rscan.cpp

/*
 * Receiver for data of wireless weather sensors with RX868 and Raspberry Pi.
 *
 * Main program.
 */
#include <wiringPi.h>
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <string.h>
#include <iostream>
#include <fstream>
#include <time.h>
#include <string.h>
using namespace std;

static volatile int keepRunning = 1;

// String to recognize the sensor
//char idst[] = "001100000101\0";
char idst[] = "001100101110\0";

char sign[200];
char sipo = 0;
int temp = 0;
int rainl = 0;
int rainb = 0;
int logging = 0;
float temp_in = 0;
string temp_in_file = "";

int newbit(char bit);

//Create file stream myfile
ofstream myfile;
ifstream tempfile;

/*
 * Signal handler to catch Ctrl-C to terminate the program safely.
 */
void sigIntHandler(int dummy)
{
  keepRunning = 0;
}

/*
 * Thread to read the output of the receiver module.
 */
PI_THREAD(decoderThread)
{
  piHiPri(50);

  int x;
  int len = 0;
  int lo = 0;
  int hi = 0;
  int px = 0;

  while (keepRunning)
  {
    x = digitalRead(2);

    len++;
    if (0 == x)
    {
      lo++;
    }
    else
    {
      hi++;
    }

    if (x != px && 0 == x)
    {
      // slope high->low
      if (hi > 3 && hi < 12)
      {
        newbit('0');
      }
      else
      {
        newbit('1');
      }
      len = 1;
      lo = 1;
      hi = 0;
    }
    px = x;

    delayMicroseconds(200);
  }
}

// Not the best decoder, but working...
int newbit(char bit)
{
  if ((strlen(idst) - 1 > sipo) && (bit != idst[sipo]))
  {
    // Not the sensor -> reset
    sipo = 0;
    temp = 0;
    rainl = 0;
    rainb = 0;
    return 0;
  }
  sign[sipo] = bit;
  if (sipo > 13 && sipo < 24)
  {
    temp *= 2;
    if (bit == '1')
    {
      temp += 1;
    }
  }
  if (sipo > 23 && sipo < 32)
  {
    rainl *= 2;
    if (bit == '1')
    {
      rainl += 1;
    }
  }
  if (sipo > 31 && sipo < 40)
  {
    rainb *= 2;
    if (bit == '1')
    {
      rainb += 1;
    }
  }
  if (sipo > 86)
  {
    // Print the signal
    if (logging == 1)
    {
      printf("Signal found:\n%s\n  .   .   .   i   i ?ttttttttttrrrrrrrrRRRRRRRR   .   .   m   m   m   m   d   d   d   d   d   d\n", sign);
      float rtemp = (temp - 400) / 10.0;
      printf("Temp: %.1f°C\n", rtemp);
      float rrain = (rainb * 256 + rainl) * 0.3;
      printf("Rain: %.1f mm\n", rrain);
    }
    sipo = 0;
    temp = 0;
    rainl = 0;
    rainb = 0;
    //Get temp from w1 device
    try
    {
      tempfile.open("/sys/bus/w1/devices/28-00000a29b03b/w1_slave");
      if (tempfile.is_open())
      {
        getline(tempfile, temp_in_file);
        getline(tempfile, temp_in_file);
        tempfile.close();
      }
    }
    catch (const std::exception &e)
    {
      std::cerr << e.what() << '\n';
    }
    //Print raw signal to file
    myfile.open("/home/pi/tempRainPi/rawdata.txt");
    myfile << sign;
    myfile << ";";
    myfile << time(0);
    myfile << ";";
    myfile << temp_in_file.substr(29);
    myfile.close();

    return 0;
  }
  sipo++;
  return 0;
}

/*
 * MAIN
 */
int main()
{
  wiringPiSetup();
  /*
  BCM GPIO 27: DATA (IN) == WiPin 2
*/
  pinMode(2, INPUT);
  pullUpDnControl(2, PUD_DOWN);

  signal(SIGINT, sigIntHandler);

  piThreadCreate(decoderThread);

  while (keepRunning)
  {
    piLock(1);
    piUnlock(1);
    delay(200);
  }

  if (logging == 1)
  {
    printf("clean up and exit\n");
  }
}