Help with Mic/Amplifier powering LEDs

Discussion in 'The Projects Forum' started by AndreaLynn, Oct 18, 2011.

  1. AndreaLynn

    Thread Starter New Member

    Oct 8, 2011
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    Hello, I have been stalking this message board for the past week hoping to be able to figure this out on my own with no luck.

    Basically I am trying to power as many LEDs as possible with a 9 volt battery (or a series of 9 volt batteries?), and for the lights to blink with music.

    I know there are a handful of threads like this that contain information and images of working schematics, the problem is I have NO background with circuitry, and as much as I've been trying to self-teach, I can't manage to figure out how to incorporate the mic and amp.

    I followed this tutorial and successfully got the lights to blink with an audio jack:
    http://www.youtube.com/watch?v=2o6w0ryH2dw

    And I have a mic element and a LM386 audio amplifier I got from Radio Shack but am confused how to integrate them. I also don't quite follow standard circuit schematics.....so I pretty much need a diagram with images that a complete dummy can follow :confused:

    I understand I'm asking for a lot, but you all seem very helpful and maybe will be compassionate to a fellow creator (my background is in costume making).....?

    I appreciate any help I can get!!
    Andrea
     
  2. AndreaLynn

    Thread Starter New Member

    Oct 8, 2011
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  3. Wendy

    Moderator

    Mar 24, 2008
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    I have an article that has a section you might find useful, Chapter 12, Flickering LEDs (Fire!)

    LEDs, 555s, Flashers, and Light Chasers

    As for the kit, was it MK103? We can help talk you through the troubleshooting if you'd like, DVM will be required.
     
  4. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Yeah, I think her kit was a MK103.
    If three of the LEDs are on, and the other is off, it sounds like there is a short right in the area of the LEDs.

    Look for a solder bridge or whisker across the traces.

    If you have a camera, it would help if you post photos.

    Just FYI, soldering is something that nobody is born knowing how to do. My first attempts at soldering resulted in huge wrinkled ovals of slag, so don't be embarrassed - everyone's been there at some point, particularly if they didn't have someone to teach them how to do it properly.
     
  5. AndreaLynn

    Thread Starter New Member

    Oct 8, 2011
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    Yes I do believe it is the MK103 kit.

    I will try to get a photo of what I did when I get home.

    If I get the kit/circuit figured out properly, can I use THAT as the board for the rest of my project?

    Meaning can I have wire coming from the positive of the first (of the four) LED space, then connect that to ALL of my LEDs (in parallel with resistors), and then back into the board at the last negative of the LED spaces on the kit?

    Or are the sizes/ohms of the resistors specific to lighting only four LEDs?
     
  6. Wendy

    Moderator

    Mar 24, 2008
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    The tutorial I posted on #3 will answer a lot of questions.

    Wookie is right, no one is born knowing this stuff. We pride ourselves strongly in helping beginners here at AAC, you do not have to worry about trolls.

    If one pops up, well, I've been a moderator for about 2½ weeks. It is now my job to take care of. :D Before then I just sic'ed the other moderators onto them.
     
  7. AndreaLynn

    Thread Starter New Member

    Oct 8, 2011
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    Thanks Bill!

    I looked over your tutorials. Unless I'm missing something, the flickering is controlled by the audio in from a radio, yes? :confused:

    I've been able to get LEDs flash to music using an audio jack and transistor like so:
    http://hacknmod.com/wp-content/uploads/2010/02/Building-the-circuit1.jpg

    (But with a 9v battery)

    And I've read the substitution of a condenser mic and amp in place of the audio jack SHOULD work to pick up sound....but I don't know what to connect where..
     
  8. Wendy

    Moderator

    Mar 24, 2008
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    Without a resistor you will have heat, and maybe smoke. Lots of smoke. LEDs do not control current, they depend on other parts (resistors) to do that.

    Can you take a close up picture of the top and bottom of the board, and post it here as two attachments? First step in trouble shooting is good visual inspection.

    In my tutorials I chose a radio. Audio is audio, the source is not critical.
     
  9. AndreaLynn

    Thread Starter New Member

    Oct 8, 2011
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    Yes! Sorry I realized later after I posted that the diagram doesn't have a resistor, I have one in front of my LEDs. I have a somewhat fair understanding of resistors (not DEEP understanding, just what they do and why they're necessary).

    I'll put up pictures tonight, thanks!
     
  10. AndreaLynn

    Thread Starter New Member

    Oct 8, 2011
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    0
    [​IMG]

    The front^^. The mic is out, you'll see why here:

    [​IMG]

    Blob of solder on the right where the mic was, then i noticed the soldering was a little sloppy so i tried to get it off.....and the result is the blob.

    I took it off because even when I had it the first time, the lights were just all on (except one)...no reaction to sound...

    Here's what I've made to flash with music....the mic and amp sit there waiting to be invited into in the fun...but they don't know how to kick audio jack out and include themselves...

    [​IMG]
     
  11. AndreaLynn

    Thread Starter New Member

    Oct 8, 2011
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    As you can see, the two wires coming from either side of the TIP31 are welcoming arms for the mic/amp...if only.....lol
     
  12. Wendy

    Moderator

    Mar 24, 2008
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    [​IMG]

    The areas I've circled need close inspection. One trace looks open, and their may be a solder short on the other.

    Do you have fine side cutters? Clip those wires off, they offer potential shorts. Nail cutters will also work, but you would probably ruin them doing this. The idea is the leads should be as short as possible.

    After you've done this get back with us.

    Overall the soldering job looks pretty good. Do you have a meter? It can tell you where you have an open when it should be connected, and visa versa.
     
  13. Audioguru

    New Member

    Dec 20, 2007
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    The You-Tube video shows a 12V AC output transformer instead of a DC adapter.
    It and the hacknmod circuit are the same terrible circuit (it is also an Instructable) that shorts the music amplifier (and might blow up the circuit and/or blow up the amplifier) and delivers much too much current to the LEDs which will blow them up and maybe also blow up the transistor.

    The Velleman kit is designed for only the 4 LEDs on it, not more LEDs.
     
  14. mcasale

    Member

    Jul 18, 2011
    210
    12
    I'll throw in my 2 cents also.

    I'm glad someone mentioned trimming the component leads. A "solder-sucker" might help to clean that up.

    I looked at the kit's schematic, and the 4 LEDs are in series, which makes a lot of sense (less power lost in the series resistor. If you are going to add more LEDs, here's something to consider -- the capacity of the battery. Look here http://en.wikipedia.org/wiki/Nine-volt_battery for info about 9V batteries. If a generic alkaline battery has 500 Milliamp-Hour capacity, and you drive 20mA through 1 string of lights, the battery should last for 25 hours. If you have 10 strings of LEDs (40 lights total), it will last about 2.5 hours. This all assumes linear aging of the battery and you start with a fresh one.

    Maybe that's about 3 cents' worth.
     
  15. Audioguru

    New Member

    Dec 20, 2007
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    Is a cheap Chinese battery (that is leaking already before being sold) a "generic" one?

    Look at the datasheet of the Name Brand Energizer 9V alkaline battery:
    1) With a load of 25mA its voltage drops to only 4.8V in about 25 hours.
    2) With a load of 200mA its voltage drops to only 4.8V in about 2 hours, not 2.5 hours.

    The LEDs will not light when the battery voltage is less than maybe 8V so the amount of operating time is much less.
     
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