nicoskaralis:
I'm trying to build a wireless RGB led controller with a Wemos D1 mini, with this tutorial
A TIP31 with 1k base resistor to drive a LED strip is not a smart move.
Driving that with a 3.3volt pin is even worse.
A TIP120 with 330ohm base resistor could be much better (more light).
A mosfet is even better, assuming you can find one with low enough Vgs(th).
Leo..