191 lines
6.7 KiB
Arduino
191 lines
6.7 KiB
Arduino
#include <SPI.h>
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#include <MySensor.h>
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#include <Wire.h>
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#include <Adafruit_BMP085.h>
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#define BARO_CHILD 0
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#define TEMP_CHILD 1
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unsigned long SLEEP_TIME = 60000; // Sleep time between reads (in seconds)
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Adafruit_BMP085 bmp = Adafruit_BMP085(); // Digital Pressure Sensor
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MySensor gw;
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float lastPressure = -1;
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float lastTemp = -1;
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int lastForecast = -1;
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char *weather[] = {"stable","sunny","cloudy","unstable","thunderstorm","unknown"};
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int minutes;
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float pressureSamples[180];
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int minuteCount = 0;
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bool firstRound = true;
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float pressureAvg[7];
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float dP_dt;
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boolean metric;
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MyMessage tempMsg(TEMP_CHILD, V_TEMP);
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MyMessage pressureMsg(BARO_CHILD, V_PRESSURE);
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MyMessage forecastMsg(BARO_CHILD, V_FORECAST);
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void setup() {
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gw.begin();
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// Send the sketch version information to the gateway and Controller
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gw.sendSketchInfo("Pressure Sensor", "1.0");
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if (!bmp.begin()) {
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Serial.println("Could not find a valid BMP085 sensor, check wiring!");
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while (1) { }
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}
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// Register sensors to gw (they will be created as child devices)
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gw.present(BARO_CHILD, S_BARO);
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gw.present(TEMP_CHILD, S_TEMP);
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metric = gw.getConfig().isMetric;
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}
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void loop() {
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float pressure = bmp.readPressure()/100;
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float temperature = bmp.readTemperature();
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if (!metric) {
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// Convert to fahrenheit
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temperature = temperature * 9.0 / 5.0 + 32.0;
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}
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int forecast = sample(pressure);
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Serial.print("Temperature = ");
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Serial.print(temperature);
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Serial.println(metric?" *C":" *F");
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Serial.print("Pressure = ");
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Serial.print(pressure);
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Serial.println(" Pa");
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Serial.println(weather[forecast]);
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if (temperature != lastTemp) {
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gw.send(tempMsg.set(temperature,1));
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lastTemp = temperature;
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}
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if (pressure != lastPressure) {
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gw.send(pressureMsg.set(pressure, 0));
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lastPressure = pressure;
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}
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if (forecast != lastForecast) {
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gw.send(forecastMsg.set(weather[forecast]));
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lastForecast = forecast;
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}
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/*
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DP/Dt explanation
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0 = "Stable Weather Pattern"
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1 = "Slowly rising Good Weather", "Clear/Sunny "
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2 = "Slowly falling L-Pressure ", "Cloudy/Rain "
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3 = "Quickly rising H-Press", "Not Stable"
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4 = "Quickly falling L-Press", "Thunderstorm"
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5 = "Unknown (More Time needed)
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*/
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gw.sleep(SLEEP_TIME);
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}
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int sample(float pressure) {
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// Algorithm found here
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// http://www.freescale.com/files/sensors/doc/app_note/AN3914.pdf
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if (minuteCount > 180)
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minuteCount = 6;
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pressureSamples[minuteCount] = pressure;
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minuteCount++;
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if (minuteCount == 5) {
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// Avg pressure in first 5 min, value averaged from 0 to 5 min.
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pressureAvg[0] = ((pressureSamples[1] + pressureSamples[2]
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+ pressureSamples[3] + pressureSamples[4] + pressureSamples[5])
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/ 5);
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} else if (minuteCount == 35) {
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// Avg pressure in 30 min, value averaged from 0 to 5 min.
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pressureAvg[1] = ((pressureSamples[30] + pressureSamples[31]
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+ pressureSamples[32] + pressureSamples[33]
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+ pressureSamples[34]) / 5);
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float change = (pressureAvg[1] - pressureAvg[0]);
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if (firstRound) // first time initial 3 hour
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dP_dt = ((65.0 / 1023.0) * 2 * change); // note this is for t = 0.5hour
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else
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dP_dt = (((65.0 / 1023.0) * change) / 1.5); // divide by 1.5 as this is the difference in time from 0 value.
