a automation project, so built my own.
    > >> >ajustable from 0-60sec to delay switch on
    > >> >wile the pc boots so my relays dont flicker.
    > >> >no 555 timer in this circuit.
    > >> >just a large cap to do the timeing.
    > >> >i could send a circuit to youre
    > >> >email if you want it.
    > >>
    > >> ---
    > >> Why not post a copy to alt.binaries.schematics.electronic so we can
    > >> all enjoy it?
    > >>
    > >> And, BTW, don't top post.
    > >>
    > >> --
    > >> John Fields
    > >> Professional Circuit Designer

    >
    > ---
    > That's not a very good circuit. As a matter of fact, it sucks.
    >
    > If you want to know why, bottom post for an explanation and I'll
    > give you one. Otherwise, forget it unless someone else wants to
    > tell you why.
    >
    >
    > --
    > John Fields
    > Professional Circuit Designer
    crazy frog, Apr 9, 2006
    #14
  15. crazy frog Guest

    thankyou for backing me up tim

    "Tim Williams" <> wrote in message
    news:pZXZf.735$...
    > "John Fields" <> wrote in message
    > news:...
    > > If you want to know why, bottom post for an explanation and I'll
    > > give you one. Otherwise, forget it unless someone else wants to
    > > tell you why.

    >
    > John, one or two lines at the top of a message is obviously the most
    > convienient way to communicate (don't come back with BS of keeping post
    > order, you're smart enough to sort out the quote levels and 99% of posts

    get
    > through these days).
    >
    > Or better still, a couple lines below a couple lines of quoted text, as
    > here. Even you, dear John, have failed this, placing in fact three levels
    > of quoted text, totalling a whole 27 lines, above your mere four lines of
    > response. I dare say you have no room to complain.
    >
    > Tim
    >
    >
    > --
    > Deep Fryer: a very philosophical monk.
    > Website: http://webpages.charter.net/dawill/tmoranwms
    >
    >
    crazy frog, Apr 9, 2006
    #15
  16. crazy frog wrote:
    >
    > how can it suck,



    Plonk.


    --
    Service to my country? Been there, Done that, and I've got my DD214 to
    prove it.
    Member of DAV #85.

    Michael A. Terrell
    Central Florida
    Michael A. Terrell, Apr 9, 2006
    #16
  17. ehsjr Guest

    crazy frog wrote:
    > how can it suck, if it fuckin works.
    > i made it work the way i wont it to
    > work.
    > dick head


    Wow, I guess you really told him! Now, lets see
    what you accomplished with that reply:
    1) Learned why he said the circuit sucks? Nope.
    2) Learned how to make the circuit better? Nope.
    3) Learned what is "wrong" with the circuit? Nope.
    4) Instilled a desire in others to help you? Nope.
    5) Demonstrated your "design ability" to others? Nope.

    Etc.

    Ouch!

    >
    > "John Fields" <> wrote in message
    > news:...
    >
    >>On Sat, 8 Apr 2006 18:21:21 +1000, "crazy frog"
    >><> wrote:
    >>
    >>
    >>>the circuit is in alt.binaries.schematics.electronics
    >>>now
    >>>
    >>>"John Fields" <> wrote in message
    >>>news:...
    >>>
    >>>>On Thu, 6 Apr 2006 18:57:02 +1000, "crazy frog"
    >>>><> wrote:
    >>>>
    >>>>
    >>>>>ive had the same prob needing a 30second to 60
    >>>>>for a automation project, so built my own.
    >>>>>ajustable from 0-60sec to delay switch on
    >>>>>wile the pc boots so my relays dont flicker.
    >>>>>no 555 timer in this circuit.
    >>>>>just a large cap to do the timeing.
    >>>>>i could send a circuit to youre
    >>>>>email if you want it.
    >>>>
    >>>>---
    >>>>Why not post a copy to alt.binaries.schematics.electronic so we can
    >>>>all enjoy it?
    >>>>
    >>>>And, BTW, don't top post.
    >>>>
    >>>>--
    >>>>John Fields
    >>>>Professional Circuit Designer

    >>
    >>---
    >>That's not a very good circuit. As a matter of fact, it sucks.
    >>
    >>If you want to know why, bottom post for an explanation and I'll
    >>give you one. Otherwise, forget it unless someone else wants to
    >>tell you why.
    >>
    >>
    >>--
    >>John Fields
    >>Professional Circuit Designer

    >
    >
    >
    ehsjr, Apr 9, 2006
    #17
  18. John Fields Guest

    On Sat, 8 Apr 2006 17:15:08 -0500, "Tim Williams"
    <> wrote:

    >"John Fields" <> wrote in message
    >news:...
    >> If you want to know why, bottom post for an explanation and I'll
    >> give you one. Otherwise, forget it unless someone else wants to
    >> tell you why.

