Adding a beep to every second.

Discussion in 'General Electronics Chat' started by 06awaism, Feb 2, 2013.

  1. 06awaism

    Thread Starter New Member

    Feb 2, 2013
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    Hi, How can I add a loudspeaker to this schematic below so that it beeps every second and how would I go about doing that? The potentiometer(VR1) in this schematic is to change the speed of the timer. So when I change the speed of the time, the beep of each second should change accordingly. Any detailed answers or guidance will be appreciated. Also, I am having difficulty constructing the RESET switch part of this schematic on to the breadboard, so what connections do I have to make to the RESET switch e.g pin 15 of IC4026 to pin 1 of the RESET switch etc. If have written a summary of the function for this circuit if you require any further information. Thank You.

    (When the switch is opened/off, the timer starts counting up to 99 seconds displayed on the 2 digit 7 segment display. And when the switch is closed/on, then the timer stops on the second it is on and stays halt until or unless the Reset switch is pressed and start counting from 0 only if the switch is opened/off.)

    [​IMG]
     
  2. tracecom

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    Apr 16, 2010
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    Without knowing the value (or at least the range) of VR1, it is not possible to calculate the clock frequency, but if it is 1 Hz, then you can simply add a tone source at pin 3 of the 555. The duration of the tone will be for as long as pin 3 is high, which would be just over 1/2 second.
     
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  3. 06awaism

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    Feb 2, 2013
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    Thanks for the reply, but where is the R2 located in this schematic?
     
  4. tracecom

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    I don't know the details of the reset method of the 4026; you should look at the datasheet for details. But in general, a reset circuit consists of a pull-up resistor to Vcc and a switch to ground with the junction of the resistor/switch connected to the reset pin. In some cases, it is the reverse, i.e., a pull-down resistor to ground and a switch to Vcc with the junction of the resistor/switch connected to the reset pin.
     
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  5. tracecom

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    It is VR1 that I meant to ask about.
     
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  6. 06awaism

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    Feb 2, 2013
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    It is a 100K potentiometer.
     
  7. tracecom

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    Then, the minimum frequency will be with VR1 set to its maximum of 100k, and will be .689 Hz. In order to have the pulse frequency at .5 Hz, you would need VR1 set to about 140k. What is the range of pulse frequencies you are trying to get from the 555?

    ETA: Setting VR1 to 67k will give one pulse per second; is that what you want?
     
    Last edited: Feb 2, 2013
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  8. 06awaism

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    Feb 2, 2013
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    Yes sir. But will it be possible if it could alternate? So just increasing the speed of the timer below the 67k would also increase the beeping per second. But setting to 67k for VR1 seems just fine.
     
  9. tracecom

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    OK, then you can connect a tone generator to pin 3 of the 555. You can use a piezo beeper, which is probably the simplest way. Or you can build a tone generator. Look at the datasheet for the 555 you are using to determine the current it can source at pin 3, and choose a tone generator that can operate on the current from the 555.
     
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  10. 06awaism

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    How can I build a tone generator, Can you elaborate on the instructions you have given me please as I am newbie. Thank You.
     
  11. tracecom

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    Google "tone generator circuit" and you will see many choices. Consider what components are required and what components you have, the power required for each one, and then post here with your choice. Someone will probably be able to help.
     
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  12. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    You could get a piezo buzzer that had the oscillator circuitry built in, so only voltage needs to be applied.

    Then only a transistor driven from pin 3 is needed to power the buzzer on and off.
     
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  13. 06awaism

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    Feb 2, 2013
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    Hi, there are loads of buzzers on this page, but don't know which kind of buzzer with oscillator I need. So can tell me from the list from this URL please.
    Thank You

    http://www.maplin.co.uk/productsearch?criteria=piezo+buzzer
     
  14. thatoneguy

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    Typically, the ones that say "buzzer" or "siren" have the oscillator in them, while the ones that say "transducer" or "piezo element" do not.

    If they mention tone or siren, they usually have the oscillator in them, and the frequency is in the specifications/data sheet on that site.
     
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  15. ScottWang

    Moderator

    Aug 23, 2012
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    You can use another 555 astable oscillator to be the tone generator.