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} else if (minuteCount == 60) {
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// Avg pressure at end of the hour, value averaged from 0 to 5 min.
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pressureAvg[2] = ((pressureSamples[55] + pressureSamples[56]
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+ pressureSamples[57] + pressureSamples[58]
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+ pressureSamples[59]) / 5);
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float change = (pressureAvg[2] - pressureAvg[0]);
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if (firstRound) //first time initial 3 hour
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dP_dt = ((65.0 / 1023.0) * change); //note this is for t = 1 hour
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else
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dP_dt = (((65.0 / 1023.0) * change) / 2); //divide by 2 as this is the difference in time from 0 value
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} else if (minuteCount == 95) {
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// Avg pressure at end of the hour, value averaged from 0 to 5 min.
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pressureAvg[3] = ((pressureSamples[90] + pressureSamples[91]
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+ pressureSamples[92] + pressureSamples[93]
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+ pressureSamples[94]) / 5);
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float change = (pressureAvg[3] - pressureAvg[0]);
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if (firstRound) // first time initial 3 hour
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dP_dt = (((65.0 / 1023.0) * change) / 1.5); // note this is for t = 1.5 hour
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else
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dP_dt = (((65.0 / 1023.0) * change) / 2.5); // divide by 2.5 as this is the difference in time from 0 value
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} else if (minuteCount == 120) {
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// Avg pressure at end of the hour, value averaged from 0 to 5 min.
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pressureAvg[4] = ((pressureSamples[115] + pressureSamples[116]
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+ pressureSamples[117] + pressureSamples[118]
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+ pressureSamples[119]) / 5);
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float change = (pressureAvg[4] - pressureAvg[0]);
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if (firstRound) // first time initial 3 hour
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dP_dt = (((65.0 / 1023.0) * change) / 2); // note this is for t = 2 hour
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else
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dP_dt = (((65.0 / 1023.0) * change) / 3); // divide by 3 as this is the difference in time from 0 value
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} else if (minuteCount == 155) {
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// Avg pressure at end of the hour, value averaged from 0 to 5 min.
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pressureAvg[5] = ((pressureSamples[150] + pressureSamples[151]
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+ pressureSamples[152] + pressureSamples[153]
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+ pressureSamples[154]) / 5);
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float change = (pressureAvg[5] - pressureAvg[0]);
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if (firstRound) // first time initial 3 hour
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dP_dt = (((65.0 / 1023.0) * change) / 2.5); // note this is for t = 2.5 hour
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else
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dP_dt = (((65.0 / 1023.0) * change) / 3.5); // divide by 3.5 as this is the difference in time from 0 value
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} else if (minuteCount == 180) {
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// Avg pressure at end of the hour, value averaged from 0 to 5 min.
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pressureAvg[6] = ((pressureSamples[175] + pressureSamples[176]
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+ pressureSamples[177] + pressureSamples[178]
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+ pressureSamples[179]) / 5);
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float change = (pressureAvg[6] - pressureAvg[0]);
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if (firstRound) // first time initial 3 hour
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dP_dt = (((65.0 / 1023.0) * change) / 3); // note this is for t = 3 hour
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else
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dP_dt = (((65.0 / 1023.0) * change) / 4); // divide by 4 as this is the difference in time from 0 value
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pressureAvg[0] = pressureAvg[5]; // Equating the pressure at 0 to the pressure at 2 hour after 3 hours have past.
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firstRound = false; // flag to let you know that this is on the past 3 hour mark. Initialized to 0 outside main loop.
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}
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if (minuteCount < 35 && firstRound) //if time is less than 35 min on the first 3 hour interval.
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return 5; // Unknown, more time needed
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else if (dP_dt < (-0.25))
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return 4; // Quickly falling LP, Thunderstorm, not stable
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else if (dP_dt > 0.25)
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return 3; // Quickly rising HP, not stable weather
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else if ((dP_dt > (-0.25)) && (dP_dt < (-0.05)))
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return 2; // Slowly falling Low Pressure System, stable rainy weather
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else if ((dP_dt > 0.05) && (dP_dt < 0.25))
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return 1; // Slowly rising HP stable good weather
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else if ((dP_dt > (-0.05)) && (dP_dt < 0.05))
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return 0; // Stable weather
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else
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return 5; // Unknown
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}
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