555 monostable buzzer

Discussion in 'The Projects Forum' started by scootnation, Feb 9, 2011.

  1. scootnation

    Thread Starter New Member

    Feb 9, 2011
    hi all, i am new to the world of electronics so you will have to bear with me. I simply want to make a compact circuit that creates a beep when a circuit is made and then repeats at a set interval until the circuit is broken. The problem is i want use a small 3v battery like a CR2032 or similar (i could possibly use 2) but i dont know what voltage a 555 requires. would i be better using a ICM7555? i understand the monostable circuit but am struggling with the maths involving the beep duration and interval. does the voltage change the math? I was wondering if someone could tell me what components to use, resistors, capacitor, buzzer? i want a 2 second beep repeated every 20 seconds.
    All help would be appreciated.
  2. Wendy


    Mar 24, 2008
    Several minor issues, a monostable triggers once, then doesn't repeat. It creates a single pulse, which is not what you are wanting.

    Your keywords are "astable" or "oscillator". Astable generally generates slow digital pulses, which is much closer to what you seem to be wanting.

    I have generated a set of tutorials you might find useful.

    Bill's Index

    The 555 Projects

    LEDs, 555s, Flashers, and Light Chasers

    From what you are describing you probably want a simple device like a sonalert, which is a solid state noisemaker, a modern buzzer. It can be driven with a simple 555 or CMOS 555.

    Your battery voltage will only power a CMOS 555, since a 555 has a minimum spec of 4.5VDC, and CMOS is generally 2VDC. The downside of a CMOS 555 is they have a very weak drive at those voltage, so amplification is required just for the digital signal (on/off).

    Show us what you have sketched up, schematics are the language of electronics, and we can help you polish your design. It is a common theme here at AAC, it is one of the things we do.

    Welcome to AAC!