Like I said before:
(2) You use uninitialized variables.
This line:
P = (duration*2*Pi)/T;
depends upon the value of duration, which probably defaults to zero when you don't provide a value. Of course this results in P being zero. What do you expect?
Oh, and just credit me as vaj4088. Thanks
Oh, and the documentation at https://www.arduino.cc/en/Reference/Cos
could be clearer, but it says that cos(...) takes a float - in radians - and returns a double. There is nothing that should be assumed about taking P and putting it in double quotes. There is nothing about degrees.
I have reason with my variable,
I choose P for Phase
ang for angle
T for Period (length of 1 period in ms)
duration for input (ms)
then I put in double cause I thinking it count in degree at the moment,
the formula
P = (duration*2*Pi)/T;
the formula is correct, based
P = (duration*360*Pi)/(180*T) // this formulas convert degree to rad
Actually I have duration in setup stage
but the result still 0 because I forgot to put that in loop stage.
#include <LiquidCrystal.h>
#define radians(deg) ((deg)*DEG_TO_RAD)
#define degrees(rad) ((rad)*RAD_TO_DEG)
int pin = 7;
double Hz = 50;
double T = (1000/Hz);
const float Pi = 3.14159;
double P;
double PF;
double duration;
LiquidCrystal lcd(12, 11, 5, 4, 10, 9);
void setup()
{
lcd.begin(17, 3);
pinMode(pin, INPUT);
P = (duration*2*Pi)/T;
PF = cos(P);
}
void loop()
{
P = (duration*2*Pi)/T;
PF = cos(P);
lcd.setCursor(0, 0);
duration = pulseIn(pin, HIGH);
lcd.print(PF);
lcd.setCursor(0, 1);
lcd.print(P);
lcd.setCursor(7, 0);
lcd.print(T);
lcd.setCursor(7, 3);
lcd.print(duration);
}
Its work
