Based on this question on the Adafruit forum for Nth-Light Narrow LED Flexible Strip Light (https://www.adafruit.com/product/3683) and the image below is it safe to connect from the 12v source + a wire to the Vin (orange wire) or it is better to connect to another DC barrel?

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1 Answer 1


If your 12V power supply has enough current to drive your LED strip at its maximum power, plus the Arduino's power supply, plus about 10-20% of "wiggle room" you should be fine. As the LED strip draws spikes of current the voltage from your power supply might bounce around a little, but the Arduino's voltage regulator would be fine with as little as 7.5V input.

Note that your Arduino's voltage regulator will get hot if you use much current from the Ardunio's 5V rails, since it has to regulate 12V down to 5V and the linear regulator on the Arduino converts the extra voltage to heat.

  • Thanks. any alternative solution in order to avoid the heat issue? The LED is intend to be in a close space.
    – lroca
    Jun 28, 2019 at 17:30
  • If you aren't driving much load from the Arduino's 5V pin it might not be a problem. Total power converted to heat will be ≈total_current • (12V-5V)
    – Duncan C
    Jun 28, 2019 at 19:23
  • If you're really sensitive to heat, drive the Arduino with a separate switching 5V supply fed into the USB port. That bypasses it's regulator entirely
    – Duncan C
    Jun 28, 2019 at 19:24

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