Barometric Pressure Sensor Using MS5637



  • Hello

    Very new to Arduino and MySensors so please excuse any novice mistakes. I am trying to get the Pressure Sensor sketch to work with a different pressure sensor http://www.freetronics.com.au/collections/modules/products/barometric-pressure-sensor-module#.VLSnlNH9mUk

    I have modified the code (included below) but when I try to add it to Vera (VeraLite, UI7, Ethernet Gateway, and yes it does work with other sensors surprisingly!) no new device is included and when I open a serial monitor no response is available. I have confirmed the pressure sensor itself is working using a different sketch. Any suggestions would be appreciated.

    #include <SPI.h>
    #include <MySensor.h>
    #include <Wire.h>
    #include <BaroSensor.h>

    #define BARO_CHILD 0
    #define TEMP_CHILD 1

    unsigned long SLEEP_TIME = 60000; // Sleep time between reads (in seconds)

    BaroSensorClass bmp = BaroSensorClass(); // Digital Pressure Sensor
    MySensor gw;

    float lastPressure = -1;
    float lastTemp = -1;
    int lastForecast = -1;
    char *weather[] = {"stable","sunny","cloudy","unstable","thunderstorm","unknown"};
    int minutes;
    float pressureSamples[180];
    int minuteCount = 0;
    bool firstRound = true;
    float pressureAvg[7];
    float dP_dt;
    boolean metric;
    MyMessage tempMsg(TEMP_CHILD, V_TEMP);
    MyMessage pressureMsg(BARO_CHILD, V_PRESSURE);
    MyMessage forecastMsg(BARO_CHILD, V_FORECAST);

    void setup() {
    gw.begin();

    // Send the sketch version information to the gateway and Controller
    gw.sendSketchInfo("Pressure Sensor", "1.0");

    bmp.begin();
    // Serial.println("Could not find a valid sensor, check wiring!");
    //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() {
    float pressure = bmp.getPressure(); //(205)/100; // 205 meters above sealevel
    float temperature = bmp.getTemperature();

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

    int forecast = sample(pressure);

    Serial.print("Temperature = ");
    Serial.print(temperature);
    Serial.println(metric?" *C":" *F");
    Serial.print("Pressure = ");
    Serial.print(pressure);
    Serial.println(" Pa");
    Serial.println(weather[forecast]);

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

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

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

    /*
    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) {
    // Algorithm found here
    // http://www.freescale.com/files/sensors/doc/app_note/AN3914.pdf
    if (minuteCount == 180)
    minuteCount = 5;

    pressureSamples[minuteCount] = pressure;
    minuteCount++;
    
