controlling a super-bright led 3,5 watt

Using Arduino LEDs and Multiplexing
#1

do you think this may work?

    // Esempio 01: accendi il led appena è premuto il pulsante  
      
    #define LED 7                // LED connected to the digital pin 7  
    #define BUTTON 9              // pin input button  
    int  val = 0;                 // status input   pin
      
    void setup() {  
      pinMode(LED, OUTPUT);       //  pin as output  
      pinMode(BUTTON, INPUT);     // pin as input  
    }  
      
    void loop() {  
      val = digitalRead(BUTTON);  // read the pin value and save it
      
      // control that input is HIGH (button pressed)  
      if (val == HIGH) {  
        digitalWrite(LED, HIGH);  // led  turn on
      }  
      else {  
        digitalWrite(LED, LOW);   // led  turn off
      }  
    }
#2

If you want to start a fire, then yes.

A few observations:

  • The 2N2222 is not good for 1A
  • Why is there a 10k resistor in the current return path
  • If the LED gets warm (and it will), it's forward voltage will go down --> more current --> gets even warmer ... etc

Constant current LED drivers are the way to go. Either get one on ebay for almost no money or build one (most likely more expensive).

#3

madworm: * The 2N2222 is not good for 1A

um.. you are right this is the specs of the 2N2222T i bought:

Manufacturer Part No: 2N2222A ROHS: Yes Current Rating: 0.8A Voltage Rated: 40V Transistor Type: NPN Features: General Purpose Package: TO-92

so if i use a resistor that limit the ampere to 0,7A it should be fine.. (altought i will lose a bit of light), or i may just use another transistor model that support 1A (as the 2SC1384)

  • Why is there a 10k resistor in the current return path

i corrected the resistors position

  • If the LED gets warm (and it will), it's forward voltage will go down --> more current --> gets even warmer ... etc

the LED will not be permanently ON, it will be installed on a replica gun to simulate the fire of the shot

i also changed the power supply of the led, now i connected it directly to the arduino 5volt

#4

You are running a 3.5W LED through a 2W resistor? I suppose that would be OK for short bursts.

#5