Added ESP8266 air pressure examle

Added ESP8266 air pressure examle

Esp8266EasyIoT/examples/esp_pressure/esp_pressure.ino

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+#include <Esp8266EasyIoT.h>
+#include <SFE_BMP180.h>
+#include <Wire.h>
+
+
+#define ALTITUDE 301.0 // Altitude of my home
+#define ESP_RESET_PIN     12
+
+#define MILS_IN_MIN  1000
+
+#define CHILD_ID_TEMP        0
+#define CHILD_ID_BARO        1
+
+
+int minuteCount = 0;
+double pressureSamples[9][6];
+double pressureAvg[9];
+double dP_dt;
+
+const char *weather[] = {
+  "stable","sunny","cloudy","unstable","thunderstorm","unknown"};
+
+int forecast = 5;
+
+unsigned long startTime;
+
+SFE_BMP180 bmp180;
+Esp8266EasyIoT esp; 
+
+
+Esp8266EasyIoTMsg msgTemp(CHILD_ID_TEMP, V_TEMP);
+Esp8266EasyIoTMsg msgPress(CHILD_ID_BARO, V_PRESSURE);
+Esp8266EasyIoTMsg msgForec(CHILD_ID_BARO, V_FORECAST);
+
+void setup()
+{  
+  Serial1.begin(9600); // ESP
+  Serial.begin(115200); // debug
+
+  if (bmp180.begin())
+    Serial.println("BMP180 init success");
+   else
+     {
+    // Oops, something went wrong, this is usually a connection problem,
+    // see the comments at the top of this sketch for the proper connections.
+
+    Serial.println("BMP180 init fail\n\n");
+    while(1); // Pause forever.
+  }
+
+   startTime =  -1;
+
+  esp.begin(NULL, ESP_RESET_PIN, &Serial1, &Serial);
+
+  esp.present(CHILD_ID_TEMP, S_TEMP);
+  esp.present(CHILD_ID_BARO, S_BARO);
+}
+
+
+void loop()
+{
+
+  for(int i =0; i<10;i++)
+  {
+    if (esp.process())
+      break;
+  }
+
+
+  if (IsTimeout())
+  {
+  char status;
+  double T,P,p0,a;
+
+  // Loop here getting pressure readings every 60 seconds.
+
+  // If you want sea-level-compensated pressure, as used in weather reports,
+  // you will need to know the altitude at which your measurements are taken.
+  // We're using a constant called ALTITUDE in this sketch:
+
+  // If you want to measure altitude, and not pressure, you will instead need
+  // to provide a known baseline pressure. This is shown at the end of the sketch.
+
+  // You must first get a temperature measurement to perform a pressure reading.
+
+  // Start a temperature measurement:
+  // If request is successful, the number of ms to wait is returned.
+  // If request is unsuccessful, 0 is returned.
+
+  status = bmp180.startTemperature();
+  if (status != 0)
+  {
+    // Wait for the measurement to complete:
+    delay(status);
+
+    // Retrieve the completed temperature measurement:
+    // Note that the measurement is stored in the variable T.
+    // Function returns 1 if successful, 0 if failure.
+
+    status = bmp180.getTemperature(T);
+    if (status != 0)
+    {
+      // Print out the measurement:
+      Serial.print("temperature: ");
+      Serial.print(T,2);
+      Serial.print(" deg C, ");
+      Serial.print((9.0/5.0)*T+32.0,2);
+      Serial.println(" deg F");
+
+
+      static int lastSendTempInt;
+      int temp = round(T *10);
+
+      if (temp != lastSendTempInt)
+      {
+        lastSendTempInt = temp;      
+        esp.send(msgTemp.set((float)T, 1));
+      }
+
+      // Start a pressure measurement:
+      // The parameter is the oversampling setting, from 0 to 3 (highest res, longest wait).
+      // If request is successful, the number of ms to wait is returned.
+      // If request is unsuccessful, 0 is returned.
+
+      status = bmp180.startPressure(3);
+      if (status != 0)
+      {
+        // Wait for the measurement to complete:
+        delay(status);
+
+        // Retrieve the completed pressure measurement:
+        // Note that the measurement is stored in the variable P.
+        // Note also that the function requires the previous temperature measurement (T).
+        // (If temperature is stable, you can do one temperature measurement for a number of pressure measurements.)
+        // Function returns 1 if successful, 0 if failure.
+
+        status = bmp180.getPressure(P,T);
+        if (status != 0)
+        {
+          // The pressure sensor returns abolute pressure, which varies with altitude.
