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Refactored forecast algorithm

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- reduced footprint by storing only the last few samples instead of all 180
- fixed wrong calculation: 65/1023 factor replaced with a conversion factor hPa to kPa
- fixed error when 180 minutes were reached: sketch started at 5 min instead of 6 triggering a wrong average calculation

Cleaned up code
- removed unused variable
- fixed unit Pa to hPa in serial print
- introduced constants and enum for better readability

Signed-off-by: windkh <karl-heinz.wind@web.de>

I agree to the CLA!
This commit is contained in:
windkh
2015-07-08 22:37:38 +02:00
parent 734313e735
commit 5d7fe779e0
1 changed files with 194 additions and 157 deletions
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libraries/MySensors/examples/PressureSensor/PressureSensor.ino
+189 -152
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@@ -6,7 +6,21 @@
#define BARO_CHILD 0 #define BARO_CHILD 0
#define TEMP_CHILD 1 #define TEMP_CHILD 1
unsigned long SLEEP_TIME = 60000; // Sleep time between reads (in seconds) const float ALTITUDE = 688; // <-- adapt this value to your own location's altitude.
// 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 Adafruit_BMP085 bmp = Adafruit_BMP085(); // Digital Pressure Sensor
MySensor gw; MySensor gw;
@@ -14,206 +28,229 @@ MySensor gw;
float lastPressure = -1; float lastPressure = -1;
float lastTemp = -1; float lastTemp = -1;
int lastForecast = -1; int lastForecast = -1;
const char *weather[] = {"stable","sunny","cloudy","unstable","thunderstorm","unknown"};
int minutes; const int LAST_SAMPLES_COUNT = 5;
float pressureSamples[7][6]; 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; int minuteCount = 0;
bool firstRound = true; bool firstRound = true;
float pressureAvg[7]; float pressureAvg[7];
float dP_dt; float dP_dt;
boolean metric; boolean metric;
MyMessage tempMsg(TEMP_CHILD, V_TEMP); MyMessage tempMsg(TEMP_CHILD, V_TEMP);
MyMessage pressureMsg(BARO_CHILD, V_PRESSURE); MyMessage pressureMsg(BARO_CHILD, V_PRESSURE);
MyMessage forecastMsg(BARO_CHILD, V_FORECAST); MyMessage forecastMsg(BARO_CHILD, V_FORECAST);
void setup() {
gw.begin();
// Send the sketch version information to the gateway and Controller void setup()
gw.sendSketchInfo("Pressure Sensor", "1.0"); {
gw.begin();
if (!bmp.begin()) { // Send the sketch version information to the gateway and Controller
Serial.println("Could not find a valid BMP085 sensor, check wiring!"); gw.sendSketchInfo("Pressure Sensor", "1.1");
while (1) { }
}
// Register sensors to gw (they will be created as child devices) if (!bmp.begin())
gw.present(BARO_CHILD, S_BARO); {
gw.present(TEMP_CHILD, S_TEMP); Serial.println("Could not find a valid BMP085 sensor, check wiring!");
metric = gw.getConfig().isMetric; while (1) {}
}
// Register sensors to gw (they will be created as child devices)
gw.present(BARO_CHILD, S_BARO);
gw.present(TEMP_CHILD, S_TEMP);
metric = gw.getConfig().isMetric;
} }
void loop() { void loop()
float pressure = bmp.readSealevelPressure(205)/100.0; // 205 meters above sealevel {
float temperature = bmp.readTemperature(); float pressure = bmp.readSealevelPressure(ALTITUDE) / 100.0;
float temperature = bmp.readTemperature();
if (!metric) { if (!metric)
// Convert to fahrenheit {
temperature = temperature * 9.0 / 5.0 + 32.0; // Convert to fahrenheit
} temperature = temperature * 9.0 / 5.0 + 32.0;
}
int forecast = sample(pressure); int forecast = sample(pressure);
Serial.print("Temperature = "); Serial.print("Temperature = ");
Serial.print(temperature); Serial.print(temperature);
Serial.println(metric?" *C":" *F"); Serial.println(metric ? " *C" : " *F");
Serial.print("Pressure = "); Serial.print("Pressure = ");
