When running a lot of LEDs, it’s important to keep track of power usage. Individual LEDs don't get very hot or use tons of power, but they add up fast!
Each single RGB LED can draw up to 60mA from a 5V supply. That means a full meter can use nearly 2 Amps. That’s a peak rate, which assumes that all the LEDs are on at full brightness. If most of the LEDs are kept dim or off (as when animating patterns), the power usage can be 1/3 this or less.
As shown in the previous wiring diagram, connect ground to both your power supply and microcontroller. Then connect the 5V line from the power supply to the red wire on the LED strip.
Note the embossed polarity markings. Connect the red wire to the + terminal and the black wire to the - terminal.
- When creating longer runs, power should be split and applied every meter. If you try to power too many LEDs from just one end of the strip, they’ll start to “brown out” the further they are from the power supply.
- Strands can be powered from either end — “input” and “output” doesn’t apply to power, only the data signals from the microcontroller.
- If the 10 Amp power supply isn’t large enough for your project, a slightly modified ATX computer power supply can provide 30 Amps to power upwards of 500 pixels!
- Generally speaking, you should not try to power an LED strip from the Arduino’s 5V line. This is okay if just a few pixels are lit, but is not adequate for driving a full strand.
- For a standalone application (not USB connected to a computer), you can power the Arduino from the same regulated 5V supply as the LEDs — connect to the 5V pin on the Arduino, not Vin, and don’t use the DC jack on the Arduino.