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  1. #101
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    Re: Help re-creating a replica movie prop

    Hi,

    Quote Originally Posted by skarkowtsky View Post
    I appreciate the effort here, gents. Thank you. But, I'm going with the YouTube video I posted last night--it's just easier for me. Even with your video, I don't know how to even start this circuit.

    A couple of questions:
    How can I add the 12 toggles to the YouTube circuit?
    What would I need to adjust pitch and duration? Just different values of capacitors and resistors? I need a higher pitched tone and shorter duration than what was in your video, D123.

    Thanks again!
    John
    Let me break this to you (not especially) gently, John. You can't use a monostable timer to drive a speaker because a speaker is an oscillatory device, it has a (paper) membrane that needs to oscillate to make any sound - otherwise it will just make a pathetic, barely audible crackle. The YouTube video you posted is no use to your objective, unfortunately, unless you use a DC buzzer and that will limit the sound you can reproduce to the default buzzer sound. That removes the need to answer the first question. The second question is (with an astable 555 circuit): use a smaller capacitor around the speaker and a smaller capacitor from pins 2 and 6 on the astable timer (the one to the right).

    I fail to understand why a person who makes a seven-segment display circuit function - who says they had no prior electronics experience - thinks they are unable to make a simple 555/556 circuit, it seems more like stubborn caprice than truthfulness. I remember the start of this thread and you fussed over suggestions and pretty much went back to the first one suggested to you, here we go again.

    Lastly - I just wanted to help you, so don't bother with the "helped me" button, it's not about "points mean prizes" for me - I'll guess that in this film you're the star of here on the forum you haven't been able to notice that people on this forum show their gratitude to the people who help them by pressing the "helped me" button, give it a try sometime and be a little less selfish/self-centred.

    Sorry to be honest with you, it's not very glamour and showbiz but it is all fair comment by now...

    Anyway, you need an astable timer and you're more than capable of putting that 556 circuit, or two 555s, together by yourself.

    Good luck and hope it all works well for you. Thanks again!

    See you!



  2. #102
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    Re: Help re-creating a replica movie prop

    The toggles are the switches you already have in your existing design, you just wire the end of the diode to the existing switch that activates the display. The idea is that the diode only conducts in one direction so there is no path for any switch to interfere with another - but - any of the switches closing will trigger the beep.

    Yes, the values control the length of beep and it's tone. Using the schematic in post #99, the resistor and capacitor on pins 1 & 2 of the first timer decide the length, dropping either value will make the beep shorter. I would suggest dropping the 82K value is easiest but don't go below about 1K. I would guess you want a beep about half as long so drop it to half value, maybe 39K or 47K standard values.

    The idea of the first timer is it produces a fixed length single pulse when triggered by a switch closing, without it the tone would be present whenever a switch was closed. We call it 'mono-stable' timing, meaning the circuit only has one stable state which it changes to and stays at after the timing period has elapsed. The pulse is used to activate the second timer and sets the length of the beep.

    The second timer is the same type of device (or other half of a dual device) but it is wired in 'astable' mode. An astable timer resets itself and keeps repeating, it doesn't have a stable state so it oscillates between two conditions. The resistors and capacitors on pins 8, 12 &13 decide how quickly it changes state and the values show make it change around 800 times a second. It is that 800 cycle changeover that drives the loudspeaker and produces the tone you hear. Again, the values decide the frequency and lower values result in shorter times which means higher pitch. In astable mode, both resistors will set the pitch but they work in slightly different ways, there are some combinations of values that will not work so I recommend dropping the capacitor value (pins 8 & 12) instead. Try 47nF to roughly double the pitch.

    The pulse turning the beep on and off from the first stage goes into pin 10 of the second stage. It holds the astable part in a reset state (not oscillating) unless it is enabled by the pulse from the monostable part. So the sequence is: switch closes, monostable produces a short pulse, pulse activates astable, astable output drives speaker to make tone, pulse ends, speaker goes silent.

    Brian.
    PLEASE - no friends requests or private emails, I simply don't have time to reply to them all.
    It's better to share your questions and answers on Edaboard so we can all benefit from each others experiences.


    1 members found this post helpful.

