Mains Failure Detector

1/*  
2
3GPRS Shield with SIM900
4
5Connections:
6Arduino UNO  pin 2 to Vin
7Arduino UNO pin 7 to Shield TXD
8Arduino UNO pin 8 to Shield RXD
9Arduino  UNO pin 9 to Shield pin 9 (shield ON/OFF)
10Arduino UNO GND to Shield GND
11
12*/
13
14#include  <SoftwareSerial.h>
15
16// Configure software serial port
17SoftwareSerial SIM900(7,  8); 
18
19//Variable to save incoming SMS characters
20char incoming_char=0;
21//Allarm  status
22byte allarmSent = LOW;
23
24void setup() {
25  // Switch on the GSM  shild
26  pinMode(9,OUTPUT);
27  digitalWrite(9, HIGH);
28  delay(2000);
29  digitalWrite(9, LOW);
30  delay(5000);
31  // Set pin 2 as input for Vin detection
32  pinMode(2,INPUT);
33  // Arduino communicates with SIM900 GSM shield at a baud  rate of 19200
34  SIM900.begin(19200);
35  // Give time to GSM shield to log on  to network
36  delay(30000);
37  // AT command to set SIM900 to SMS mode
38  SIM900.print("AT+CMGF=1\
");  
39  delay(100);
40  sendSMSready();
41  // Set module to send SMS data to serial  out upon receipt 
42  // SIM900.print("AT+CNMI=2,2,0,0,0\
");
43  // delay(100);
44}
45
46void  loop()
47{
48  // Display any text that the GSM shield sends out on the serial  monitor
49  if(SIM900.available() >0) {
50    //Get the character from the cellular  serial port
51    incoming_char=SIM900.read();
52    //Print the incoming character  to the terminal
53    Serial.print(incoming_char);
54  }
55  while (digitalRead(2)  == HIGH) {}
56  if(digitalRead(2) == LOW && allarmSent == LOW) {
57    // whait  1" more and send message if pin 2 is already LOW
58    delay(1000);
59    if(digitalRead(2)  == LOW) sendSMSallarm();
60  }
61  while (digitalRead(2) == LOW) {}
62  if(digitalRead(2)  == HIGH && allarmSent == HIGH) sendSMSallarmOFF();
63}
64
65void sendSMSallarm()
66{
67  // Set recipient's mobile number in international format
68  SIM900.println("AT  + CMGS = \\"+XXXXXXXXXXXX\\""); 
69  delay(100);
70  // Set SMS message
71  SIM900.println("*** MANCANZA TENSIONE RETE ***");
72  delay(100);
73  // End  AT command with a ^Z, ASCII code 26
74  SIM900.println((char)26);
75  delay(100);
76  SIM900.println();
77  // Give module time to send SMS
78  delay(5000);
79  allarmSent  = HIGH;
80}
81
82void sendSMSallarmOFF()
83{
84  // Set recipient's mobile  number in international format
85  SIM900.println("AT + CMGS = \\"+XXXXXXXXXXXX\\"");  
86  delay(100);
87  // Set SMS message
88  SIM900.println("*** TENSIONE RETE  OK ***");
89  delay(100);
90  // End AT command with a ^Z, ASCII code 26
91  SIM900.println((char)26);
92  delay(100);
93  SIM900.println();
94  // Give  module time to send SMS
95  delay(5000);
96  allarmSent = LOW;
97}
98
99void  sendSMSready()
100{
101  // Set recipient's mobile number in international format
102  SIM900.println("AT + CMGS = \\"+XXXXXXXXXXXX\\""); 
103  delay(100);
104  //  Set SMS message
105  SIM900.println("*** SISTEMA CONNESSO ***");
106  delay(100);
107  // End AT command with a ^Z, ASCII code 26
108  SIM900.println((char)26);
109  delay(100);
110  SIM900.println();
111  // Give module time to send SMS
112  delay(5000);
113}
114