Sending arduino signal to another arduino

Question

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
 }

• Juraj: One arduino can do many functions. My asks data over modbus, calculates and sets pwm, makes some http requests, serves web pages from SD card and ajax requests, handles 4 relays, reads a current sensor and a temperature sensors, lights leds, checks a button, calculates consumption, writes events to eeprom, csv log and consumption stats to SC card... github.com/jandrassy/Regulator/tree/master/Regulator

Answer 1

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

• Asrul Asyraff: i just edited the post.. feel free to give a check!
• user35284: The Arduino should easily be able to do that on its own.

Answer 2

Combine them like this - I moved the duplicate pins to other pins

//define the input/output pins
#define FLOAT_SWITCH_PIN 2
#define PUMP_1_PIN 4
#define LED_PIN 7
#define output1starduino 3
byte motorPin = 11; // motor pengisian (m1)
byte blinkPin = 12; //
byte motor1 = 5;// motor pembuangan
byte motorklorin = 6;// pam topap 
byte switch1 = 2;// switch float
byte indicator1 = 13; 
byte indicator2 = 8;
byte indicator3 = 9;
byte output1starduino = 10;
//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);
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
}
//loop() runs indefinitely 
void loop()
{
if(digitalRead(output1starduino) == HIGH) // output from 1st Arduino
{
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
}
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
 }
} 

• CrossRoads: Duplicate pins might need some more cleanup.
• CrossRoads: Why the downvote?