sparkfun mosfet with led

Projects Programming
1

hi
i have this product

i pluged
pin12 to the input+
grd to input-
battery 3,7v to the battery input
and output to a led
i m using this code

int LedPin = 0;


void setup() {
  pinMode(12, OUTPUT);
  digitalWrite(LedPin ,HIGH); 
}

void loop() {
  digitalWrite(12, LOW); 
  delay(2000);
  digitalWrite(12, HIGH); 
  delay(2000);
}

the led is blinking but it is always on.
it becomes brighter when it takes digitalWrite HIGH

how can i turn it off?
Thank you

2

Do you have a current limiting resistor on the LED?

3

its a 3w led and i have 1k resistor in series from sparkfun output+ to led+
also 5k resistor between pin12 and sparfun input+

4

its working
i did a stupid polarity reverse somewhere between
thank

5

kostasgian:
its a 3w led and i have 1k resistor in series from sparkfun output+ to led+
also 5k resistor between pin12 and sparfun input+

Okay, glad to hear you have a resistor. Is the high value intentional? You know that you are running the LED on a tiny fraction of 3W? Also, you don't need the 5k resistor.

6

i change te resistor to 1k
can you explain me please what do you mean that im running the LED on a tiny fraction of 3W?

im using this LED http://grobotronics.com/high-power-led-3w-cold-white-emitter.html