#include "fan speeeed.h" int fan_speed(float voltage_value){ float fan_speed; float t = 0; float past_time = 0; float start_time = 0; int old_value = 0; int f; if (voltage_value > 300 && old_value < 300){ start_time = millis(); t =(start_time - past_time); paste_time = start_time; } voltage_value = old_value; f = ((1/t)*1000); fan_speed = (f*60)/2; return fan_speed; }