collar/collar.cpp

#include <SPI.h>
#include <LoRa.h>
#include <TinyGPS++.h>
#include <SoftwareSerial.h>

#include "pb_common.h"
#include "pb.h"
#include "pb_encode.h"

#include "gateway/message.pb.h"

unsigned long previousMillis = 0;
const long interval = 5000;
float lat = 0;
float lng = 0;

bool sending = false;

TinyGPSPlus gps;

SoftwareSerial ss(6, 7);

typedef struct lora_status_s {
  int sleep;
} lora_status_t;

static lora_status_t lora_status;

void transmitLora() {
  // Encode as protobuf packet
  if (lat && lng) {
    uint8_t buffer[50] = {0};
    Fenceless_CollarResponse m = Fenceless_CollarResponse_init_zero;
    pb_ostream_t stream = pb_ostream_from_buffer(buffer, sizeof(buffer));
    m.loc.x = lat;
    m.loc.y = lng;

    int status = pb_encode(&stream, Fenceless_CollarResponse_fields, &m);

    if (!status) {
      Serial.println("Failed to encode");  
    }

    Serial.print("Sending packet Lat / Long: ");
    Serial.println(lat);
    Serial.println(lng);

    // send packet

    LoRa.beginPacket();
    LoRa.print((char *) buffer);
    LoRa.endPacket();

  }
}
void updateGPS() {
  // Gather GPS data
  if (gps.location.isValid()) {
    lat = gps.location.lat();
    lng = gps.location.lng(); 
  } else {
    lat = 0;
    lng = 0;  
  }
}
ISR(TIMER1_OVF_vect) { 
  // handle timer overflow interrupt at 1 per second
  updateGPS();
  if(!gps.location.isValid()) {
    Serial.println("Seeking GPS");
  }
  if(sending && gps.location.isValid()) {
    if(lora_status.sleep) {
    }
    transmitLora();
  }
}
void initialize_timer() {
  TCCR1A = 0;
  TCCR1B = 0;
  TCNT1 = 34286; // timer preload
  TCCR1B |= (1<<CS12); // prescale: 256 bits
  TIMSK1 |= (1<<TOIE1); // overflow interrupt
  interrupts();
}
void setup() {
  Serial.begin(9600);
  ss.begin(9600);

  while (!Serial);

  Serial.println("LoRa Transceiver");

  if (!LoRa.begin(915E6)) {
    Serial.println("Starting LoRa failed!");
    while (1);
  }
  LoRa.setSpreadingFactor(7);

  lora_status.sleep = 1;
  //lora.sleep();

  initialize_timer();
}

void loop() {
  /* Get user input
  */
  if(Serial.available()) {
    char n = Serial.read();
    if(n=='p') {
      sending ? Serial.println("Sending is: disabled") : Serial.println("Sending is: enabled");
      sending = !sending;
    } else {
      Serial.println("Type the letter 'p' to toggle sending");
    }
  }
  /* GPS data recieved */
  while (ss.available() > 0) {
    gps.encode(ss.read());
  }
  /* Lora data recieved */
  int packetSize = LoRa.parsePacket();
  if (packetSize) {
    Serial.print("Received Packet: ");
    while (LoRa.available()) {
      Serial.print((char) LoRa.read());  
    }
    Serial.println();
  }
}