    >
    >John, one or two lines at the top of a message is obviously the most
    >convienient way to communicate (don't come back with BS of keeping post
    >order, you're smart enough to sort out the quote levels and 99% of posts get
    >through these days).


    ---
    But, I notice that's not the avenue you chose to take and instead,
    bottom posted like someone with a modicum of intelligence.
    ---

    >Or better still, a couple lines below a couple lines of quoted text, as
    >here.


    ---
    I agree.
    ---

    >Even you, dear John, have failed this, placing in fact three levels
    >of quoted text, totalling a whole 27 lines, above your mere four lines of
    >response. I dare say you have no room to complain.


    ---
    You're complaining about trimming, I'm complaining about bottom
    posting, two entirely different things.

    I almost never top post, but I often leave what might seem to be an
    inordinate amount of quoted material above my reply. Sometimes it's
    because I think the trail is best understood by leaving it intact,
    and sometimes I just can't be bothered to edit it, because ya just
    can't please everybody.

    C'est la vie...


    --
    John Fields
    Professional Circuit Designer
    John Fields, Apr 9, 2006
    #18
  19. John Fields Guest

    On Sun, 9 Apr 2006 10:30:33 +1000, "crazy frog"
    <> wrote:

    >how can it suck, if it fuckin works.


    ---
    I'll tell you if you ask nicely and bottom post.
    ---

    >i made it work the way i wont it to
    >work.


    ---
    The same way you're making the language work for you?
    ---

    >dick head


    ---
    Can't stand being criticized huh?

    I'd have thought you'd be used to it by now...

    --
    John Fields
    Professional Circuit Designer
    John Fields, Apr 9, 2006
    #19
  20. John Fields Guest

    On Sun, 9 Apr 2006 10:36:34 +1000, "crazy frog"
    <> wrote:

    >"Tim Williams" <> wrote in message
    >news:pZXZf.735$...
    >> "John Fields" <> wrote in message
    >> news:...
    >> > If you want to know why, bottom post for an explanation and I'll
    >> > give you one. Otherwise, forget it unless someone else wants to
    >> > tell you why.

    >>
    >> John, one or two lines at the top of a message is obviously the most
    >> convienient way to communicate (don't come back with BS of keeping post
    >> order, you're smart enough to sort out the quote levels and 99% of posts

    >get
    >> through these days).
    >>
    >> Or better still, a couple lines below a couple lines of quoted text, as
    >> here. Even you, dear John, have failed this, placing in fact three levels
    >> of quoted text, totalling a whole 27 lines, above your mere four lines of
    >> response. I dare say you have no room to complain.
    >>
    >> Tim


    >thankyou for backing me up tim


    ---
    I know you have trouble with reading comprehension and a _lot_ of
    trouble with using English properly, but Tim wasn't backing you up.

    He was chiding me for not trimming the material in front of my reply
    to what he considered an acceptable level, not defending your top
    posting.

    Matter of fact, I've arranged your reply, above, the way Tim
    suggests is "better yet". Notice that it's at the bottom of the
    post you're replying to, where it belongs, not at the top, where it
    doesn't.


    --
    John Fields
    Professional Circuit Designer
    John Fields, Apr 9, 2006
    #20

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    phila, Jun 8, 2006, in forum: Misc Electronics
    Replies:
    0
    Views:
    408
    phila
    Jun 8, 2006
  4. JoeSP

    Simple, simple, simple

    JoeSP, Jul 15, 2006, in forum: Home Power and Microgeneration
    Replies:
    9
    Views:
    291
    William P.N. Smith
    Jul 24, 2006
  5. Yoa01

    Simple Analog Delay Circuit

    Yoa01, Oct 29, 2012, in forum: Electronic Projects
    Replies:
    5
    Views:
    590
    Yoa01
    Oct 29, 2012
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