Serial.print(pressure); Serial.print(pressure);
Serial.println(" Pa"); Serial.println(" hPa");
Serial.println(weather[forecast]); Serial.print("Forecast = ");
Serial.println(weather[forecast]);
if (temperature != lastTemp) { if (temperature != lastTemp)
gw.send(tempMsg.set(temperature,1)); {
lastTemp = temperature; gw.send(tempMsg.set(temperature, 1));
} lastTemp = temperature;
}
if (pressure != lastPressure) { if (pressure != lastPressure)
gw.send(pressureMsg.set(pressure, 0)); {
lastPressure = pressure; gw.send(pressureMsg.set(pressure, 0));
} lastPressure = pressure;
}
if (forecast != lastForecast) { if (forecast != lastForecast)
gw.send(forecastMsg.set(weather[forecast])); {
lastForecast = forecast; gw.send(forecastMsg.set(weather[forecast]));
} lastForecast = forecast;
}
/* gw.sleep(SLEEP_TIME);
DP/Dt explanation
0 = "Stable Weather Pattern"
1 = "Slowly rising Good Weather", "Clear/Sunny "
2 = "Slowly falling L-Pressure ", "Cloudy/Rain "
3 = "Quickly rising H-Press", "Not Stable"
4 = "Quickly falling L-Press", "Thunderstorm"
5 = "Unknown (More Time needed)
*/
gw.sleep(SLEEP_TIME);
} }
int sample(float pressure) { float getLastPressureSamplesAverage()
// Algorithm found here {
// http://www.freescale.com/files/sensors/doc/app_note/AN3914.pdf float lastPressureSamplesAverage = 0;
if (minuteCount == 180) for (int i = 0; i < LAST_SAMPLES_COUNT; i++)
minuteCount = 5; {
lastPressureSamplesAverage += lastPressureSamples[i];
}
lastPressureSamplesAverage /= LAST_SAMPLES_COUNT;
//From 0 to 5 min. return lastPressureSamplesAverage;
if (minuteCount <= 5){ }
pressureSamples[0][minuteCount] = pressure;
}
//From 30 to 35 min.
if ((minuteCount <= 30) && (minuteCount >= 35)){
pressureSamples[1][minuteCount - 30] = pressure;
}
//From 55 to 60 min.
if ((minuteCount <= 55) && (minuteCount >= 60)){
pressureSamples[2][minuteCount - 55] = pressure;
}
//From 90 to 95 min.
if ((minuteCount <= 90) && (minuteCount >= 95)){
pressureSamples[3][minuteCount - 90] = pressure;
}
//From 115 to 119 min.
if ((minuteCount <= 115) && (minuteCount >= 120)){
pressureSamples[4][minuteCount - 115] = pressure;
}
//From 150 to 155 min.
if ((minuteCount <= 150) && (minuteCount >= 155)){
pressureSamples[5][minuteCount - 150] = pressure;
}
//From 175 to 180 min.
if ((minuteCount <= 175) && (minuteCount >= 180)){
pressureSamples[6][minuteCount - 175] = pressure;
}
// 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++; minuteCount++;
if (minuteCount > 185)
{
minuteCount = 6;
}
if (minuteCount == 5) { if (minuteCount == 5)
// Avg pressure in first 5 min, value averaged from 0 to 5 min. {
pressureAvg[0] = ((pressureSamples[0][0] + pressureSamples[0][1] pressureAvg[0] = getLastPressureSamplesAverage();
+ pressureSamples[0][2] + pressureSamples[0][3] }
+ pressureSamples[0][4] + pressureSamples[0][5]) / 6); else if (minuteCount == 35)
} else if (minuteCount == 35) { {
// Avg pressure in 30 min, value averaged from 0 to 5 min. pressureAvg[1] = getLastPressureSamplesAverage();
pressureAvg[1] = ((pressureSamples[1][0] + pressureSamples[1][1] float change = (pressureAvg[1] - pressureAvg[0]) * CONVERSION_FACTOR;
+ pressureSamples[1][2] + pressureSamples[1][3]
+ pressureSamples[1][4] + pressureSamples[1][5]) / 6);
float change = (pressureAvg[1] - pressureAvg[0]);
if (firstRound) // first time initial 3 hour if (firstRound) // first time initial 3 hour
dP_dt = ((65.0 / 1023.0) * 2 * change); // note this is for t = 0.5hour {
dP_dt = change * 2; // note this is for t = 0.5hour
}
else else
dP_dt = (((65.0 / 1023.0) * change) / 1.5); // divide by 1.5 as this is the difference in time from 0 value. {
} else if (minuteCount == 60) { dP_dt = change / 1.5; // divide by 1.5 as this is the difference in time from 0 value.