+          // To remove the effects of altitude, use the sealevel function and your current altitude.
+          // This number is commonly used in weather reports.
+          // Parameters: P = absolute pressure in mb, ALTITUDE = current altitude in m.
+          // Result: p0 = sea-level compensated pressure in mb
+
+          p0 = bmp180.sealevel(P,ALTITUDE); // we're at 1655 meters (Boulder, CO)
+          Serial.print("relative (sea-level) pressure: ");
+          Serial.print(p0,2);
+          Serial.print(" mb, ");
+          Serial.print(p0*0.0295333727,2);
+          Serial.println(" inHg");
+
+
+          static int lastSendPresInt;
+          int pres = round(p0 *10);
+
+          if (pres != lastSendPresInt)
+          {
+            lastSendPresInt = pres;      
+            esp.send(msgPress.set((float)p0, 1));
+          }
+
+          forecast = calculateForecast(p0);
+          static int lastSendForeInt = -1;
+
+
+          if (forecast != lastSendForeInt)
+          {
+            lastSendForeInt = forecast;      
+            esp.send(msgForec.set(weather[forecast]));
+          }
+        }
+        else Serial.println("error retrieving pressure measurement\n");
+      }
+      else Serial.println("error starting pressure measurement\n");
+    }
+    else Serial.println("error retrieving temperature measurement\n");
+  }
+  else Serial.println("error starting temperature measurement\n");
+
+  startTime = millis();  
+}
+
+  //delay(5000);  // Pause for 5 seconds.
+}
+
+boolean IsTimeout()
+{
+  unsigned long now = millis();
+  if (startTime <= now)
+  {
+    if ( (unsigned long)(now - startTime )  < MILS_IN_MIN ) 
+      return false;
+  }
+  else
+  {
+    if ( (unsigned long)(startTime - now) < MILS_IN_MIN ) 
+      return false;
+  }
+
+  return true;
+}
+
+
+int calculateForecast(double pressure) {
+  //From 0 to 5 min.
+  if (minuteCount <= 5){
+    pressureSamples[0][minuteCount] = pressure;
+  }
+  //From 30 to 35 min.
+  else if ((minuteCount >= 30) && (minuteCount <= 35)){
+    pressureSamples[1][minuteCount - 30] = pressure;  
+  }
+  //From 60 to 65 min.
+  else if ((minuteCount >= 60) && (minuteCount <= 65)){
+    pressureSamples[2][minuteCount - 60] = pressure;  
+  }  
+  //From 90 to 95 min.
+  else if ((minuteCount >= 90) && (minuteCount <= 95)){
+    pressureSamples[3][minuteCount - 90] = pressure;  
+  }
+  //From 120 to 125 min.
+  else if ((minuteCount >= 120) && (minuteCount <= 125)){
+    pressureSamples[4][minuteCount - 120] = pressure;  
+  }
+  //From 150 to 155 min.
+  else if ((minuteCount >= 150) && (minuteCount <= 155)){
+    pressureSamples[5][minuteCount - 150] = pressure;  
+  }
+  //From 180 to 185 min.
+  else if ((minuteCount >= 180) && (minuteCount <= 185)){
+    pressureSamples[6][minuteCount - 180] = pressure;  
+  }
+  //From 210 to 215 min.
+  else if ((minuteCount >= 210) && (minuteCount <= 215)){
+    pressureSamples[7][minuteCount - 210] = pressure;  
+  }
+  //From 240 to 245 min.
+  else if ((minuteCount >= 240) && (minuteCount <= 245)){
+    pressureSamples[8][minuteCount - 240] = pressure;  
+  }
+
+
+  if (minuteCount == 5) {
+    // Avg pressure in first 5 min, value averaged from 0 to 5 min.
+    pressureAvg[0] = ((pressureSamples[0][0] + pressureSamples[0][1] 
+      + pressureSamples[0][2] + pressureSamples[0][3]
+      + pressureSamples[0][4] + pressureSamples[0][5]) / 6);
+  } 
+  else if (minuteCount == 35) {
+    // Avg pressure in 30 min, value averaged from 0 to 5 min.
+    pressureAvg[1] = ((pressureSamples[1][0] + pressureSamples[1][1] 
+      + pressureSamples[1][2] + pressureSamples[1][3]
+      + pressureSamples[1][4] + pressureSamples[1][5]) / 6);
+    float change = (pressureAvg[1] - pressureAvg[0]);
+      dP_dt = change / 5; 
+  } 
+  else if (minuteCount == 65) {
+    // Avg pressure at end of the hour, value averaged from 0 to 5 min.
