Sending arduino signal to another arduino I'm working on a project which consists of 2 different function. since the arduino only can do 1 function so i decide to use 2 arduino instead. my idea is 1st arduino will give a output and the sketch on the 2nd arduino will run Only after the input given from the 1st arduino. So can i make a digital output which will be send to the input of 2nd arduino? 

if it could be, i already make a code for the 2nd arduino which will be run after there was an input from the 1t arduino: 

//define the input/output pins
#define FLOAT_SWITCH_PIN 2
#define PUMP_1_PIN 4
#define LED_PIN 7
#define output1starduino 3
//setup runs once
void setup()
{


  pinMode(FLOAT_SWITCH_PIN, INPUT_PULLUP);
  pinMode(output1starduino, INPUT_PULLUP);

  //setup output pins for relays/pumping station and LED board
  pinMode(PUMP_1_PIN, OUTPUT);
  pinMode(LED_PIN, OUTPUT);

}

//loop() runs indefinitely 
void loop()
{

  if(digitalRead(output1starduino) == HIGH) // output from 1st arduino
  if(digitalRead(FLOAT_SWITCH_PIN) == LOW)
  {
     digitalWrite(PUMP_1_PIN, HIGH); //turn on the pump
     digitalWrite(LED_PIN, HIGH);    //turn on the LED
  }


  {
     digitalWrite(PUMP_1_PIN, LOW); //turn off the pump
     digitalWrite(LED_PIN, LOW);    //turn off the LED
  }
} 


as i write on the line, the "output1starduino" which an digital output from the first arduino. Is this the right way for me to write if i want the program here to run only right after the output from 1st arduino given?

*** this is the code of first arduino which will be sent to the 2nd arduino 

int motorPin = 3; // motor pengisian (m1)
int blinkPin = 4; //
int motor1 = 5;// motor pembuangan
int motorklorin = 6;// pam topap 
int switch1 = 2;// switch float
int indicator1 = 7; 
int indicator2 = 8;
int indicator3 = 9;
int output1starduino = 2;
void setup()
{
  pinMode(motorPin, OUTPUT); 
  pinMode(blinkPin, OUTPUT); // penujuk fasa pengisian
  pinMode(motor1, OUTPUT);
  pinMode(motorklorin, OUTPUT); // MOTOR UNTUK topap
  pinMode(switch1, INPUT_PULLUP);// PELAMPONG
  pinMode(indicator1, OUTPUT);// lampu penunjuk fasa pembuangan
  pinMode(indicator2, OUTPUT);// lampu penunjuk topap
  pinMode(indicator3, OUTPUT);// lampu menunggu
  pinMode(output1starduino, OUTPUT); // KELUARAN KE ARDUINO 2
}


void loop()

{
  digitalWrite(motorPin, HIGH); // turn on the motor
  digitalWrite(blinkPin, HIGH); // turn on the LED
  digitalWrite(motor1, HIGH);// on lampu
  digitalWrite(motorklorin,HIGH);
  delay(1000);        // 

  digitalWrite(motorPin, HIGH);  // 
  digitalWrite(blinkPin, HIGH);  // penunjuk fasa pembuangan hidup
  digitalWrite(motor1, LOW);// motor pembuangan jalan (air start turun/pembuangan
  digitalWrite(motorklorin,HIGH);
  delay(180000);        //tempoh pembuangan 

  digitalWrite(motorPin, LOW); // turn on the motor (motorisi balik air jalan/pengisian
  digitalWrite(blinkPin, LOW); // 
  digitalWrite(motor1, HIGH);// filling motor on
  digitalWrite(indicator1, HIGH); //indicator
  delay(150000);        // duration filling


  digitalWrite(motorPin, HIGH);  // turn off the motor
  digitalWrite(blinkPin,HIGH);  // turn off the LED
  digitalWrite(motor1, HIGH);// 
  digitalWrite(output1starduino, HIGH);
  delay(100000);        // multiply by 60000 to translate minutes to milliseconds
  }
An arduino may not be as fast as a PC or phone, but it is VERY fast indeed (16,000,000 operations /sec). Unless the code for arduino #1 is incredibly complex, the one arduino should be able to do it all on its own. 
P.S. Please post the code for Arduino #1