hi peter. thanks for replying. actually there is an add on i made for my project. which is the power failure (failure LED). And for the arduino to be able to know which LED's are failure, there must be no current going trough the Collecter of Q1. If it happen the only way for the current to flow is to go through D11 and Q3. Therefore, a signal can be send back to the arduino and i will add an LCD to show what's goin' on at the output (LED failure). For this schematic, the connection of LED failure only exist at the 1st group of LED's. That's why i want u guys opinion.. For the cases for tuning up resistor, i have done it. and im using crystal White 006 (3v, 5mm) led's.