public void CalculateBarometricPressureWithHumidity(double measuredValue, double temperature, double altitude, double relativeHumidity,
double expected)
{
var result = WeatherHelper.CalculateBarometricPressure(Pressure.FromHectopascal(measuredValue),
Temperature.FromCelsius(temperature), altitude, relativeHumidity);
Assert.Equal(expected, result.Hectopascal, 2);
}
public void CalculateBarometricPressureWithHumidity(double measuredValue, double temperature, double altitude, double relativeHumidity,
double expected)
{
var result = WeatherHelper.CalculateBarometricPressure(Pressure.FromHectopascals(measuredValue),
Temperature.FromDegreesCelsius(temperature), Length.FromMeters(altitude), Ratio.FromPercent(relativeHumidity));
Assert.Equal(expected, result.Hectopascals, 2);
}
[InlineData(950, 15, 546.89, 1012.9)] // result is changed to 1012.9 from 1013.23
public void CalculateBarometricPressure(double measuredValue, double temperature, double altitude,
double expected)
{
Pressure result = WeatherHelper.CalculateBarometricPressure(Pressure.FromHectopascals(measuredValue),
Temperature.FromDegreesCelsius(temperature), Length.FromMeters(altitude));
Assert.Equal(expected, result.Hectopascals, 2);
}
/// <inheritdoc/>
public override ISensorSample TakeReading(WeatherObservation observation)
{
this.LogTakeReadingStart();
var sensorResult = new SensorSample(this.SensorName);
var result = this.sensor.Read();
if (result.Humidity.HasValue && result.Pressure.HasValue && result.Temperature.HasValue)
{
var pressure = result.Pressure.Value;
var temperature = new Temperature(result.Temperature.Value.DegreesCelsius + this.calibrationOffset, UnitsNet.Units.TemperatureUnit.DegreeCelsius);
var rawTemperature = result.Temperature.Value;
var humidity = result.Humidity.Value;
var actualAltitude = new Length(this.altitudeInMeters, UnitsNet.Units.LengthUnit.Meter);
var calculatedAltitude = WeatherHelper.CalculateAltitude(pressure, WeatherHelper.MeanSeaLevel, rawTemperature);
double absHumidity = WeatherHelper.CalculateAbsoluteHumidity(temperature, humidity).GramsPerCubicMeter;
double dewPoint = WeatherHelper.CalculateDewPoint(temperature, humidity).DegreesCelsius;
double heatIndex = WeatherHelper.CalculateHeatIndex(temperature, humidity).DegreesCelsius;
double vapourPressure = WeatherHelper.CalculateActualVaporPressure(temperature, humidity).Hectopascals;
double barometricPressure = WeatherHelper.CalculateBarometricPressure(pressure, temperature, actualAltitude, humidity).Hectopascals;
double vapourPressureOverIce = WeatherHelper.CalculateSaturatedVaporPressureOverIce(temperature).Hectopascals;
double vapourPressureOverWater = WeatherHelper.CalculateSaturatedVaporPressureOverWater(temperature).Hectopascals;
double seaLevelPressure = WeatherHelper.CalculateSeaLevelPressure(pressure, actualAltitude, temperature).Hectopascals;
sensorResult.AddFinalObservation(temperature.DegreesCelsius, "TEMPERATURE", ObservationUnits.DegreesCelcius);
sensorResult.AddFinalObservation(pressure.Hectopascals, "PRESSURE", ObservationUnits.HectoPascal);
sensorResult.AddFinalObservation(barometricPressure, "BAROMETRIC PRESSURE", ObservationUnits.HectoPascal);
sensorResult.AddFinalObservation(seaLevelPressure, "SEA LEVEL PRESSURE", ObservationUnits.HectoPascal);
sensorResult.AddFinalObservation(vapourPressureOverIce, "OVER ICE PRESSURE", ObservationUnits.HectoPascal);
