Hi,
sorry for my english.
i need to control 33 Separate leds, because i need 33 leds==> i need 33 digital outputs, so i will go with the arduino mega.
Each one of the leds Consume 20mA so i need a 1A power supply.
now, what is the best way to connect the digital output to the led?
transistor? if yes , this is the circuit i need ?(for only one of the led)
so,
-R1=(VCC-Vled)/20m
-what is the best transistor for this? logic level n-fet?
Try this instead - instead of wiring up a bunch of transistors, use a MAX7219 to control them all.
You just need the MAX7219, 10uF cap, 0.1u cap, and a resistor around 10K.
Three pins from the Arduino to send data to the MAX7219 to turn the LEDs on & off.
I even offer a card to make it really easy:
http://www.crossroadsfencing.com/BobuinoRev17/
Hello, I'm starting with arduino, I want to connect 3 series of 10 power LEDs, 3.4v and 500ma and dimmear them through bluethooth but I have searched and I do not really find that I need to do that, the most that I could control are just 3 leds using the outputs 9,10,11 of Arduino UNO, is for an aquarium lamp, thanks I hope I can help
As I replied in an earlier PM:
High power LEDs like that need current-controlled drivers to keep them from overheating and drawing even more current & then burning up, such as this one
I think sparkfun.com has high current drivers, if not I can design a board that can be Arduino controlled.
nirne:
Hi,
sorry for my english.i need to control 33 Separate leds, because i need 33 leds==> i need 33 digital outputs, so i will go with the arduino mega.
Each one of the leds Consume 20mA so i need a 1A power supply.
now, what is the best way to connect the digital output to the led?
transistor? if yes , this is the circuit i need ?(for only one of the led)
so,
-R1=(VCC-Vled)/20m
-what is the best transistor for this? logic level n-fet?
Your setup is not advised because the maximum current you can draw from the Mega is 800ma in total before you start to damage the board.
You could be pushing your mega to his max with that current draw form 33 pins. See:
http://playground.arduino.cc/Main/ArduinoPinCurrentLimitations
I would power and control the leds using 5x TLC5917IN LED Driver. Then you can power the leds with an external power source.
Sorry I was not totally paying attention, but maybe Crossroads can shed some more light on this matter.
