Hello, I'm doing a project where I'm trying to power some powerful leds from the digital pins, however I can't seem to draw enough power from them. Is there any way to draw as much power from the digital pins as I can from the 5v pin? I'm using a 12v 1a power supply. Thanks
You should not draw more than 20 mA (and never more than 40 mA) from an output pin, or you will damage the Arduino.
Pins are for controlling other circuits, and generally are not for supplying power (other than one LED, for example). External circuits and power supplies are absolutely required for high power loads.
You can only directly power a couple of regular little LEDs. The I/O pins are signals and they are not intended to "power" anything. The "absolute maximum" current allowed is 40mA (0.040 Amps) per pin and 200mA total. 20mA or less is generally recommended.
High power LEDs are driven with a [[u]special constant-current power supply./[/u]. There are LED power supplies that can be switched on/off or dimmed with a low-power control signal. However, the commercial industry standard for dimming is 10V PWM so you still need a transistor or MOSFET to use them with an Arduino.
Regular LEDs use a resistor to control/limit current. It's possible to use the same method with a high-power LED and a simple transistor/MOSFET, but you need a power-resistor and the resistor may dissipate more power than the LED so it's inefficient and it's rarely done.
"some powerful LEDs" can be anything. Even a 5meter addressable LED strip that can be controlled directly from a pin.
Post a link to the LED if you want correct answers. Leo..