Need help with Music Sync to LED project

Discussion in 'The Projects Forum' started by mosaics, Feb 25, 2013.

  1. mosaics

    Thread Starter New Member

    Feb 24, 2013
    8
    0
    Hi, I found out about this website from a friend and it really help him a lot. So hopefully this help me with my project too.
    Im currently making an LED sync with music for my school project. I decided to do this project because of a video on youtube and it really looks cool!

    This is the circuit diagram I found and tried it on multism:
    [​IMG]

    And it worked using an LF347N IC OpAmp and TIP31A transistor. I transpose them to the ultiboard to make the PCB.

    This is what I get:
    [​IMG][​IMG]

    The green and blackish-green wire is the left & right input connected to my computer headphone jack. And two reverse supply of 9V battery each on pin 4 & 11.
    Well, it didnt worked this time....
    I dont know where I go wrong and my professor dont even know what to do "orz
    So Im left with the community on this site to point out my mistake and help me with the construction of this circuit.
    Thank you.

    PS: Ive tried the simple circuit with just the transistor, resistor and LED. But the professor wont accept that.
     
  2. bertus

    Administrator

    Apr 5, 2008
    15,646
    2,345
    Hello,

    There are some things not right with your circuit.
    1) the transistors are differently biased.
    2) leds may not be connected in parallel directly.

    Here is a block diagram of how I would do the circuit:

    [​IMG]

    You will have to create the schematics in the blocks yourself.

    Bertus
     
  3. mosaics

    Thread Starter New Member

    Feb 24, 2013
    8
    0
    Thanks, Ill try that. I will post up more question if I run into any problem :)
     
  4. mosaics

    Thread Starter New Member

    Feb 24, 2013
    8
    0
    Ive search around for a bit and found the circuit diagram on each blocks, it looked kind of complicated.
    Can you explain more on my different bias transistor? Because I just followed what the circuit diagram stated, Base goes here, Collector goes to LED and Emitter goes to ground, etc.
    Actually, Im a bit confuse with the ground on pin 4 & 11 after the battery supply, where should I connect the ground? And also the Left and Right wire, where should it go to?
     
  5. bertus

    Administrator

    Apr 5, 2008
    15,646
    2,345
    Hello,

    When looking at your schematic I see the following:
    The bases of Q1 and Q3 are hold down by resistors, they can only be activated with a large AC signal via the capacitors.
    The base of Q2 is connected to the opamp with a resistor.

    The leds are connected in parallel with only one resistor, this may cause failure of the leds.
    Each led should have its own current limiting resistor.

    Bertus
     
  6. mosaics

    Thread Starter New Member

    Feb 24, 2013
    8
    0
    So that means I just have to take out the resistor at Q1, Q2 & Q3 and directly connect the capacitor to the opamp?

    Im sorry if I sound like an amateur sir, because I am. And this could make a learning experience for me.
     
  7. bertus

    Administrator

    Apr 5, 2008
    15,646
    2,345
    Hello,

    In my block diagram, you will see one amplifier at the entrance.
    This is feeding three filters.
    These can be active filters using opamps.
    Then you see three peak detectors.
    These will smoothening the signal from the filters.
    Then you see three led drivers.
    These may each consist of a comparator (so you can adjust the sensitivity) and a transistor.

    Bertus
     
  8. mosaics

    Thread Starter New Member

    Feb 24, 2013
    8
    0
    I see, that explains a lot :D thanks!
    Ill try to make the schematics later on and post it up here.
     
  9. sheldons

    Active Member

    Oct 26, 2011
    616
    101
    if you want something ultra simple which works......try this....
     
  10. mosaics

    Thread Starter New Member

    Feb 24, 2013
    8
    0
    That look simple enough, but some question I would like to ask, whats that Q4? (beside the text BUZ90) is it a transistor? because I never saw that type before. And also the V1,1, what is that?
    Second, I can use a mono/stereo jack connected to a computer input instead of a mic right?
    Thanks.
     
  11. mosaics

    Thread Starter New Member

    Feb 24, 2013
    8
    0

    I tried making the schematics, but I cant connect them into one circuit diagram. Do i need to use 2 opamps IC for this?
     
  12. mosaics

    Thread Starter New Member

    Feb 24, 2013
    8
    0
    I was ask to redo the circuit again on a strip board lol. Im sticking with the original circuit diagram I made since it worked with Multism. I just have to figure out where to put the component on the board. And I have to submit this by Thursday, wont have time to start everything from scratch.
     
  13. sheldons

    Active Member

    Oct 26, 2011
    616
    101
    the buz90 is an n channel fet,the other symbol is an opto isolator...the circuit started out as a means of testing optos ,its quite simple to build and it works well-
     
Loading...