I am a complete Noob and thanks a lot of reading on this forum I have just finished my first Adrdiuno project 
I am using a 26PCBFA6D pressure sensor to test the depth of a river and then post the value to a mysql db on my website using a wavecom GPRS Modem and php script.
As the whole unit will be installed in a remote location I am powering the arduino with a 12v lead acid battery connected to a 12w solar panel. Thanks to the nightingale code I am able to put the arduino in and out of sleep mode for about 30 minutes until I read the sensor and post the data.
Thanks again for all the help.
Stuart
#include <avr/sleep.h>
#include <avr/wdt.h>
#include <SoftwareSerial.h>
#ifndef cbi //copied from nightingale:
#define cbi(sfr, bit) (_SFR_BYTE(sfr) &= ~_BV(bit))
#endif
#ifndef sbi
#define sbi(sfr, bit) (_SFR_BYTE(sfr) |= _BV(bit))
#endif
volatile boolean f_wdt=1;
int count = 191; //Set count high so dotest on startup
int pressureSignal = 0; // Pressure signal pin ANALOG-0
int val1 = 0; // Pressure value 1
int val2 = 0; // Pressure value 2
int val3 = 0; // Pressure value 3
float pressureValue = 0; // Average Pressure
int relayPin = 13; // 5v relay connected to DIGITAL-13
void setup() // copied from nightingale:
{
Serial.begin(9600);
cbi( SMCR,SE ); // sleep enable, power down mode
cbi( SMCR,SM0 ); // power down mode
sbi( SMCR,SM1 ); // power down mode
cbi( SMCR,SM2 ); // power down mode
setup_watchdog(9);
}
void loop()
{
if (f_wdt==1) { //copied from nightingale:
f_wdt=0;
if (count > 190) { //When count gets to 191 do pressure test
dotest();
}
else {
count++; //count +1
}
}
system_sleep();
}
void dotest() {
Serial.begin(9600);
digitalWrite(relayPin, HIGH); // Sets the relay on, switches on modem and pressure sensor
delay(12000);
val1 = 0;
val2 = 0;
val3 = 0;
pressureValue = 0;
pinMode(pressureSignal, INPUT); // Sets Analog pin to input
delay(900);
val1 = analogRead(pressureSignal); // Get value 1
delay(800);
val2 = analogRead(pressureSignal); // Get value 2
delay(700);
val3 = analogRead(pressureSignal); // Get value 3
delay(500);
pressureValue = ((val1+val2+val3)/3); // Get average value
Serial.print("AT+cpin=####\r\n"); // Input SIM pin
delay(3000);
Serial.print("at+wipcfg=1\r\n"); //start IP stack
delay(1000);
Serial.print("at+wipbr=1,6\r\n"); //open GPRS bearer
delay(1000);
Serial.print("at+wipbr=2,6,11,\"internet\"\r\n"); //set APN name of GPRS bearer
delay(1000);
Serial.print("at+wipbr=4,6,0\r\n"); //start GPRS bearer
delay(5000);
Serial.print("at+wipcreate=5,1,\"yourwebsite.com\",80,\"user\",\"password\"\r\n"); //connect to remote HTTP proxy server port 80 with authentication and some header fields
delay(5000);
Serial.print("at+wipopt=5,1,1,51\r\n"); //get size of the TCP send buffer size
delay(1000);
Serial.print("at+wipopt=5,1,2,53,6\r\n"); //set maximum number of redirects
delay(1000);
Serial.print("at+wipfile=5,1,1,\"http://yourwebsite.com/insertscript.php?data=");
Serial.print(pressureValue);
Serial.print("\"\r\n"); //HTTP GET method(not really what I should be using but it works:-) )
delay(5000);
digitalWrite(relayPin, LOW); // sets the relay off
count = 0; //set count to 0 to restart sleep loop
}
void system_sleep() { //copied from nightingale:
cbi(ADCSRA,ADEN); // switch Analog to Digitalconverter OFF
set_sleep_mode(SLEEP_MODE_PWR_DOWN); // sleep mode is set here
sleep_enable();
sleep_mode(); // System sleeps here
sleep_disable(); // System continues execution here when watchdog timed out
sbi(ADCSRA,ADEN); // switch Analog to Digitalconverter ON
}
void setup_watchdog(int ii) { //copied from nightingale:
byte bb;
int ww;
if (ii > 9 ) ii=9;
bb=ii & 7;
if (ii > 7) bb|= (1<<5);
bb|= (1<<WDCE);
ww=bb;
Serial.println(ww);
MCUSR &= ~(1<<WDRF);
// start timed sequence
WDTCSR |= (1<<WDCE) | (1<<WDE);
// set new watchdog timeout value
WDTCSR = bb;
WDTCSR |= _BV(WDIE);
}
ISR(WDT_vect) {
f_wdt=1; // set global flag
}