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Сенсор давления на BMP-180

Добавлено: 12 май 2019, 14:37
MEHANICUS
После проблемы с повторением сенсора давления из раздела "Сборка",порывшись на англоязычном источнике,нашел эту ветку https://forum.mysensors.org/topic/4807/ ... -sensor/19.Немного переделал под себя и дело пошло.Но был недоволен тем,что давление отображалось в Паскалях.Так как сам не очень силен в кодинге-обратился к ребятам в Телеграмм -благодаря их стараниям появился модифицированный код.Все что нужно в нем сделать -это проставить свою высоту над уровнем моря :
const float ALTITUDE = 299; // <-- adapt this value to your own location's altitude.
Вот скетч :

Код: Выделить всё

// Enable debug prints to serial monitor
#define MY_DEBUG

// Enable and select radio type attached
#define MY_RADIO_NRF24
//#define MY_RADIO_RFM69

#include <SPI.h>
#include <MySensors.h>
#include <Wire.h>
#include <Adafruit_BMP085.h>

#define BARO_CHILD 0
#define TEMP_CHILD 1

float pressure_mm;
const float ALTITUDE = 299; // <-- adapt this value to your own location's altitude.
float pressure;
float temperature;

// Sleep time between reads (in seconds). Do not change this value as the forecast algorithm needs a sample every minute.
const unsigned long SLEEP_TIME = 60000;

const char *weather[] = { "stable", "sunny", "cloudy", "unstable", "thunderstorm", "unknown" };
enum FORECAST
{
  STABLE = 0,     // "Stable Weather Pattern"
  SUNNY = 1,      // "Slowly rising Good Weather", "Clear/Sunny "
  CLOUDY = 2,     // "Slowly falling L-Pressure ", "Cloudy/Rain "
  UNSTABLE = 3,   // "Quickly rising H-Press",     "Not Stable"
  THUNDERSTORM = 4, // "Quickly falling L-Press",    "Thunderstorm"
  UNKNOWN = 5     // "Unknown (More Time needed)
};

Adafruit_BMP085 bmp = Adafruit_BMP085();      // Digital Pressure Sensor

float lastPressure = -1;
float lastTemp = -1;
int lastForecast = -1;

const int LAST_SAMPLES_COUNT = 5;
float lastPressureSamples[LAST_SAMPLES_COUNT];

// this CONVERSION_FACTOR is used to convert from Pa to kPa in forecast algorithm
// get kPa/h be dividing hPa by 10
#define CONVERSION_FACTOR (1.0/10.0)

int minuteCount = 0;
bool firstRound = true;
// average value is used in forecast algorithm.
float pressureAvg;
// average after 2 hours is used as reference value for the next iteration.
float pressureAvg2;

float dP_dt;
bool metric;
MyMessage tempMsg(TEMP_CHILD, V_TEMP);
MyMessage pressureMsg(BARO_CHILD, V_PRESSURE);
MyMessage forecastMsg(BARO_CHILD, V_FORECAST);


void setup()
{
  if (!bmp.begin())
  {
    Serial.println("Could not find a valid BMP085 sensor, check wiring!");
    while (1) {}
  }
  metric = getControllerConfig().isMetric;
}

void presentation()  {
  // Send the sketch version information to the gateway and Controller
  sendSketchInfo("Pressure Sensor", "1.1");

  // Register sensors to gw (they will be created as child devices)
  present(BARO_CHILD, S_BARO);
  present(TEMP_CHILD, S_TEMP);
}

void loop()
{
  pressure = bmp.readSealevelPressure(ALTITUDE) / 100.0;
  wait(100);
  temperature = bmp.readTemperature();
  wait(100);

  if (!metric) {
    // Convert to fahrenheit
    temperature = temperature * 9.0 / 5.0 + 32.0;
  }


  pressure_mm = pressure * 0.75006375541921;


  int forecast = sample(pressure);

  Serial.print("Temperature = ");
  Serial.print(temperature);
  Serial.println(metric ? " *C" : " *F");
  Serial.print("Pressure = ");
  Serial.print(pressure);
  Serial.print(" hPa | ");
  Serial.print(pressure_mm);
  Serial.println(" mm");
  Serial.print("Forecast = ");
  Serial.println(weather[forecast]);


  if (temperature != lastTemp)
  {
    send(tempMsg.set(temperature, 1));
    lastTemp = temperature;
  }

  if (pressure != lastPressure)
  {
    send(pressureMsg.set(pressure_mm, 0));
    lastPressure = pressure_mm;
  }

  if (forecast != lastForecast)
  {
    send(forecastMsg.set(weather[forecast]));
    lastForecast = forecast;
  }

  sleep(SLEEP_TIME);
}

float getLastPressureSamplesAverage()
{
  float lastPressureSamplesAverage = 0;
  for (int i = 0; i < LAST_SAMPLES_COUNT; i++)
  {
    lastPressureSamplesAverage += lastPressureSamples[i];
  }
  lastPressureSamplesAverage /= LAST_SAMPLES_COUNT;