    if (minuteCount == 5) {
    	// Avg pressure in first 5 min, value averaged from 0 to 5 min.
    	pressureAvg[0] = ((pressureSamples[0] + pressureSamples[1]
    			+ pressureSamples[2] + pressureSamples[3] + pressureSamples[4])
    			/ 5);
    } else if (minuteCount == 35) {
    	// Avg pressure in 30 min, value averaged from 0 to 5 min.
    	pressureAvg[1] = ((pressureSamples[30] + pressureSamples[31]
    			+ pressureSamples[32] + pressureSamples[33]
    			+ pressureSamples[34]) / 5);
    	float change = (pressureAvg[1] - pressureAvg[0]);
    	if (firstRound) // first time initial 3 hour
    		dP_dt = ((65.0 / 1023.0) * 2 * change); // note this is for t = 0.5hour
    	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) {
    	// Avg pressure at end of the hour, value averaged from 0 to 5 min.
    	pressureAvg[2] = ((pressureSamples[55] + pressureSamples[56]
    			+ pressureSamples[57] + pressureSamples[58]
    			+ pressureSamples[59]) / 5);
    	float change = (pressureAvg[2] - pressureAvg[0]);
    	if (firstRound) //first time initial 3 hour
    		dP_dt = ((65.0 / 1023.0) * change); //note this is for t = 1 hour
    	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) {
    	// Avg pressure at end of the hour, value averaged from 0 to 5 min.
    	pressureAvg[3] = ((pressureSamples[90] + pressureSamples[91]
    			+ pressureSamples[92] + pressureSamples[93]
    			+ pressureSamples[94]) / 5);
    	float change = (pressureAvg[3] - pressureAvg[0]);
    	if (firstRound) // first time initial 3 hour
    		dP_dt = (((65.0 / 1023.0) * change) / 1.5); // note this is for t = 1.5 hour
    	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) {
    	// Avg pressure at end of the hour, value averaged from 0 to 5 min.
    	pressureAvg[4] = ((pressureSamples[115] + pressureSamples[116]
    			+ pressureSamples[117] + pressureSamples[118]
    			+ pressureSamples[119]) / 5);
    	float change = (pressureAvg[4] - pressureAvg[0]);
    	if (firstRound) // first time initial 3 hour
    		dP_dt = (((65.0 / 1023.0) * change) / 2); // note this is for t = 2 hour
    	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) {
    	// Avg pressure at end of the hour, value averaged from 0 to 5 min.
    	pressureAvg[5] = ((pressureSamples[150] + pressureSamples[151]
    			+ pressureSamples[152] + pressureSamples[153]
    			+ pressureSamples[154]) / 5);
    	float change = (pressureAvg[5] - pressureAvg[0]);
    	if (firstRound) // first time initial 3 hour
    		dP_dt = (((65.0 / 1023.0) * change) / 2.5); // note this is for t = 2.5 hour
    	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) {
    	// Avg pressure at end of the hour, value averaged from 0 to 5 min.
    	pressureAvg[6] = ((pressureSamples[175] + pressureSamples[176]
    			+ pressureSamples[177] + pressureSamples[178]
    			+ pressureSamples[179]) / 5);
    	float change = (pressureAvg[6] - pressureAvg[0]);
    	if (firstRound) // first time initial 3 hour
    		dP_dt = (((65.0 / 1023.0) * change) / 3); // note this is for t = 3 hour
    	else
    		dP_dt = (((65.0 / 1023.0) * 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.
    	firstRound = false; // flag to let you know that this is on the past 3 hour mark. Initialized to 0 outside main loop.
    }
    
    if (minuteCount < 35 && firstRound) //if time is less than 35 min on the first 3 hour interval.
    	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
    

    }


  • Admin

    Sorry, we aren't machines that easily do diffs in our heads... :)

    What exactly did you change and why?



  • Sorry about that, I changed

    #include <Adafruit_BMP085.h> changed to #include <BaroSensor.h> (Alternate library files for different baro sensor)
    Adafruit_BMP085 bmp = Adafruit_BMP085(); changed to BaroSensorClass bmp = BaroSensorClass(); (BaroSensorClass is referenced in the library files)
    float pressure = bmp.readSealevelPressure(205)/100; **changed to ** float pressure = bmp.getPressure(); (also referenced in the library)
    float temperature = bmp.readTemperature(); changed to float temperature = bmp.getTemperature(); (same reason)
    if (!bmp.begin()) {
    Serial.println("Could not find a valid BMP085 sensor, check wiring!");
    while (1) { } **changed to ** bmp.begin(); (Could not get the sketch to compile using the original so changed to just start the baro sensor)

    Thanks again.


  • Admin

    If you get no output in the Serial Monitor there could be a out of (stack) memory situation.

    Try adding debug prints to see where it fails.



  • Thanks, I added debug prints after each line but still get nothing on the serial monitor. Does that mean I can assume that the problem is in the initial setup section (the code before void setup(){)?

    I couldn't find a way to add debug prints to that section but any suggestions on how to are welcome.


  • Hero Member

    Did you try something like this:

    void setup()
    {
    Serial.begin(115200);
    delay(1000);
    Serial.println("Serial begin ");
    
    gw.begin
    

    Edit: newermind, I don't think you can get anything from the section before setup()


  • Contest Winner

    maybe i missed it, but did you have a sketch that worked (with the appropriate libraries) at least outputting the sensor data to the serial monitor?

    If you have that, post it. It will be easy to add to that the 'stuff' you need for MySensors, I believe.



  • Yes, I have that. It is just a really a really basic sketch that prints the sensor data to a serial output. I am also very interested in the weather forecast part of the MySensors sketch which is why I was trying to mod it.

