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Basic Circuit without Stamp - sound a siren for 5 seconds when button pressed? — Parallax Forums

Basic Circuit without Stamp - sound a siren for 5 seconds when button pressed?

MorrolanMorrolan Posts: 98
edited 2008-03-27 14:10 in General Discussion
Hi guys,
I've suddenly found a need to create a simple circuit without a stamp, but my brain has gone on holiday! I require a circuit that involves a button and a buzzer. Once the button is pressed, (momentary push, no need to hold it) I want a siren to sound for 5 seconds. My electronics is so rusty, and everything I've re-taught myself lately has revolved around using a stamp of some kind to control things even a 1st year Electronics student should be able to do!

Please can someone just point me in the right direction, I should then be able to figure something out...

Many Thanks,
Morrolan

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Comments

  • Bruce BatesBruce Bates Posts: 3,045
    edited 2008-03-05 10:19
    Morrolan -

    Try a 555 timer with a couple of appropriate resistors and caps.

    Regards,

    Bruce Bates

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  • T&E EngineerT&E Engineer Posts: 1,396
    edited 2008-03-05 11:08
    I would also consider the Parallax SoundPal. It uses it's own uProcessor so it can play independently from the Basic Stamp 2. SX chips, propeller, etc. It's pretty small and is a complete and simple interfacing solution for you. It offers alot of programmable tones that's fairly loud too.

    http://www.parallax.com/Store/Accessories/Sound/tabid/164/CategoryID/38/List/0/Level/a/ProductID/482/Default.aspx?SortField=ProductName%2cProductName
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2008-03-06 10:03
    You might need a double 555 timer to cascade one trigger to another. 5 seconds is a bit long. 555 timers can be quite loud as they can use much higher voltage and output quite a few milliamps.

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  • Twisted PairTwisted Pair Posts: 177
    edited 2008-03-07 02:30
    Morrolan,

    Try this.

    Twisted Pair....


    Post Edited (Twisted Pair) : 3/7/2008 3:18:17 AM GMT
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  • Twisted PairTwisted Pair Posts: 177
    edited 2008-03-23 19:17
    Morrolan,

    Did you get what you needed ?

    Twisted Pair....
  • Junk_BotJunk_Bot Posts: 15
    edited 2008-03-25 15:38
    All these solutions seem to complicated to me.confused.gif

    If the buzzer only needs·to sound for approximately 5 seconds just wire a

    capacitor up in parralel with a buzzer as shown in the attachment.

    When the pushbutton is pushed it will charge the capacitor and sound the buzzer.

    However, when the pushbutton is released all the current will flow through the buzzer.

    The duration of the sound will depend on the size of the capacitor.

    Note: It may be best to try this on a breadboard first. Experiment with different capacitor sizes.

    Other note: This circuit will only work with buzzers that don't require frequency input eg. buzzers like

    Radioshack Catalog #: 273-080 or Radioshack Catalog #: 273-057 these buzzers should be nice and loud.

    Final note: Make sure you don't hook the buzzer up backwords.

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  • Mike GreenMike Green Posts: 23,101
    edited 2008-03-25 19:00
    It's not a bad idea, but most capacitors won't store enough current to keep a buzzer going for 5 seconds. It all depends on the current draw of the buzzer and the capacitance of the capacitor.
  • Junk_BotJunk_Bot Posts: 15
    edited 2008-03-27 14:10
    Accutally I've seen this circuit used before, and it worked quite well.
    However in the diagram the capaitor is a 1000uf capacitor.
    That was an error, and you do need something much bigger.

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