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LEDs Sync To Music

Discussion in 'Electronic Projects Design/Ideas/Reviews' started by FreeTrial, Jun 6, 2006.

  1. PCBWING

    PCBWING New Member

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    I remember a book called "zero-based learning circuit," as you all say, thank you! I learned a lot of knowledge.
     
  2. grsmith021

    grsmith021 New Member

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    isolating bass from audio jack

    i have built the tip31 transistor led circuit that was described earlier in this thread, but i was wondering if anyone knew how to isolate the bass from the audio so that i can have the leds pulse to not only right and left audio but also to the bass.

    i bought a 1.5 mH audio choke in the hopes that i could choke out the other frequencies and leave behind the bass, but i really am not sure how to use it. any help would be greatly appreciated!
     
  3. audioguru

    audioguru Well-Known Member Most Helpful Member

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    The TIP31 circuit is missing a few very important parts. It can easily blow up itself and/or blow up the stereo it connects to.

    A single choke makes a gradual poor quality lowpass filter if the circuit and its value are designed together. An active lowpass filter using a transistor or an opamp is much better.
     
  4. dave

    Dave New Member

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  5. grsmith021

    grsmith021 New Member

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    ok thanks, basically what i am trying to ask is if there is any easier, inexpensive route to getting the bass with only using the choke, especially since ive already purchased it haha
     
  6. rudster

    rudster New Member

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    alright I got the circuit to work with 1 led now i need to know how to make a circuit for about 87 smds in 3 series and parallel. its for my car it requires 12V 5A
     
  7. samalert

    samalert New Member

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    No use of amp or caps or resistors since am unable to understand the diags
    Few questions for HELP
    > my leds are much dimmer how to increase the intensity
    > even two set connected to diff channels left and right but both blink the same no diff in blinking, what might be wrong?
    > how to seperate frequencies high mid low

    what i did is hooked 3xtip31 to 3set of leds one with left and other with right and the last with combination of left+right but all blink the same with low intensity HELP
     
  8. audioguru

    audioguru Well-Known Member Most Helpful Member

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  9. samalert

    samalert New Member

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    Thanks for replying i know the thread is old but OLD IS GOLD :)

    Have attached the circuit this time exact what i have designed

    > Amplify the input signal
    How to do that have heard of LM386 or op amp($10) what they say to improve the signal but dont know the circuit moreover they are costly what i think isnt it.Also i have seen circuits where they dont use those but still get brighter display of LED's so am confused.

    Please let me knw how to amplify in cheap

    >Bass sound in mono
    I have done that in last strip of led right+left = mono isnt it ? if am not wrong
    since during these many days i have found that connecting these two channels create a mid pass filter which is not with me

    All blink same nothing diff and all with same intensity

    > and lastly about separating frequencies
    i have seen those but since am not a electrical student i am not aware of those, those are like cryptic symbols and am not able to understand.

    USB.JPG
     

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  10. audioguru

    audioguru Well-Known Member Most Helpful Member

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    If the input is from a microphone, a line level or a headphones level from an ipod then you need an amplifier.
    An LM386 costs only $.93US from Digikey today. They have more than 10,000 in stock.
    An LM386 is a little power amplifier that amplifies as much as you want and is powerful enough to drive up to 36 LEDs.

    You are simply shorting the two channels together which will destroy an amplifier if the input signals are speaker levels. Then all of your outputs are mono. You are supposed to use an audio mixer circuit to make mono. Some audio mixers are simply two resistors.
    Your circuit has no filter. You need an active bandpass filter or an active lowpass filter to make only bass sounds.

    Because you simply shorted the left and right channels together so they produce mono exactly ther same.

    There are many circuits on the internet that use inexpensive opamps to make active filters.

    1) Your circuit is missing input resistors so the base-emitter junction of each transistor shorts the input signal which will destroy a speaker amplifier and/or destroy the transistors.
    2) Your circuit is missing rectifier diodes so a speaker level will destroy the transistors (their max allowed reverse voltage is only 5V).
    3) Your circuit is missing resistors to limit the current to the LEDs. Then the LEDs burn out.
    4) Your circuit has LEDs in parallel which is wrong because all LEDs are different. An LED with the lowest forward voltage will hog all the current and burn out. Then the next LED with the lowest forward voltage will burn out.

    Since you know nothing about electronics then I suggest that you buy a kit for a color organ.

    I designed this circuit that will drive up to 18 LEDs. If you make it with two LEDs in series replacing each single LED then it can drive up to 36 LEDs. It has no filters.
     

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  11. denno

    denno Member

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    sorry to jump in just here, but I was wondering, instead of the 1N4001, can I use another diode? Specifically, could I use a 1N4148 or a 1N5404. These are the two diodes I currently have in my electronics kit, so it would be great if I could swap out and use something that I already have :).

    Thanks
    Denno
     
  12. audioguru

    audioguru Well-Known Member Most Helpful Member

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    A 1N4148 can be used if you have only 18 Leds or less. A 1N5404 rectifier has a fairly high voltage drop (a 1N4001 is lower) but will work. My solar garden lights have some 1N5817 Schottky diodes that will work great.
     
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  13. denno

    denno Member

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    Thanks mate :)
     
  14. bhavish.as

    bhavish.as New Member

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    hey audioguru could you gimme an explanation of how the led's glow when audio input is applied??
     
  15. audioguru

    audioguru Well-Known Member Most Helpful Member

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    It is a very simple circuit.
    The LM386 is not an opamp, it is a power amp designed to drive a speaker. With the 9V supply its output is 3V peak which is 3V into 8 ohms= 375mA. It can drive 375/20= up to 18 LEDs that draw 20mA each.

    The amplifier has internal biasing that makes the output pin5 usually average at +4.5V.
    The 22k and 1k resistors bias the (-) input a little positive which causes the output pin5 to average as low as it can go .
    The diode conducts when the output swings positive and charges the upper 1000uF capacitor to maximum voltage of about +6V which lights the LEDs.

    The capacitor slowly discharges so the LEDs are lighted for enough time that you can see the light.

    The lower 1000uf capacitor smoothes the 9V supply which will jump up and down without it if a little 9V battery is used.
     
  16. bhavish.as

    bhavish.as New Member

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    thanx a lot audioguru.. that really helped me a lot...

    but what i dont understand is how to give the input.. how can i connect the headphone to the 10k potentiometer.. one end that is the 3.5mm audio jack which is connected to the laptop but how do i connect the other end to the potentiometer... and i've done my complete circuit in a breadboard.. does it make any difference??
     
  17. audioguru

    audioguru Well-Known Member Most Helpful Member

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    You do not connect the headphone to the volume control, instead you connect the headphone output or a line level output from the audio source.
    Use a shielded audio cable with a 3.5mm plug (not jack, the laptop has the jack) at one end. If the audio source is stereo then you can add the two channels together at the input of the volume control with a 1k series resistor from each channel.

    The circuit might oscillate at a very high frequency and the many long wires might pickup interference if the circuit is made on a breadboard.
     
  18. bhavish.as

    bhavish.as New Member

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    thanks a lot audioguru
    i could make mine work after all
    i would not be able to do this without your help
    thank you again!!!:D
     

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