    #include <Wire.h>
    #include <BaroSensor.h>

    void setup()
    {
    Serial.begin(9600);
    BaroSensor.begin();
    }

    void loop()
    {
    if(!BaroSensor.isOK()) {
    Serial.print("Sensor not Found/OK. Error: ");
    Serial.println(BaroSensor.getError());
    BaroSensor.begin(); // Try to reinitialise the sensor if we can
    }
    else {
    Serial.print("Temperature: ");
    Serial.println(BaroSensor.getTemperature());
    Serial.print("Pressure: ");
    Serial.println(BaroSensor.getPressure());
    }
    delay(1000);
    }


  • Contest Winner

    @Myles-L

    this compiles, but I could not test it:

    #include <SPI.h>
    #include <MySensor.h>  
    #include <Wire.h>
    #include <BaroSensor.h>
    
    #define BARO_CHILD 0
    #define TEMP_CHILD 1
    
    unsigned long SLEEP_TIME = 60000; // Sleep time between reads (in seconds)
    
    MySensor gw;
    
    float lastPressure = -1;
    float lastTemp = -1;
    int lastForecast = -1;
    const char *weather[] = {"stable","sunny","cloudy","unstable","thunderstorm","unknown"};
    int minutes;
    float pressureSamples[180];
    int minuteCount = 0;
    bool firstRound = true;
    float pressureAvg[7];
    float dP_dt;
    boolean metric; 
    MyMessage tempMsg(TEMP_CHILD, V_TEMP);
    MyMessage pressureMsg(BARO_CHILD, V_PRESSURE);
    MyMessage forecastMsg(BARO_CHILD, V_FORECAST);
    
    void setup() {
      gw.begin();
    
      // Send the sketch version information to the gateway and Controller
      gw.sendSketchInfo("Pressure Sensor", "1.0");
    
      BaroSensor.begin();
    
      // 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() 
    {
      if(!BaroSensor.isOK()) 
      {
        Serial.print("Sensor not Found/OK. Error: "); 
        Serial.println(BaroSensor.getError());
        BaroSensor.begin(); // Try to reinitialise the sensor if we can
      }
      
      float pressure = BaroSensor.getPressure()/100;
      float temperature = BaroSensor.getTemperature();
      if (!metric) 
      {
        // Convert to fahrenheit
        temperature = temperature * 9.0 / 5.0 + 32.0;
      }
      
      int forecast = sample(pressure);
    
      Serial.print("Temperature = ");
      Serial.print(temperature);
      Serial.println(metric?" *C":" *F");
      Serial.print("Pressure = ");
      Serial.print(pressure);
      Serial.println(" Pa");
      Serial.println(weather[forecast]);
    
    
      if (temperature != lastTemp) {
        gw.send(tempMsg.set(temperature,1));
        lastTemp = temperature;
      }
    
      if (pressure != lastPressure) {
        gw.send(pressureMsg.set(pressure, 0));
        lastPressure = pressure;
      }
    
      if (forecast != lastForecast) 
      {
        gw.send(forecastMsg.set(weather[forecast]));
        lastForecast = forecast;
      }
      
      /*
       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) {
    	// Algorithm found here
    	// http://www.freescale.com/files/sensors/doc/app_note/AN3914.pdf
    	if (minuteCount > 180)
    		minuteCount = 6;
    
    	pressureSamples[minuteCount] = pressure;
    	minuteCount++;
    
