/* Sender-a1
++++++++++ The BackShed Water Level Meter ++++++++
Incorporating suggestions from many BackShed Contributers
Avoid using NewPing Library
Introduce Sleep Function
Use direct register management in lieu of any sleep library
*/

#define RX_PIN 3
#define TX_PIN 4
#define LOW_POWER_PIN 5
#define TRIGGER 7
#define ECHO 8
#define TooLong 15000

#include <SoftwareSerial.h>

//int max_distance = 250;
//int min_distance = 0;
//int duration;
int min_time = 1130;
SoftwareSerial mySerial(RX_PIN, TX_PIN);


void setup() {
Serial.begin(1200);
mySerial.begin(1200);
pinMode(LOW_POWER_PIN, OUTPUT);
pinMode(TRIGGER, OUTPUT);
pinMode(ECHO, INPUT);

// The attachInterrupt is only required if there is need to force wake status.
//attachInterrupt(0, digitalInterrupt, FALLING); //interrupt for waking up

// Setup Watchdog Timer
WDTCSR = (24);
WDTCSR = (33); // 8 Seconds sleep
WDTCSR |= (1<<6);
// Disable ADC
ADCSRA &= ~(1 << 7);
// Enable SLEEP
SMCR |= (1 << 2); // power down mode
SMCR |= 1; // enable sleep
}

void loop() {
//delay(2000); // B
digitalWrite(LOW_POWER_PIN, HIGH); // Power up the MOSFET
// as per Grogster
delay(500);
int count = 0;
unsigned long StartTime = millis();
unsigned long ElapsedTime;

mySerial.println("S");

do{
long int duration = aping(); // Do the depth Sounding
if(duration>0){
mySerial.println(duration);
delay(500);
count++;
unsigned long CurrentTime = millis();
ElapsedTime = CurrentTime - StartTime;
}
}
while(count != 10 && ElapsedTime < TooLong);

mySerial.println("E");

// Close down power
digitalWrite(LOW_POWER_PIN, LOW); // Power Down MOSFET
delay(500); // May need to increase if no sleep
// Stop current leakage from floating pins in to HC12
// as per ryanm
digitalWrite(RX_PIN, LOW);
digitalWrite(TX_PIN, LOW);
delay(150); // May need to increase if sleep truncated
// Put 328P to sleep
sleepLoop(1);
//delay(8000);
//delay(2000); // A
}

long int aping(){
digitalWrite(TRIGGER, LOW);
delayMicroseconds(2);
digitalWrite(TRIGGER, HIGH);
delayMicroseconds(10);
digitalWrite(TRIGGER, LOW);
long int xx = pulseIn(ECHO, HIGH);
if(xx > min_time){
return xx;
} else {
//Serial.println("Too Close");
}
}

void sleepLoop(int loopNum){ // as per Keith Darrah
// Sleep duration = 8 * loopNum seconds
for(int i=0; i<loopNum; i++){
// BOD Disable
MCUCR |= (3 << 5);
MCUCR = (MCUCR & ~(1 << 5)) | (1 << 6);
__asm__ __volatile__("sleep"); // go to sleep
}
}

//void digitalInterrupt() { //support digital input interrupt
//}

ISR(WDT_vect){ // support watchdog timer
}