Arduino vs Wemos Fan control I have a working fan control with the correct wiring that works with arduino.

I would like to change the arduino with a Wemos D1 mini board. 

When I hook everything up. The fans are not activated. 

The fan is driven by a 12v charger. And the irf540n cicruit powers that. They just share a common ground and the pwm pin D5

Is there something I need to know about the difference in both of them? 

Below is the code, I've changed D5 in the code to 14. 

Still nothing seems to work.

    #define fan D5

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  Serial.println("start");
  pinMode(fan, OUTPUT);

  digitalWrite(fan, LOW);
}

void loop() {
  // put your main code here, to run repeatedly:
  delay(1000);
  digitalWrite(fan, HIGH);

  delay(1000);
  digitalWrite(fan, LOW);
}
The IRF540 is not suitable to be controlled by a 3.3V device because it has a gate-source-threshold voltage of 2-4V (that's the voltage at which the mosfet starts to conduct, but you need to be above that voltage). While this worked at 5V logic level on the arduino, the 3.3V are not enough to make the mosfet switch entirely.

A suitable mosfet has a threshold voltage below 1V. Also for a fan, you eon't need a big mosfet rated for 30A, a tiny one will do it.