void setup() {
  // put your setup code here, to run once:
#define fadeTime 3
Serial.begin(115200);
}
float bright;
long x;
long brightness (long x) {

long v;

bright =(x* 255)/(fadeTime* 1000);

v = (long) bright;

Serial.print ("v value is ");

Serial.print (v) ;

Serial.print('\n');

return v;


}

void loop() {
  // put your main code here, to run repeatedly:
x+=1;
Serial.println (x);
brightness(x*20);
delay(500);
}