Help with Oscillator

Discussion in 'General Electronics Chat' started by redlight000, Mar 12, 2010.

  1. redlight000

    Thread Starter Member

    Feb 26, 2010
    66
    2
    Hi all,

    I would appricate some help on how to build with a Timer chip if applicable a slow rising buzz, then rising up into the inaudio bandwidth, say 13khz, the starting FREQ, Im not sure of, but its the slow build up of the sound Im after taking around 17seconds to complete.. then starts again say after 7seconds.. any any hints tips clues/ links.. would be most helpful..
    Sorry I forgot to mention would like a push button switch to start the sound off..

    thanks very much if ANYone can solve this mind boggling thing Im after..

    from
    redlight000
    :eek:
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    redlight000 likes this.
  3. redlight000

    Thread Starter Member

    Feb 26, 2010
    66
    2
    Hi Beenthere,

    thanks for the reply, can you suggest which siren to go for? as there's so many there..

    cheers
    from
    Redlight000
     
  4. Wendy

    Moderator

    Mar 24, 2008
    20,766
    2,536
    I think what you're after is a VCO (Voltage Controlled Oscillator) with a ramp input. The ramp produces a slow sawtooth, that when feed into the VCO would produce something like what you want.
     
    redlight000 likes this.
  5. redlight000

    Thread Starter Member

    Feb 26, 2010
    66
    2
    Hi Bill,
    I dont know where to look for a VCO? and ramp input!!! have you a basic Link? that might help?

    many thanks
    redlight000
    :eek:
     
  6. Wendy

    Moderator

    Mar 24, 2008
    20,766
    2,536
    I don't have time to design it, but I can point you in the general direction. It may not be satisfactory, you'll just have to protoboard it and see.

    [​IMG]
     
    redlight000 likes this.
  7. redlight000

    Thread Starter Member

    Feb 26, 2010
    66
    2
    Hi Bill,

    many thanks for the starting Point.. at least I've got some idea now!!!:D
     
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