Connect with us

Buzzer Help

Discussion in 'General Electronics Discussion' started by Rajinder, Aug 1, 2016.

  1. Rajinder

    Rajinder

    408
    7
    Jan 30, 2016
    Hi,
    I have attached a copy of the voltge seen on a piezo buzzer. I need to ckamp this to 3V3 and then detect the edges of the waverform at 1.17 secs, feed this into a microcontroller and measure the time between pulses.

    I was thinking of clamping the wavefor which is 30V by using a suitable resistor and zener diode at 3V3 or around that figure. This will remove the negative going part of the waveform. Then feed this into a differentiator to detect the positive edges and feet into a microcontroller I/O pin.

    If the piezo was say operating at 20mA (for example), to calculate the series resistor with the zener is it simply a case of 30-3v3/20mA. Then ensuring power requirements can be satisfied i.e. wattage of resistor.

    would this be then suitable to connect to the differentiator circuit? or would i need some further signal cleaning after the differentiator stage?

    any help would be appreciated.

    Best regards,
    raj
     

    Attached Files:

  2. Arouse1973

    Arouse1973 Adam

    5,164
    1,078
    Dec 18, 2013
    It must be the water draining away some of the magnetic field :)
     
  3. Alec_t

    Alec_t

    2,691
    712
    Jul 7, 2015
    Not unless you want 20mA flowing through the zener. The buzzer current is irrelevant. Make R=(30-3.3)/Izener. A zener current of just a few mA should be enough.
     
  4. Rajinder

    Rajinder

    408
    7
    Jan 30, 2016
    Thanks. If I put 5mA through the sender, that should be ok? Would there be a problem with the differentiator part of the circuit, just to detect edges or is there a better way to achieve this?
    Best regards,
    Raj
     
  5. Alec_t

    Alec_t

    2,691
    712
    Jul 7, 2015
    Personally I'd use a CMOS Schmitt trigger, instead of a differentiator, to get sharp pulse edges.
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-