  return lastPressureSamplesAverage;
}



// Algorithm found here
// http://www.freescale.com/files/sensors/doc/app_note/AN3914.pdf
// Pressure in hPa -->  forecast done by calculating kPa/h
int sample(float pressure)
{
  // Calculate the average of the last n minutes.
  int index = minuteCount % LAST_SAMPLES_COUNT;
  lastPressureSamples[index] = pressure;

  minuteCount++;
  if (minuteCount > 185)
  {
    minuteCount = 6;
  }

  if (minuteCount == 5)
  {
    pressureAvg = getLastPressureSamplesAverage();
  }
  else if (minuteCount == 35)
  {
    float lastPressureAvg = getLastPressureSamplesAverage();
    float change = (lastPressureAvg - pressureAvg) * CONVERSION_FACTOR;
    if (firstRound) // first time initial 3 hour
    {
      dP_dt = change * 2; // note this is for t = 0.5hour
    }
    else
    {
      dP_dt = change / 1.5; // divide by 1.5 as this is the difference in time from 0 value.
    }
  }
  else if (minuteCount == 65)
  {
    float lastPressureAvg = getLastPressureSamplesAverage();
    float change = (lastPressureAvg - pressureAvg) * CONVERSION_FACTOR;
    if (firstRound) //first time initial 3 hour
    {
      dP_dt = change; //note this is for t = 1 hour
    }
    else
    {
      dP_dt = change / 2; //divide by 2 as this is the difference in time from 0 value
    }
  }
  else if (minuteCount == 95)
  {
    float lastPressureAvg = getLastPressureSamplesAverage();
    float change = (lastPressureAvg - pressureAvg) * CONVERSION_FACTOR;
    if (firstRound) // first time initial 3 hour
    {
      dP_dt = change / 1.5; // note this is for t = 1.5 hour
    }
    else
    {
      dP_dt = change / 2.5; // divide by 2.5 as this is the difference in time from 0 value
    }
  }
  else if (minuteCount == 125)
  {
    float lastPressureAvg = getLastPressureSamplesAverage();
    pressureAvg2 = lastPressureAvg; // store for later use.
    float change = (lastPressureAvg - pressureAvg) * CONVERSION_FACTOR;
    if (firstRound) // first time initial 3 hour
    {
      dP_dt = change / 2; // note this is for t = 2 hour
    }
    else
    {
      dP_dt = change / 3; // divide by 3 as this is the difference in time from 0 value
    }
  }
  else if (minuteCount == 155)
  {
    float lastPressureAvg = getLastPressureSamplesAverage();
    float change = (lastPressureAvg - pressureAvg) * CONVERSION_FACTOR;
    if (firstRound) // first time initial 3 hour
    {
      dP_dt = change / 2.5; // note this is for t = 2.5 hour
    }
    else
    {
      dP_dt = change / 3.5; // divide by 3.5 as this is the difference in time from 0 value
    }
  }
  else if (minuteCount == 185)
  {
    float lastPressureAvg = getLastPressureSamplesAverage();
    float change = (lastPressureAvg - pressureAvg) * CONVERSION_FACTOR;
    if (firstRound) // first time initial 3 hour
    {
      dP_dt = change / 3; // note this is for t = 3 hour
    }
    else
    {
      dP_dt = change / 4; // divide by 4 as this is the difference in time from 0 value
    }
    pressureAvg = pressureAvg2; // Equating the pressure at 0 to the pressure at 2 hour after 3 hours have past.
    firstRound = false; // flag to let you know that this is on the past 3 hour mark. Initialized to 0 outside main loop.
  }

  int forecast = UNKNOWN;
  if (minuteCount < 35 && firstRound) //if time is less than 35 min on the first 3 hour interval.
  {
    forecast = UNKNOWN;
  }
  else if (dP_dt < (-0.25))
  {
    forecast = THUNDERSTORM;
  }
  else if (dP_dt > 0.25)
  {
    forecast = UNSTABLE;
  }
  else if ((dP_dt > (-0.25)) && (dP_dt < (-0.05)))
  {
    forecast = CLOUDY;
  }
  else if ((dP_dt > 0.05) && (dP_dt < 0.25))
  {
    forecast = SUNNY;
  }
  else if ((dP_dt > (-0.05)) && (dP_dt < 0.05))
  {
    forecast = STABLE;
  }
  else
  {
    forecast = UNKNOWN;
  }

  // uncomment when debugging
  //Serial.print(F("Forecast at minute "));
  //Serial.print(minuteCount);
  //Serial.print(F(" dP/dt = "));
  //Serial.print(dP_dt);
  //Serial.print(F("kPa/h --> "));
  //Serial.println(weather[forecast]);

  return forecast;
}

Re: Сенсор давления на BMP-180

Добавлено: 12 май 2019, 14:40
MEHANICUS
В догонку модифицированная Библиотека

Re: Сенсор давления на BMP-180

Добавлено: 12 май 2019, 14:44
MEHANICUS
Использовал такой вот вид датчика- Elecrow GY 68 BMP180