+    pressureAvg[2] = ((pressureSamples[2][0] + pressureSamples[2][1] 
+      + pressureSamples[2][2] + pressureSamples[2][3]
+      + pressureSamples[2][4] + pressureSamples[2][5]) / 6);
+    float change = (pressureAvg[2] - pressureAvg[0]);
+      dP_dt = change / 10; 
+  } 
+  else if (minuteCount == 95) {
+    // Avg pressure at end of the hour, value averaged from 0 to 5 min.
+    pressureAvg[3] = ((pressureSamples[3][0] + pressureSamples[3][1] 
+      + pressureSamples[3][2] + pressureSamples[3][3]
+      + pressureSamples[3][4] + pressureSamples[3][5]) / 6);
+    float change = (pressureAvg[3] - pressureAvg[0]);
+    dP_dt = change / 15; 
+  } 
+  else if (minuteCount == 125) {
+    // Avg pressure at end of the hour, value averaged from 0 to 5 min.
+    pressureAvg[4] = ((pressureSamples[4][0] + pressureSamples[4][1] 
+      + pressureSamples[4][2] + pressureSamples[4][3]
+      + pressureSamples[4][4] + pressureSamples[4][5]) / 6);
+    float change = (pressureAvg[4] - pressureAvg[0]);
+    dP_dt = change / 20; 
+  } 
+  else if (minuteCount == 155) {
+    // Avg pressure at end of the hour, value averaged from 0 to 5 min.
+    pressureAvg[5] = ((pressureSamples[5][0] + pressureSamples[5][1] 
+      + pressureSamples[5][2] + pressureSamples[5][3]
+      + pressureSamples[5][4] + pressureSamples[5][5]) / 6);
+    float change = (pressureAvg[5] - pressureAvg[0]);
+    dP_dt = change / 25; 
+  } 
+  else if (minuteCount == 185) {
+    // Avg pressure at end of the hour, value averaged from 0 to 5 min.
+    pressureAvg[6] = ((pressureSamples[6][0] + pressureSamples[6][1] 
+      + pressureSamples[6][2] + pressureSamples[6][3]
+      + pressureSamples[6][4] + pressureSamples[6][5]) / 6);
+    float change = (pressureAvg[6] - pressureAvg[0]);
+      dP_dt = change / 30; 
+  }
+  else if (minuteCount == 215) {
+    // Avg pressure at end of the hour, value averaged from 0 to 5 min.
+    pressureAvg[7] = ((pressureSamples[7][0] + pressureSamples[7][1] 
+      + pressureSamples[7][2] + pressureSamples[7][3]
+      + pressureSamples[7][4] + pressureSamples[7][5]) / 6);
+    float change = (pressureAvg[7] - pressureAvg[0]);
+      dP_dt = change / 35; 
+  } 
+  else if (minuteCount == 245) {
+    // Avg pressure at end of the hour, value averaged from 0 to 5 min.
+    pressureAvg[8] = ((pressureSamples[8][0] + pressureSamples[8][1] 
+      + pressureSamples[8][2] + pressureSamples[8][3]
+      + pressureSamples[8][4] + pressureSamples[8][5]) / 6);
+    float change = (pressureAvg[8] - pressureAvg[0]);
+      dP_dt = change / 40; // note this is for t = 4 hour
+
+    minuteCount -= 30;
+    pressureAvg[0] = pressureAvg[1];
+    pressureAvg[1] = pressureAvg[2];
+    pressureAvg[2] = pressureAvg[3];
+    pressureAvg[3] = pressureAvg[4];
+    pressureAvg[4] = pressureAvg[5];
+    pressureAvg[5] = pressureAvg[6];
+    pressureAvg[6] = pressureAvg[7];
+    pressureAvg[7] = pressureAvg[8];
+  } 
+
+  minuteCount++;
+
+  if (minuteCount < 36) //if time is less than 35 min 
+    return 5; // Unknown, more time needed
+  else if (dP_dt < (-0.25))
+    return 4; // Quickly falling LP, Thunderstorm, not stable
+  else if (dP_dt > 0.25)
+    return 3; // Quickly rising HP, not stable weather
+  else if ((dP_dt > (-0.25)) && (dP_dt < (-0.05)))
+    return 2; // Slowly falling Low Pressure System, stable rainy weather
+  else if ((dP_dt > 0.05) && (dP_dt < 0.25))
+    return 1; // Slowly rising HP stable good weather
+  else if ((dP_dt > (-0.05)) && (dP_dt < 0.05))
+    return 0; // Stable weather
+  else
+    return 5; // Unknown
+}
+