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Powering LED strip

Discussion in 'LEDs and Optoelectronics' started by SparkyCal, Mar 11, 2020.

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  1. SparkyCal

    SparkyCal

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    Mar 11, 2020
    I'm almost embarrassed to ask this because I am such a newbie to electronics. But here goes: I have been reading about the theory, and also trying to follow Youtube videos, but I can't seem to get this to work.

    I have a breadboard and a 12 volt power supply.

    I have a LED strip that is powered by 12 Volts. It is about i/4 wide and about 4 inches long with three LEDS on it.

    My goal is to power this with a 12 volt battery (which i have). I would like to stick this LED strip on my guitar, right where the pickups are.

    The idea is to have it blink, as I play. It doesn't have to blink to the music. i just want to get it to blink.

    I have tried different circuits, but can't get it to work.

    Can anyone help by tell me what parts I need and how to wire it on my breadboard?

    Thanks so much! Sorry for such a basic question. i imagine most of you are masters at electronics.

    P.S. I have been trying to do this with a 2N2222A 1828 Transistor (those are the ones with the silver tin looking rounded heads and the Emitter, Base and Collector look like a tripod.
     
  2. bertus

    bertus

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    Nov 8, 2019
    Hello,

    What circuit did not work?
    What are the specs of the used ledstrip?

    Bertus
     
  3. SparkyCal

    SparkyCal

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    Mar 11, 2020
  4. bertus

    bertus

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    Nov 8, 2019
    Hello,

    The ledstrip you show has programmable controller chips on them.
    They get the commands from the remote control.
    Those are not so easy to let them blink.

    Bertus
     
  5. Bluejets

    Bluejets

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    Oct 5, 2014
    That's never going to work with your LED strip.

    One here on youtube uses 12V and a 5mm flashing LED to turn the gate of a mosfet on and off at the flash rate of the 5mm LED.
    In this particular case, this in turn operates the high power single 10W LED.
    All you would need to do is replace the 10W LED shown in the video to a section of your LED strip.

    It would naturally have to be a section that will operate from the 12V supply.
    The strip you link to has 150 LEDs in a 16ft strip. These would be divided into a number of smaller ( probably 3) LEDs , each with their own current limit resistor. A closeup photo of your LED strip showing say a 300mm section should conform this.
    I say 3 as I'm guessing each LED is around 3.5V, so 3 would be 10.5V and the current limit resistor for the last 1.5V.

    PS...ignore the little 9V smoke alarm battery that is a visual representation of a battery somewhere in the video.
    The unit will never operate on that either.

    https://www.youtube.com/watch?time_continue=247&v=Bc6aLoFsQkg&feature=emb_logo
     
  6. Martaine2005

    Martaine2005

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    May 12, 2015
    You can buy ‘flashing LEDs’ and ‘colour changing’ LEDs very cheaply.
    No circuit required.
    But I guess you went with the strip to stick it under the strings by the pick-ups?.
    You may find that the current/voltage plays havoc with the pickup coils. Best to check before final installation.

    Martin
     
  7. Bluejets

    Bluejets

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    Oct 5, 2014
    Chances are they are never going to flash in unison.......... if that is a requirement :)
    Don't think LED current will interfere with the pickup coils.
    They operate by the changing magnetic field right at the armature.
     
  8. Martaine2005

    Martaine2005

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    May 12, 2015
    Right, except the the magnetic field is driven by the string vibration . The bobbin is the coils. Normally 6 for all strings.
    Never heard of it as an armature. No internal spinning parts there.

    Martin
     
    davenn likes this.
  9. bertus

    bertus

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    Nov 8, 2019
    davenn and Martaine2005 like this.
  10. Bluejets

    Bluejets

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    Oct 5, 2014
    Well, there ya go as they say.
    I imagine you learn something new every day then.
     
  11. Martaine2005

    Martaine2005

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    May 12, 2015
    I tend to believe that every person on this planet learns something new every day.
    An armature for a guitar pickup is not one of them!.
    Maybe my learning ‘light’ will arrive by midnight?.
    I sometimes think your quick responses are a little harsh and sometimes just plain wrong. I don’t insult you with “there ya go then”,
    May be you could possibly explain what is wrong and explain why you think that.
    I really enjoy reading your in depth explanations of what you ‘really’ understand.
    However, I feel it’s better to link to a proven page of known accuracy and give credit.
    All the best

    Martin
     
  12. Bluejets

    Bluejets

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    Oct 5, 2014
    Grow up and get a life.
     
