#include <SoftwareSerial.h>

const String phone = "0786701940";     // Thay so cua ban vao day
const int PWR_KEY =  9;                          // Chan so 9 arduino uno dung lam chan dieu khien bat tat module sim800C
const int RELAY =  12;                              // Chan so 12 arduino uno dung lam chan dieu khien dong/cat Relay de On/Off den

const int rxpin = 4;
const int txpin = 3;
char receivedChar;
boolean newData = false;
SoftwareSerial myserial(rxpin, txpin);

void Gsm_Power_On();                                            // Bat module Sim800C
void Gsm_Init();                                                       // Cau hinh Module Sim800C
void Gsm_MakeCall(String phone);

void recvOneChar() {
    if (myserial.available() > 0) {
        receivedChar = myserial.read();
        newData = true;
    }
}

void showNewData() {
    if (newData == true) {
        Serial.print("This just in ... ");
        Serial.println(receivedChar);
        newData = false;
    }
}

void setup() {
  digitalWrite(RELAY, LOW);               // Khai bao chan  de dieu khien dong cat RELAY
  pinMode(RELAY, OUTPUT);

  digitalWrite(PWR_KEY, LOW);         // Khai bao chan PWR_KEY de dieu khien bat bat module Sim800C
  pinMode(PWR_KEY, OUTPUT);

  delay(1000);
  Gsm_Power_On();                                      // Bat Module Sim800C                                              // Đợi module sim kiểm tra kết nối mạng GSM

  myserial.begin(9600);
  Serial.begin(9600);
  myserial.println("AT+CFUN=1");
  //myserial.println("AT+CREG=1");
  //myserial.println("AT+COPS=0,2");

  Gsm_Init();
  Gsm_MakeCall(phone);
}

void loop() {                                                                    // tre 1s
  recvOneChar();
  showNewData();
  Serial.println("looping...");
  delay(1000);
  //if (millis() % 15000 == 0) {
  //  Serial.println("calling... ");
                                                  // delay 5s
  //}
}

void Gsm_Power_On()
{
  digitalWrite(PWR_KEY, HIGH);                // Du chan PWR_KEY len cao it nhat 1s
  delay(1500);                                            // o day ta de 1,5s
  digitalWrite(PWR_KEY, LOW);                  // Du chan PWR_KEY xuong thap
  delay(100);                                              // cac ban xem trong Hardware designed sim800C de hieu ro hon
}

void Gsm_MakeCall(String phone)
{
  myserial.println("ATD" + phone + ";");         // Goi dien
  delay(10000);                                        // Sau 10s
  myserial.println("ATH");                              // Ngat cuoc goi
  delay(2000);
}

void Gsm_Init()
{
  myserial.println("ATE0");                            // Tat che do phan hoi (Echo mode)
  delay(2000);
  myserial.println("AT+IPR=9600");              // Dat toc do truyen nhan du lieu 9600 bps
  delay(2000);
  myserial.println("AT+CMGF=1");                // Chon che do TEXT Mode
  delay(2000);
  myserial.println("AT+CLIP=1");                  // Hien thi thong tin nguoi goi den
  delay(2000);
  myserial.println("AT+CNMI=2,2");              // Hien thi truc tiep noi dung tin nhan
  delay(2000);
}