    	if (minuteCount == 5) {
    		// Avg pressure in first 5 min, value averaged from 0 to 5 min.
    		pressureAvg[0] = ((pressureSamples[1] + pressureSamples[2]
    				+ pressureSamples[3] + pressureSamples[4] + pressureSamples[5])
    				/ 5);
    	} else if (minuteCount == 35) {
    		// Avg pressure in 30 min, value averaged from 0 to 5 min.
    		pressureAvg[1] = ((pressureSamples[30] + pressureSamples[31]
    				+ pressureSamples[32] + pressureSamples[33]
    				+ pressureSamples[34]) / 5);
    		float change = (pressureAvg[1] - pressureAvg[0]);
    		if (firstRound) // first time initial 3 hour
    			dP_dt = ((65.0 / 1023.0) * 2 * change); // note this is for t = 0.5hour
    		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) {
    		// Avg pressure at end of the hour, value averaged from 0 to 5 min.
    		pressureAvg[2] = ((pressureSamples[55] + pressureSamples[56]
    				+ pressureSamples[57] + pressureSamples[58]
    				+ pressureSamples[59]) / 5);
    		float change = (pressureAvg[2] - pressureAvg[0]);
    		if (firstRound) //first time initial 3 hour
    			dP_dt = ((65.0 / 1023.0) * change); //note this is for t = 1 hour
    		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) {
    		// Avg pressure at end of the hour, value averaged from 0 to 5 min.
    		pressureAvg[3] = ((pressureSamples[90] + pressureSamples[91]
    				+ pressureSamples[92] + pressureSamples[93]
    				+ pressureSamples[94]) / 5);
    		float change = (pressureAvg[3] - pressureAvg[0]);
    		if (firstRound) // first time initial 3 hour
    			dP_dt = (((65.0 / 1023.0) * change) / 1.5); // note this is for t = 1.5 hour
    		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) {
    		// Avg pressure at end of the hour, value averaged from 0 to 5 min.
    		pressureAvg[4] = ((pressureSamples[115] + pressureSamples[116]
    				+ pressureSamples[117] + pressureSamples[118]
    				+ pressureSamples[119]) / 5);
    		float change = (pressureAvg[4] - pressureAvg[0]);
    		if (firstRound) // first time initial 3 hour
    			dP_dt = (((65.0 / 1023.0) * change) / 2); // note this is for t = 2 hour
    		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) {
    		// Avg pressure at end of the hour, value averaged from 0 to 5 min.
    		pressureAvg[5] = ((pressureSamples[150] + pressureSamples[151]
    				+ pressureSamples[152] + pressureSamples[153]
    				+ pressureSamples[154]) / 5);
    		float change = (pressureAvg[5] - pressureAvg[0]);
    		if (firstRound) // first time initial 3 hour
    			dP_dt = (((65.0 / 1023.0) * change) / 2.5); // note this is for t = 2.5 hour
    		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) {
    		// Avg pressure at end of the hour, value averaged from 0 to 5 min.
    		pressureAvg[6] = ((pressureSamples[175] + pressureSamples[176]
    				+ pressureSamples[177] + pressureSamples[178]
    				+ pressureSamples[179]) / 5);
    		float change = (pressureAvg[6] - pressureAvg[0]);
    		if (firstRound) // first time initial 3 hour
    			dP_dt = (((65.0 / 1023.0) * change) / 3); // note this is for t = 3 hour
    		else
    			dP_dt = (((65.0 / 1023.0) * 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.
    		firstRound = false; // flag to let you know that this is on the past 3 hour mark. Initialized to 0 outside main loop.
    	}
    
    	if (minuteCount < 35 && firstRound) //if time is less than 35 min on the first 3 hour interval.
    		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
    }


  • Thank you so much, it is so close. Code compiles, uploads and there is output from the serial monitor but when adding the device to Vera only a repeater node gets added and not the actual pressure sensor.

    The additional pressure sensor files have been uploaded to Vera.


  • Contest Winner

    put some delays in here... especially if you do not have the caps on the radio!!!

    BaroSensor.begin();
    // Register sensors to gw (they will be created as child devices)
    gw.sendSketchInfo("Pressure Sensor", "1.0");
    delay(250);
    gw.present(BARO_CHILD, S_BARO);
    delay(250);
    gw.present(TEMP_CHILD, S_TEMP);
    delay(250);
    metric =  gw.getConfig().isMetric;
    

    if that isn't enough, you can try to add a little more time to the delays....



  • Tried delays right up to 5000 and also added a few others but unfortunately it still only presents the repeater node to Vera


  • Contest Winner

    @Myles-L

    Try deleting the devices it created and starting over. Give it a new device number and try it without it being a repeating node:

    change:

    gw.begin();
    

    to:

    gw.begin(NULL, DEVICE_ID, false);
    

    where you defined (added) in the header of the sketch:

    #define DEVICE_ID 10 
    

    or some other number that is non-zero and not greater than 254



  • By adding those changes it went back to not outputting to the serial interface. I was able to get it to output again by removing the DEFINE DEVICE ID and the DEVICE ID section (not sure why that made a difference) but then it goes back to only adding a node to Vera.

    Really appreciate your determination to solve this and I am learning lots along the way!


  • Contest Winner

    @Myles-L

    you mind posting the code you tried last?

