Powering 36 LED´s on Arduino Mega 2560


I´d like to know how to power my 36 LED´s and roughly 25 Switches. I know that the Mega has 5 GND and 5 x5V Pins but is the Arduino capable of running them all? I heard about getting External Power and im going to this if this methond doesn´t work but on this Site https://create.arduino.cc/projecthub/david-hansel/arduino-altair-8800-simulator-3594a6?f=1 (The Project i want to do). And this Person somehow managed it to do. But how? I´m fairly new to Electronic so sorry for this dumb question. Thanks

Yes, that's no problem. You just have to watch the current drawn by the 36 LEDs does not exceed the maximum current that the atmega2560 can handle. With modern LEDs, 5mA per led is probably enough to make them bright enough, which is 180mA in total. So choose series LEDs to limit the current to around 5mA.

“So choose series LEDs to limit the current to around 5mA.”
Maybe should read:
So choose series resistors to limit the current to around 5mA.


Yes, thanks larryd

The 2560 itself can handle 800 mA with its 4 VCC and 4 Gnd pins, 200mA per pin.

Must pay attention to the current per Port of the datasheet. See the notes after table 31.1.