  3. #103
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    Re: Help re-creating a replica movie prop

    Quote Originally Posted by d123 View Post
    Hi,



    Let me break this to you (not especially) gently, John. You can't use a monostable timer to drive a speaker because a speaker is an oscillatory device, it has a (paper) membrane that needs to oscillate to make any sound - otherwise it will just make a pathetic, barely audible crackle. The YouTube video you posted is no use to your objective, unfortunately, unless you use a DC buzzer and that will limit the sound you can reproduce to the default buzzer sound. That removes the need to answer the first question. The second question is (with an astable 555 circuit): use a smaller capacitor around the speaker and a smaller capacitor from pins 2 and 6 on the astable timer (the one to the right).

    I fail to understand why a person who makes a seven-segment display circuit function - who says they had no prior electronics experience - thinks they are unable to make a simple 555/556 circuit, it seems more like stubborn caprice than truthfulness. I remember the start of this thread and you fussed over suggestions and pretty much went back to the first one suggested to you, here we go again.

    Lastly - I just wanted to help you, so don't bother with the "helped me" button, it's not about "points mean prizes" for me - I'll guess that in this film you're the star of here on the forum you haven't been able to notice that people on this forum show their gratitude to the people who help them by pressing the "helped me" button, give it a try sometime and be a little less selfish/self-centred.

    Sorry to be honest with you, it's not very glamour and showbiz but it is all fair comment by now...

    Anyway, you need an astable timer and you're more than capable of putting that 556 circuit, or two 555s, together by yourself.

    Good luck and hope it all works well for you. Thanks again!

    See you!
    Whoa,

    You just flew off the handle. Chillax. I'm not sure why you're taking this personally, or why I have to beat a dead horse and reiterate that I just don't comprehend the 555 circuit. The 7 segment circuit was much easier for me to understand. I can't tell you why.

    As for the Help button: I have under 60 posts on this forum, sometimes I notice the button, most times I don't. I'm still new here and don't know the culture. It's not matter of me being self-centered or selfish. It was an honest oversight. You're being way too presumptuous about a person you've never met in the real world. No harm was meant toward your ego, which seems damaged and overly sensitive. But definitely not by me and my trivial posts about electronics.

    There's a difference with you being honest and being way off base. Unfortunately, it's the latter.

    Again, not sure why you are so upset with my decisions. I don't discount your knowledge or effort, I just don't understand the circuit because I'm inexperienced. You're welcome to remain in this thread and I'll forget your infantile outburst and gross generalization of my character, as I've enjoyed our conversations.

    J

    - - - Updated - - -

    Quote Originally Posted by betwixt View Post
    The toggles are the switches you already have in your existing design, you just wire the end of the diode to the existing switch that activates the display. The idea is that the diode only conducts in one direction so there is no path for any switch to interfere with another - but - any of the switches closing will trigger the beep.

    Yes, the values control the length of beep and it's tone. Using the schematic in post #99, the resistor and capacitor on pins 1 & 2 of the first timer decide the length, dropping either value will make the beep shorter. I would suggest dropping the 82K value is easiest but don't go below about 1K. I would guess you want a beep about half as long so drop it to half value, maybe 39K or 47K standard values.

    The idea of the first timer is it produces a fixed length single pulse when triggered by a switch closing, without it the tone would be present whenever a switch was closed. We call it 'mono-stable' timing, meaning the circuit only has one stable state which it changes to and stays at after the timing period has elapsed. The pulse is used to activate the second timer and sets the length of the beep.

    The second timer is the same type of device (or other half of a dual device) but it is wired in 'astable' mode. An astable timer resets itself and keeps repeating, it doesn't have a stable state so it oscillates between two conditions. The resistors and capacitors on pins 8, 12 &13 decide how quickly it changes state and the values show make it change around 800 times a second. It is that 800 cycle changeover that drives the loudspeaker and produces the tone you hear. Again, the values decide the frequency and lower values result in shorter times which means higher pitch. In astable mode, both resistors will set the pitch but they work in slightly different ways, there are some combinations of values that will not work so I recommend dropping the capacitor value (pins 8 & 12) instead. Try 47nF to roughly double the pitch.

    The pulse turning the beep on and off from the first stage goes into pin 10 of the second stage. It holds the astable part in a reset state (not oscillating) unless it is enabled by the pulse from the monostable part. So the sequence is: switch closes, monostable produces a short pulse, pulse activates astable, astable output drives speaker to make tone, pulse ends, speaker goes silent.

    Brian.
    Thank you, Brian.
    Last edited by skarkowtsky; 7th December 2018 at 00:29.



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