  13. SparkyCal

    SparkyCal

    43
    4
    Mar 11, 2020
    Hi. Thank-you for all the advice. I feel I need to start over and perhaps proceed in this manner:

    Here is what i have:

    A breadboard.

    A 12 volt power supply for the purposes of setting up and testing the circuit. I will eventually replace the 12 V power supply with a small 12v battery.

    I have a small LED strip that runs on 12v. Although it is meant to be a multi coloured LED powered by a special adapter, I have determined that I can just activate the blue LED by using the + terminal on the LED and the terminal marked B.

    The goal is to have this little strip sit just above my electric guitar pickup, and have it blink on and off.

    It is not to be synced up with the strings or the sound I am making out of the guitar. It is just to be a standalone blinking LED with no particular logic behind it, other than to blink.

    Can I accomplish this by using a resistor, a transitor (NPN) and a capacitor?

    I know that the transistor base wants a stepped down voltage (hence the resistor), in order to tell the collectoor and emitter to pass the 12v current through.

    But I simply do not know how to hook the components up into a circuit.

    Can anyone help me with that?

    Thank-you for your time and expertise.

    I appreciate it

    Charles
     
  14. Audioguru

    Audioguru

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    Sep 24, 2016
    A circuit to blink the LED on and off is called an oscillator but you described a transistor, resistor and capacitor that turns on and blows up the LED but it never turns off.
     
  15. SparkyCal

    SparkyCal

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    Mar 11, 2020
    I am obviously confused ;-(
     
  16. Audioguru

    Audioguru

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    Sep 24, 2016
    You are probably talking about this extremely simple circuit that does not always work. It has the transistor connected backwards so that it has avalanche breakdown causing it to oscillate sometimes and to burn out the LED frequently.
    A real oscillator always oscillates.

    You confused everybody because you did not post the schematic with your "resistor, transistor (NPN) and capacitor". Here it is that blows up the LED:
     

    Attached Files:

  17. SparkyCal

    SparkyCal

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    Mar 11, 2020
    Sorry....I said i was a newbie. Thank-you. I will need to reframe my efforts/
     
  18. SparkyCal

    SparkyCal

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    Mar 11, 2020
    Ok...I think I am close to what i want to achieve. I actually have a circuit that uses a 1 K resistor, a BC 547 transistor and a 47uF capacitor using a red LED. I actually got it blinking, however I am sure I have the correct capacitor called for in the circuit. The one I am using, says it is 47 uF, 63 volts (it has a green cannister, made by JWCO.

    The only trouble is, the LED does not blink at 12 volts. It blinks when i raise the voltage to 12.90. At 12 volts, it does not blink at all.

    I wonder if it is because I am using the wrong capacitor? I need to make it woerk at 12 volts. Does anyone know wha I need to tweak/change?

    Here is the circuit I am following.



    The good news is, I am understanding how to follow the schematic, but I don 't know why it does not blink at 12 volts.

    Also. my end goal is to use this type of circuit to make a 12 volt led strip blink. So maybe my question should be, what tweaks do i need to make to use this same circuit, with the end goal of making the 12 volt strip blink. To simplify things, think of the 12 volt strip as being a normal lamp that has a positive and negative terminal, because that is how it functions.
     
    Last edited: Mar 17, 2020
  19. Audioguru

    Audioguru

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    Sep 24, 2016
    Look at the datasheet of your BC547 to see which pin is which. It is different to an Oriental or an American transistor.

    You probably will not make an LED strip with this extremely simple circuit because an LED strip usually has some LEDs in series.
    The LED strip can blink if it uses an oscillator to drive it.
     

    Attached Files:

  20. duke37

    duke37

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    Jan 9, 2011
    The circuit you show uses breakdown of the transistor when connected the 'wrong' way round. This is not good for the transistor. Too low a voltage will not cause breakdown so it will not oscillate.
    I would use a CMOS 4093 as an oscillator and a transistor to power the strip. A capacitor and resistor would be used for timing.

    Any wire with a current through it will cause a magnetic field. Whether this will cause problems is another matter.
     
    Martaine2005 likes this.
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