// 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] else if (minuteCount == 65)
+ pressureSamples[2][4] + pressureSamples[2][5]) / 6); {
float change = (pressureAvg[2] - pressureAvg[0]); pressureAvg[2] = getLastPressureSamplesAverage();
float change = (pressureAvg[2] - pressureAvg[0]) * CONVERSION_FACTOR;
if (firstRound) //first time initial 3 hour if (firstRound) //first time initial 3 hour
dP_dt = ((65.0 / 1023.0) * change); //note this is for t = 1 hour {
dP_dt = change; //note this is for t = 1 hour
}
else else
dP_dt = (((65.0 / 1023.0) * change) / 2); //divide by 2 as this is the difference in time from 0 value {
} else if (minuteCount == 95) { dP_dt = change / 2; //divide by 2 as this is the difference in time from 0 value
// 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] else if (minuteCount == 95)
+ pressureSamples[3][4] + pressureSamples[3][5]) / 6); {
float change = (pressureAvg[3] - pressureAvg[0]); pressureAvg[3] = getLastPressureSamplesAverage();
float change = (pressureAvg[3] - pressureAvg[0]) * CONVERSION_FACTOR;
if (firstRound) // first time initial 3 hour if (firstRound) // first time initial 3 hour
dP_dt = (((65.0 / 1023.0) * change) / 1.5); // note this is for t = 1.5 hour {
dP_dt = change / 1.5; // note this is for t = 1.5 hour
}
else else
dP_dt = (((65.0 / 1023.0) * change) / 2.5); // divide by 2.5 as this is the difference in time from 0 value {
} else if (minuteCount == 120) { dP_dt = change / 2.5; // divide by 2.5 as this is the difference in time from 0 value
// 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] else if (minuteCount == 125)
+ pressureSamples[4][4] + pressureSamples[4][5]) / 6); {
float change = (pressureAvg[4] - pressureAvg[0]); pressureAvg[4] = getLastPressureSamplesAverage();
float change = (pressureAvg[4] - pressureAvg[0]) * CONVERSION_FACTOR;
if (firstRound) // first time initial 3 hour if (firstRound) // first time initial 3 hour
dP_dt = (((65.0 / 1023.0) * change) / 2); // note this is for t = 2 hour {
dP_dt = change / 2; // note this is for t = 2 hour
}
else else
dP_dt = (((65.0 / 1023.0) * change) / 3); // divide by 3 as this is the difference in time from 0 value {
} else if (minuteCount == 155) { dP_dt = change / 3; // divide by 3 as this is the difference in time from 0 value
// 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] else if (minuteCount == 155)
+ pressureSamples[5][4] + pressureSamples[5][5]) / 6); {
float change = (pressureAvg[5] - pressureAvg[0]); pressureAvg[5] = getLastPressureSamplesAverage();
float change = (pressureAvg[5] - pressureAvg[0]) * CONVERSION_FACTOR;
if (firstRound) // first time initial 3 hour if (firstRound) // first time initial 3 hour
dP_dt = (((65.0 / 1023.0) * change) / 2.5); // note this is for t = 2.5 hour {
dP_dt = change / 2.5; // note this is for t = 2.5 hour
}
else else
dP_dt = (((65.0 / 1023.0) * change) / 3.5); // divide by 3.5 as this is the difference in time from 0 value {
} else if (minuteCount == 180) { dP_dt = change / 3.5; // divide by 3.5 as this is the difference in time from 0 value
// 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] else if (minuteCount == 185)
+ pressureSamples[6][4] + pressureSamples[6][5]) / 6); {
float change = (pressureAvg[6] - pressureAvg[0]); pressureAvg[6] = getLastPressureSamplesAverage();
float change = (pressureAvg[6] - pressureAvg[0]) * CONVERSION_FACTOR;
if (firstRound) // first time initial 3 hour if (firstRound) // first time initial 3 hour
dP_dt = (((65.0 / 1023.0) * change) / 3); // note this is for t = 3 hour {
dP_dt = change / 3; // note this is for t = 3 hour
}
else else
dP_dt = (((65.0 / 1023.0) * change) / 4); // divide by 4 as this is the difference in time from 0 value {
dP_dt = change / 4; // divide by 4 as this is the difference in time from 0 value
}
pressureAvg[0] = pressureAvg[5]; // Equating the pressure at 0 to the pressure at 2 hour after 3 hours have past. pressureAvg[0] = pressureAvg[5]; // 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. 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. if (minuteCount < 35 && firstRound) //if time is less than 35 min on the first 3 hour interval.
return 5; // Unknown, more time needed {
forecast = UNKNOWN;
}
else if (dP_dt < (-0.25)) else if (dP_dt < (-0.25))
return 4; // Quickly falling LP, Thunderstorm, not stable {
forecast = THUNDERSTORM;
}
else if (dP_dt > 0.25) else if (dP_dt > 0.25)
return 3; // Quickly rising HP, not stable weather {
forecast = UNSTABLE;
}
else if ((dP_dt > (-0.25)) && (dP_dt < (-0.05))) else if ((dP_dt > (-0.25)) && (dP_dt < (-0.05)))
return 2; // Slowly falling Low Pressure System, stable rainy weather {
forecast = CLOUDY;
}
else if ((dP_dt > 0.05) && (dP_dt < 0.25)) 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)) forecast = SUNNY;
return 0; // Stable weather }
else if ((dP_dt >(-0.05)) && (dP_dt < 0.05))
{
forecast = STABLE;
}
else else
return 5; // Unknown {
forecast = UNKNOWN;
}
return forecast;
} }