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Electronics illiterate seeks assistance! LOL

Discussion in 'General Electronics Discussion' started by Macster, Sep 16, 2011.

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  1. Macster

    Macster

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    Sep 16, 2011
    Hello folks, I figured the best possible place for a taxidermist to get assitance with an electronics question would be here in an electronics forum!:) I am working on a project with my Father and I have not messed with electronic components since I was in high school too many years ago. What we are wanting to do is create a circuit that does the following:
    1 - Be activated by sound and turn on a light (LED) - BUT
    2 - there must be an adjustable (between 1/4 to 1 full second) delay prior to turning the light on and
    3 - maintain the light on (preferably adjustable) up to one full second.

    I found a basic kit in Radio Shack to play with that turns on LED's by sound but I am absolutely clueless as to what would be needed component-wise that would allow the seperate delays.

    Your assistance is greatly appreciated!

    With respect - Mac
     
  2. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,501
    2,841
    Jan 21, 2010
    Hahahaha, I can almost see it. Walk into a darkened room and one by one all the eyes of the animals mounted on the wall begin to glow... And then go out.

    There are several ways to do this, and how you do it depends a lot on your skill(s), how many of these you want to produce, and exactly what you want it to do.

    I note that you say "adjustable" insead of "variable" That's important, because to me it says that you want to set it and have the delay fixed. The alternative might include a delay which varies randomly -- and that is a lot harder.

    The three points you've broken down your description into also match the various modules inside a straightforward implementation of this.

    1) amplifier and trigger
    2) monostable (delay) prior to triggering next stage.
    3) monostable (delay) turning on the LED.

    The radio shack kit you've refered to is probably the equivalent of part (1)

    Then you need to use this to trigger a delay (adjustable from 1/4 to 1 dec)

    Then the falling edge of this output triggers another monostable which holds the LED on for an (adjustable?) time of about 1 second.

    This may all still be above your head. But there are some technical questions. The main one is whether the delays are retriggerable.

    If they are retriggerable, the first delay (before the LED comes on) will not start until the sound stops. If they are NOT retriggerable, the first delay will start as the sound starts. (Which do you want?)

    Making the second one retriggerable or not would have a more subtle effect, but I'd go for retriggerable as it wouldn't be so prone to suffering from brief "off" times between the LEDs being on.

    Once we know what you want, we may be able to come up with something, or point you to a device (or kit) which already exists. If you have some programming skill, everything except the actual sound detection could be done in software using a microcontroller (I'd recommend a PICaxe). See this thread for a recent example of the sort of thing you need to do.
     
  3. Macster

    Macster

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    Sep 16, 2011
    ,Thank you for the response Steve

    Don't let taxidermist fool you, that is my fun "2nd Job". My primary is Assistant QA Manager at shipyard. I have a pretty good mechanical background and have a basic electronics understanding but it has been a long long time since I played with something like this. I really do like your idea regarding the eyes and will look into that!:D I truely understand the concept you are describing though yes, there is some that is a bit above my line of thought. I truely appreciate your assitance with this!
    Mac
     
  4. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    2,841
    Jan 21, 2010
    You really need to decide whether you want a microcontroller solution to the poblem (which has huge benefits in flexibility, but requires you get your head around programming the thing) or one based on timers and/or logic. The latter approach is perhaps less flexible once built, but may be one which you are more comfortable with.

    The initial detection of sound may be as simple as an electret mic insert amplified by a op-amp. You would need some sort of variable gain to set the sensitivity to an appropriate level.
     
  5. Macster

    Macster

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    Sep 16, 2011
    Posted by Steve "You really need to decide whether you want a microcontroller solution to the poblem (which has huge benefits in flexibility, but requires you get your head around programming the thing) or one based on timers and/or logic. The latter approach is perhaps less flexible once built, but may be one which you are more comfortable with."

    This may be the more practical way to go though it now increases the learning curve. Review of the link you provided appears to me to be something along the VB type of programming. I would not believe that it is too difficult (provided the KISS concept is utilized) and will take some homework and inquiry to get the functionality I am after. The overall package for this I am attempting to make the size of an electronic guitar tuner so if I can reduce size by a programmable component that will replace two seperate others, it appears to be the logical way to go. (Understand I am speculating this is the case in my thought here :rolleyes:)

    "The initial detection of sound may be as simple as an electret mic insert amplified by a op-amp. You would need some sort of variable gain to set the sensitivity to an appropriate level. "

    Agree, the kit I have purchased, the velleman MK103RS uses a small mic but I do not believe that it has an op-amp. That is OK, just getting a functional unit is step one.

    I am open for going either direction with this build and have purchased round PCB to play wiht once I found out what I needed and where in the circuit I need to put it.

    I hope this helps - keep the questions comin, your questions help me learn!

    Mac
     
  6. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,501
    2,841
    Jan 21, 2010
    OK, so are you talking about a single normal LED? Or something higher powered and/or more elaborate?

    The manufacturers of the PICaxe provide a lot of information. Here is something they produce about sound input.

    You do need some hardware and software to program the PICaxe, but it is very cheap and easy in comparison to using a typical microcontroller.

    I'd advise you to build the circuit up on a breadboard at first. If/when you go to a PCB or veroboard, you can (and probably should) keep the programming interface so you fix any bugs you find later.
     
  7. Macster

    Macster

    4
    0
    Sep 16, 2011
    Thanks Steve,
    The information from Picaxe is very interesting albeit over my head in areas, but taught me some things I did not realize and am taking into consideration. Regarding the LED, yes, a single basic high visability LED is all that is needed for the indicator.
     
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