    1. The R1 of 555 tone generator connecting to the Pin 3 of 555 Timer.
    2. The Pin 3 of 555 tone generator connecting a cap from 10uf~100uF and add a resistor less then 100Ω or add a 10Ω+VR100Ω and connecting to speaker(Buz), the other pin of speaker connecting to ground, using VR100Ω to adjust the volume of speaker(Buz).

    Here is a circuit is similar as I mentioned.
     
    Last edited: Feb 4, 2013
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  16. 06awaism

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    Feb 2, 2013
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    Thanks A lot for the instructions. But I am a little confused. What is the R1 as there is no R1 of the added 555 timer. Also, are you assuming that the another 555 timer which I will be adding is the tone generator and when you say 555 timer, it is the IC 555 timer that is already being used in this schematic? Thank You.
     
  17. ScottWang

    Moderator

    Aug 23, 2012
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    Sorry for your confused.
    Maybe I should say 555 1Hz timebase instead of 555 timer, that's your original 555, and the new 555 is a 1Khz tone generator to generate a beep sound.
    I meant that you should add another 555, so the R1 that I mentioned is the same function as the 555 1Hz timebase.
    The R1 in 555 1Hz timebase is connecting to Vcc, but the R1 in 555 1Khz tone generator should connecting to Pin 3 of the 555 1Hz timebase, I tried this kind of function before, but I haven't try the way of the linked page that I mentioned, you also can try as the linked page shown that the pin 5 of 555 tone generator is connected to the pin 3 of the left 555.

    When you using NE555, it meant that you want to use a clock is not precise, you can use another way to do more presicely, that's using CD4060 and CD4013 as below :

    1Hz Timebase -- using 32768Hz crystal and CD4060,CD4013.
    [​IMG]
     
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  18. 06awaism

    Thread Starter New Member

    Feb 2, 2013
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    Hi, thanks a lot for giving me your time. I have few questions if you are happy to answer them in detail please if you don't mind:

    1: The speaker or buzzer beeping using 555 timer is what I have used accordingly to your instructions and here is the schematic:



    [​IMG]

    I have simulated but the buzzer is out of phase and does not beep accordingly to the timer in seconds. What am I doing wrong?

    2: You said I could use the crystal, IC4060(there are 2 chips on this website, which one do I need? http://www.maplin.co.uk/productsearch?criteria=4060) and IC 4013. So How can I connect a 8 Ohm Speaker to the diagram you showed me and then how would I join this schematic with the timer?

    3: And finally, if I used the crystal, IC4060 and IC4013, will it be very precise and accurate? And also using this method, if I changed the speed of the timer in seconds using the 100K potentiometer as I have used in the schematic to make the time go slow or fast, will the beeping also go slow or fast accordingly to the change I make in the speed?

    Thank You Very Much Sir
    [​IMG]
     
  19. ScottWang

    Moderator

    Aug 23, 2012
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    When you simulating the circuit, you should choose the power voltage in the real world that you can use, like as the power of Buz should be match the Vcc, otherwise you can add a resistor to try)

    You had wrong idea, the 555 1Khz tone generator should be a independent circuit, it has its own capacitor,R1 and VR1, otherwise it doesn't like as an oscillator, the R1 of 555 1Khz tone generator should be disconnect from Vcc and connecting to the pin 3 of 555 1Hz timebase.

    Because the frequency is 32768hz, it's not so high, so you can choose anyone of them.

    CD4060+CD4013 1Hz timebase → NE555 1Khz tone generator → Buz. (the power of Buz should be match the Vcc, otherwise you can add a resistor to try)

    CD4060+CD4013 1Hz timebase → NE555 1Khz tone generator → 10uf~100uf → 10Ω+100Ω → Speaker → GND

    If you using CD4060 CD4013 to be the 1Hz timebase, then you will raising the precision and the error value about 1/32768,because the 1Hz is the 32768Hz divided by 32768.

    When you using the new 1Hz timebase(CD4060+CD4013), then you will no 100K potentiometer to adjust, if you need to do that, then you just use NE555.

    You can attach your circuit on this site.
     
  20. 06awaism

    Thread Starter New Member

    Feb 2, 2013
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    Hi, Thank you very much again. Here is the circuit. Is it alright? I have simulated and works but the duration of beeping is too long so how can I solve that? Also, is it okay if I asked you for any help if I need it in future? Thank You.

    [​IMG]
     
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