    Can you confirm that you have deleted the Vera devices that were created (I believe you said it was a relay)



  • I have deleted the Vera devices and I have also tried removing and re-adding the MySensors plugin in Vera. When I add the pressure sensor now it still adds as a node. Code is below:

    #include <SPI.h>
    #include <MySensor.h>
    #include <Wire.h>
    #include <BaroSensor.h>

    #define BARO_CHILD 0
    #define TEMP_CHILD 1

    unsigned long SLEEP_TIME = 60000; // Sleep time between reads (in seconds)

    MySensor gw;

    float lastPressure = -1;
    float lastTemp = -1;
    int lastForecast = -1;
    const char *weather[] = {"stable","sunny","cloudy","unstable","thunderstorm","unknown"};
    int minutes;
    float pressureSamples[180];
    int minuteCount = 0;
    bool firstRound = true;
    float pressureAvg[7];
    float dP_dt;
    boolean metric;
    MyMessage tempMsg(TEMP_CHILD, V_TEMP);
    MyMessage pressureMsg(BARO_CHILD, V_PRESSURE);
    MyMessage forecastMsg(BARO_CHILD, V_FORECAST);

    void setup() {
    gw.begin(NULL, false);

    // Send the sketch version information to the gateway and Controller
    gw.sendSketchInfo("Pressure Sensor", "1.0");
    delay(1000);
    BaroSensor.begin();
    delay(1000);
    // Register sensors to gw (they will be created as child devices)
    gw.present(BARO_CHILD, S_BARO);
    delay(1000);
    gw.present(TEMP_CHILD, S_TEMP);
    delay(1000);
    metric = gw.getConfig().isMetric;
    }

    void loop()
    {
    if(!BaroSensor.isOK())
    {
    Serial.print("Sensor not Found/OK. Error: ");
    Serial.println(BaroSensor.getError());
    BaroSensor.begin(); // Try to reinitialise the sensor if we can
    }

    float pressure = BaroSensor.getPressure()/100;
    float temperature = BaroSensor.getTemperature();
    if (!metric)
    {
    // Convert to fahrenheit
    temperature = temperature * 9.0 / 5.0 + 32.0;
    }

    int forecast = sample(pressure);

    Serial.print("Temperature = ");
    Serial.print(temperature);
    Serial.println(metric?" *C":" *F");
    Serial.print("Pressure = ");
    Serial.print(pressure);
    Serial.println(" Pa");
    Serial.println(weather[forecast]);

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

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

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

    /*
    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) {
    // Algorithm found here
    // http://www.freescale.com/files/sensors/doc/app_note/AN3914.pdf
    if (minuteCount > 180)
    minuteCount = 6;

    pressureSamples[minuteCount] = pressure;
    minuteCount++;
    
    if (minuteCount == 5) {
        // Avg pressure in first 5 min, value averaged from 0 to 5 min.
        pressureAvg[0] = ((pressureSamples[1] + pressureSamples[2]
                + pressureSamples[3] + pressureSamples[4] + pressureSamples[5])
                / 5);
    } else if (minuteCount == 35) {
        // Avg pressure in 30 min, value averaged from 0 to 5 min.
        pressureAvg[1] = ((pressureSamples[30] + pressureSamples[31]
                + pressureSamples[32] + pressureSamples[33]
                + pressureSamples[34]) / 5);
        float change = (pressureAvg[1] - pressureAvg[0]);
        if (firstRound) // first time initial 3 hour
            dP_dt = ((65.0 / 1023.0) * 2 * change); // note this is for t = 0.5hour
        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) {
        // Avg pressure at end of the hour, value averaged from 0 to 5 min.
        pressureAvg[2] = ((pressureSamples[55] + pressureSamples[56]
                + pressureSamples[57] + pressureSamples[58]
                + pressureSamples[59]) / 5);
        float change = (pressureAvg[2] - pressureAvg[0]);
        if (firstRound) //first time initial 3 hour
            dP_dt = ((65.0 / 1023.0) * change); //note this is for t = 1 hour
        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) {
        // Avg pressure at end of the hour, value averaged from 0 to 5 min.
        pressureAvg[3] = ((pressureSamples[90] + pressureSamples[91]
                + pressureSamples[92] + pressureSamples[93]
                + pressureSamples[94]) / 5);
        float change = (pressureAvg[3] - pressureAvg[0]);
        if (firstRound) // first time initial 3 hour
            dP_dt = (((65.0 / 1023.0) * change) / 1.5); // note this is for t = 1.5 hour
        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) {
        // Avg pressure at end of the hour, value averaged from 0 to 5 min.
        pressureAvg[4] = ((pressureSamples[115] + pressureSamples[116]
                + pressureSamples[117] + pressureSamples[118]
                + pressureSamples[119]) / 5);
        float change = (pressureAvg[4] - pressureAvg[0]);
        if (firstRound) // first time initial 3 hour
            dP_dt = (((65.0 / 1023.0) * change) / 2); // note this is for t = 2 hour
        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) {
        // Avg pressure at end of the hour, value averaged from 0 to 5 min.
        pressureAvg[5] = ((pressureSamples[150] + pressureSamples[151]
                + pressureSamples[152] + pressureSamples[153]
                + pressureSamples[154]) / 5);
        float change = (pressureAvg[5] - pressureAvg[0]);
        if (firstRound) // first time initial 3 hour
            dP_dt = (((65.0 / 1023.0) * change) / 2.5); // note this is for t = 2.5 hour
        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) {
        // Avg pressure at end of the hour, value averaged from 0 to 5 min.
        pressureAvg[6] = ((pressureSamples[175] + pressureSamples[176]
                + pressureSamples[177] + pressureSamples[178]
                + pressureSamples[179]) / 5);
        float change = (pressureAvg[6] - pressureAvg[0]);
        if (firstRound) // first time initial 3 hour
            dP_dt = (((65.0 / 1023.0) * change) / 3); // note this is for t = 3 hour
        else
            dP_dt = (((65.0 / 1023.0) * 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.
        firstRound = false; // flag to let you know that this is on the past 3 hour mark. Initialized to 0 outside main loop.
    }
    
