Nodemcu

#include<SoftwareSerial.h>

#define led D5

SoftwareSerial mySerial(D7,D8);

char command;

String string;

boolean ledon = false;

void setup(){

Serial.begin(115200);

mySerial.begin(9600);

pinMode(led, OUTPUT);

}

void loop(){

if (mySerial.available() > 0)    {

string = "";

}

while(mySerial.available() > 0)

{

command = ((byte)mySerial.read());

if(command == ':')      {

break;

}

else    {

string += command;

}

delay(1);

}

if(string == "TO"){

ledOn();  ledon = true;

}

if(string =="TF"){

ledOff();

ledon = false;

Serial.println(string); //debug

}

if ((string.toInt()>=0)&&(string.toInt()<=255))  {

if (ledon==true)    {

digitalWrite(led, HIGH);

Serial.println(string); //debug

delay(10);

}

}

}

void ledOn(){

digitalWrite(led, HIGH);

delay(10);

}

void ledOff(){
digitalWrite(led, LOW);
delay(10);
}