I want to run a strip of 300 12V LEDs (Adafruit Neopixels with WS2811), with my Arduino. Is it safe to connect a follows, or is there some "separation" between voltage levels needed?

  • 5V voltage/out and ground (from converter 1) to Arduino Voltage-in and ground.
  • 12V voltage-out (from converter 2) to LED strip voltage-in.
  • 12V ground (from converter 2) to Arduino ground and LED strip ground.
  • Arduino data pin to LED strip data pin.
  • 1
    WS2811 are (usually) 5V LEDs. What LED strip exactly is it you intend to use? – Majenko Jun 20 '18 at 10:11
  • @Majenko Hmm strange! It's these: electrokit.com/en/product/rgb-led-slinga-20x-o30mm-2 – Anna Jun 20 '18 at 10:20
  • Ah right, not quite what I was expecting. Those are separate LED and driver chip arrangements, not the combined driver chip + LED SMD type you normally see. No problem. – Majenko Jun 20 '18 at 10:22

The signalling of those LEDs is 5V and the power supply 12V. Basically you have a 5V-powered chip with constant current sinks driving LED chains that are powered from 12V. The 5V power for the chip is created from the 12V power for the LEDs. So, you need to:

  • Provide +12V and GND to the chain of LEDs from a 12V power supply
  • Connect the data line to an Arduino
  • Connect the GND connection to the Arduino as well.

Nothing more is needed.

| improve this answer | |
  • Great! Thank you! As a beginner I was a bit worried about damaging the Arduino. – Anna Jun 20 '18 at 10:28
  • @Anna It's a common worry. As long as the 12V doesn't get connected to the Arduino it's fine. – Majenko Jun 20 '18 at 10:30

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