light gate, shm pendulum not really working

So i am new here, i decided to make a light gate pendulum to measure gravity( shm method), but it wont work really, any ideas on what to do??? im using an i2c bus to connect the arduino unos but it just wont work no matter what i try and do

----------This is the master reader---------

#include <LiquidCrystal.h> // The LCD library
#include <Wire.h> // The i2c bus library

LiquidCrystal lcd(12, 11, 5, 4, 3, 2); //Pins used

void setup()
{
lcd.begin(16, 2);
Wire.begin(1);
}

void loop()
{
Wire.requestFrom(2, 96);

recieveEvent();
byte thisArray[2];
lcd.print(“The period =”);
lcd.print(thisArray[1]);
lcd.setCursor(0, 1);
lcd.print(“The value of g =”);
lcd.print(thisArray[2]);

}

void recieveEvent()
{
while(Wire.available() >0)
{
for(int p =0; p<2; p++)
{
byte thisArray[p] = Wire.read();
}
}
}


and now for the slave sender

#include <Wire.h>
#include <math.h>
int sensorpin = A0;

void setup()
{
pinMode(12, OUTPUT); // sets the LED at pin 12
double c = 4*(sq(PI)); // declaring the constant 4 pi^2
double L = 48;
Wire.begin(2); // initializes the i2c bus

}

void loop()
{
int val = analogRead(sensorpin);
digitalWrite(12, HIGH);
if(val > 200)
{
do
{
while(val < 200)
{
double T = (micros()/1000);
}
}

double T2 = sq(double T);
double g = (double c)*(double L)/T2;
delay(25);
byte Tp = (byte) T2;
byte gr = (byte) g;
byte test[2] = {Tp, gr};
Wire.write(test, 2);
}


Hi,
What won't work.
Have you tried at the Display end using dummy figures, and then sending dummy data from the pendulum end?
What is the reason for using two arduino?
What is the SHM method?

Also please repost your sketch, using code tags.. See section 7 http://forum.arduino.cc/index.php/topic,148850.0.html

Also , you are using D3 for the LED in the schematic, but D12 in the sketch.

Tom..... :slight_smile:

I haven't used wire, so I'm not sure, but I think you can only send integers, not floating numbers.
(I could be wrong...)