Hi I was thinking maybe use a relay board with 8 relay to controll some LED but I wonder if that is something better to use?
is going to be 22 LED to controll so I have to have a relay of somekind so ATMega326P can send to say turn on/off the power to the LED.
I just afraid the relay is going to make to much sound.
A logic level MOSFET per LED may be the solution, but hard to be sure without knowing more about your LEDs and why they need a relay.
If the 22 LEDs are individually controlled then 22 MOSFETs would do it, however 1 MOSFET can easily drive 22 LEDs. I am going to assume you want to control each separately, this can be accomplished by using a simple HCMOS shift registers such as the 74HC585 and depending on how you connect it you can light them all with just a few pins on your Arduino. How fast you want to cycle them has a big impact on your hardware design. There is no way a complete answer can be given without more details. Consider doing a Schematic and post that. See if you can find a good book on elementary electronics, the refresher will help you a lot. Good Luck & Have Fun! Gil
Thanks for the replay.
Well my project is quite basic but not easy to write it down in english (My first lang is swedish).
I have 15 RGB LED and is two group with 7 in each group and one alone. I also have a group of 7 white LED.
So in a group I connect each LED color to another LED color. Example Digital 1 = turn group 1 to RED Digital 2 = turn group 1 to GREEN Digital 3 = turn group 1 to BLUE
Digital 4 = turn group 2 to RED Digital 5 = turn group 2 to GREEN Digital 6 = turn group 2 to BLUE
Digital 7 = turn single RGB LED to RED Digital 8 = turn single RGB LED to GREEN Digital 9 = turn single RGB LED to BLUE
Digital 10 = turn Group 3 LED WHITE
I guess the only that does not need any relay or something is the single RGB LED but the other have to have something.
I hope I make it a little easy to understand what I going to do.
I have work with Arduino and LED before but not so many :)
the refresher will help you a lot.
If they've never studied electronics then there is nothing to "refresh" is there ?