    if (minuteCount < 35 && firstRound) //if time is less than 35 min on the first 3 hour interval.
        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
    

    }


  • Contest Winner

    @BulldogLowell said:

    Try this, and tell me what the serial output looks like.

    Have you added a capacitor to the radio? It could be electronic...

    #include <SPI.h>
    #include <MySensor.h>  
    #include <Wire.h>
    #include <BaroSensor.h>
    
    #define BARO_CHILD 0
    #define TEMP_CHILD 1
    #define DEVICE_ID 99
    
    unsigned long SLEEP_TIME = 60000; // Sleep time between reads (in seconds)
    
    MySensor gw;
    
    float lastPressure = -1;
    float lastTemp = -1;
    int lastForecast = -1;
    const char *weather[] = {"stable","sunny","cloudy","unstable","thunderstorm","unknown"};
    int minutes;
    float pressureSamples[180];
    int minuteCount = 0;
    bool firstRound = true;
    float pressureAvg[7];
    float dP_dt;
    boolean metric; 
    MyMessage tempMsg(TEMP_CHILD, V_TEMP);
    MyMessage pressureMsg(BARO_CHILD, V_PRESSURE);
    MyMessage forecastMsg(BARO_CHILD, V_FORECAST);
    
    void setup() {
      gw.begin(NULL, DEVICE_ID, false);
      delay(1000);
      Serial.println("Got to GW.Begin");
      // Send the sketch version information to the gateway and Controller
      gw.sendSketchInfo("Pressure Sensor", "1.0");
      Serial.println("Sketch data Presented");
      delay(1000);
      BaroSensor.begin();
      Serial.println("Brometer Sensor started...");
      delay(1000);
      // Register sensors to gw (they will be created as child devices)
      gw.present(BARO_CHILD, S_BARO);
      Serial.println("presenting Barometer");
      delay(1000);
      gw.present(TEMP_CHILD, S_TEMP);
      Serial.println("presenting Thermometer");
      delay(1000);
      metric =  gw.getConfig().isMetric;
      Serial.println("requesting Metric");
      delay(1000);
      Serial.println("Setup Complete");
    }
    
    void loop() 
    {
    }


  • The Sensor and Ethernet gateway both have 4.7uf electrolytic capacitors across the power input of the radio's (I cant get much distance out of them, maybe <10 metres, but they do work for the relay sensor).

    The serial output looks like this: ��Ah���Y5����������i��`q!���J�����



  • Using that sketch I was able to add it to Vera, it just does not report pressure or forecast (obviously as there is no data being presented to it)


  • Contest Winner

    Great, now just plug the loop() back into the sketch, flash your arduino, and you should be good to go

    oh... and add a Serial.begin(yourDesiredBaudRate) to setup() ;)


Log in to reply
 

Looks like your connection to MySensors Forum was lost, please wait while we try to reconnect.