Led Driver/Controller for 3.3v & 5v circuit
To invert your signal, use another transistor.







simulate this circuit &ndash; Schematic created using CircuitLab

Any of the BJTs will work. I'm personally partial to the 2N3904, but that's habit more than anything. Of the MOSFETs, I'd recommend first the IRF520, then the RFP70N06, and the IRF510 last, although any of them will work. If you use the IRF510, a heat sink on each one is a very good idea. With the IRF520, the worst-case power dissipation (LED on 100%) will be about 1 watt, so a heat sink is a good idea but not required. 

The smoothing circuit link is worrying unnecessarily about response time.