Arduino: connect Arduino with ESP8266 aka ESP-01 - arduino

Question

I have an Arduino Mega 2560.
I want to connect it to ESP8266 aka ESP 01 module.
First i open and compile an empty sketch. When i start serial monitor, i write AT commands (like connect with WIFI) in serial monitor and i click on send button. In this case all works fine.
After I tested that the commands works properly , I want to write an Arduino sketch in which I implement the function to automatically send command without writing it in serial monitor.
For this purpose, i write this code:
#define SSID "test"
#define PASS "1111"
void connectWiFi() {
Serial.write(“AT+CWJAP=\"SSID\",\"PASS\"");
}
void setup() {
Serial.begin(9600);
connectWiFi();
}
void loop() {
}
When i try to execute the code in Serial monitor, it is printed only the string but the command does not work.
Why when i write this command in serial monitor works and when i try the code above, the command does not work?
Is there a way to pass and execute a command from arduino sketch? What is the problem in my code if is wrong?
Thanks in advance for response.
Sorry for my English.

Answer 1

Serial.write(...) makes arduino write through its serial ports (i.e. USB or pins 0 and 1). A better way to make Arduino send instructions directly to ESP is by defining "software serial" pins to communicate with ESP.
You'll need to include SoftwareSerial.h and use SoftwareSerial esp8266(2,3); for example to make pins 2 and 3 communicate serially with ESP.
Your code should look something like this:
#include <SoftwareSerial.h>
#define SSID "test"
#define PASS "1111"
SoftwareSerial esp8266(2,3);
void setup(){
Serial.begin(9600);
esp8266.begin(9600); //ensure this baudrate is similar to your ESP's
delay(500); //give it some time
esp8266.println(“AT+CWJAP=\"SSID\",\"PASS\""); //send to ESP this way
}
void loop(){
if(esp8266.available()){
while(esp8266.available()){
Serial.write(esp8266.read()); //make serial monitor print what ESP sends
}
}
}
You can also refer to this example for further detail