White LED strip doesn't light up with arduino uno

Discussion in 'General Electronics Chat' started by Ali Ashley, Mar 18, 2016.

  1. Ali Ashley

    Thread Starter New Member

    Mar 18, 2016
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    0
    Hi, Im looking to build a simple arduino circuit whereby a motion sensor turns a strip of LED lights on (one colour LED strip).

    i have been able to successfully do it with a single LED light with and without a bread board and resistor, but when I tried to hook it up to and LED strip it simply didn't light up.

    I then eliminated the motion sensing part of the circuit and again was able to light up a single LED but it doesn't light up the strip.

    I have connected it via the barrel port to the wall wart and I'm using Arduino UNO R3.

    Can anyone tell me what I need to do to get the LED strip to work with the arduino board. I'm using the gnd pin and pin 12 and its working fine to power a single LED, but what about a strip? Do I need a relay or a transistor?

    Perhaps someone could draw up a circuit I could copy?
     
  2. Dodgydave

    Distinguished Member

    Jun 22, 2012
    4,998
    745
    If your leds are in series they will need a bigger supply, can you post a picture of the led strip or model numbers.
     
  3. Ali Ashley

    Thread Starter New Member

    Mar 18, 2016
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    Hope this helps
     
  4. Dodgydave

    Distinguished Member

    Jun 22, 2012
    4,998
    745
    It clearly says 12V dc, so thats the supply you need.
     
  5. Ali Ashley

    Thread Starter New Member

    Mar 18, 2016
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    Well it works when I connect a 9V battery to the anode and cathode, I just dont know why it stops working when I try to power it through my arduino board. thank you for replying so fast
     
  6. Dodgydave

    Distinguished Member

    Jun 22, 2012
    4,998
    745
    Possibly because the Arduino is using a 5v supply, can you post a circuit diagram?
     
  7. MrSoftware

    Active Member

    Oct 29, 2013
    504
    124
    From memory; I believe the outputs on the Uno are not higher than 5v, and output current won't exceed 20-50mA depending on the voltage of the pin. So you're short on voltage, and looking at that LED strip I'm guessing it requires more than 20mA. I think you're going to need to use a transistor to power the LED strip, and use the Uno output to control the transistor. Maybe a logic level MOSFET. This one is overkill:

    http://www.kr4.us/n-channel-mosfet-60v-30a.html
     
  8. Ali Ashley

    Thread Starter New Member

    Mar 18, 2016
    4
    0
    Thank you so much this helped a lot. I'm assuming from its capacities I will only need one?
     
  9. MrSoftware

    Active Member

    Oct 29, 2013
    504
    124
    One would definitely do the trick.
     
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