sensorResult.AddFinalObservation(vapourPressureOverWater, "OVER WATER PRESSURE", ObservationUnits.HectoPascal);
sensorResult.AddFinalObservation(humidity.Percent, "RELATIVE HUMIDITY", ObservationUnits.Percentage);
sensorResult.AddFinalObservation(absHumidity, "ABSOLUTE HUMIDITY", ObservationUnits.GramsPerCubicMeter);
sensorResult.AddFinalObservation(vapourPressure, "VAPOUR PRESSURE", ObservationUnits.HectoPascal);
sensorResult.AddFinalObservation(calculatedAltitude.Meters, "CALCULATED ALTITUDE", ObservationUnits.Meters);
sensorResult.AddFinalObservation(actualAltitude.Meters, "ACTUAL ALTITUDE", ObservationUnits.Meters);
sensorResult.AddFinalObservation(heatIndex, "HEAT INDEX", ObservationUnits.DegreesCelcius);
sensorResult.AddFinalObservation(dewPoint, "DEW POINT", ObservationUnits.DegreesCelcius);
observation.Temperature1 = temperature.DegreesCelsius;
observation.Pressure = pressure.Hectopascals;
observation.BarometricPressure = barometricPressure;
observation.SealevelPressure = seaLevelPressure;
observation.OverIcePressure = vapourPressureOverIce;
observation.OverWaterPressure = vapourPressureOverWater;
observation.RelativeHumidity = humidity.Percent;
observation.AbsoluteHumidity = absHumidity;
observation.ActualAltitude = actualAltitude.Meters;
observation.CalculatedAltitude = calculatedAltitude.Meters;
observation.HeatIndex = heatIndex;
observation.DewPoint = dewPoint;
}
this.LogTakeReadingComplete();
return(sensorResult);
}
public static void DisplayModes(ArduinoBoard board)
{
const int Gpio2 = 2;
const int MaxMode = 10;
Length stationAltitude = Length.FromMeters(650);
int mode = 0;
var gpioController = board.CreateGpioController();
gpioController.OpenPin(Gpio2);
gpioController.SetPinMode(Gpio2, PinMode.Input);
CharacterDisplay disp = new CharacterDisplay(board);
Console.WriteLine("Display output test");
Console.WriteLine("The button on GPIO 2 changes modes");
Console.WriteLine("Press x to exit");
disp.Output.ScrollUpDelay = TimeSpan.FromMilliseconds(500);
AutoResetEvent buttonClicked = new AutoResetEvent(false);
void ChangeMode(object sender, PinValueChangedEventArgs pinValueChangedEventArgs)
{
mode++;
if (mode > MaxMode)
{
// Don't change back to 0
mode = 1;
}
buttonClicked.Set();
}
gpioController.RegisterCallbackForPinValueChangedEvent(Gpio2, PinEventTypes.Falling, ChangeMode);
var device = board.CreateI2cDevice(new I2cConnectionSettings(0, Bmp280.DefaultI2cAddress));
Bmp280?bmp;
try
{
bmp = new Bmp280(device);
bmp.StandbyTime = StandbyTime.Ms250;
bmp.SetPowerMode(Bmx280PowerMode.Normal);
}
catch (IOException)
{
bmp = null;
Console.WriteLine("BMP280 not available");
}
OpenHardwareMonitor hardwareMonitor = new OpenHardwareMonitor();
hardwareMonitor.EnableDerivedSensors();
TimeSpan sleeptime = TimeSpan.FromMilliseconds(500);
string modeName = string.Empty;
string previousModeName = string.Empty;
int firstCharInText = 0;
while (true)
{
if (Console.KeyAvailable && Console.ReadKey(true).KeyChar == 'x')
{
break;
}
// Default
sleeptime = TimeSpan.FromMilliseconds(500);
switch (mode)
{
case 0:
modeName = "Display ready";
disp.Output.ReplaceLine(1, "Button for mode");
// Just text
break;
case 1:
{
modeName = "Time";
disp.Output.ReplaceLine(1, DateTime.Now.ToLongTimeString());
sleeptime = TimeSpan.FromMilliseconds(200);
break;
}
case 2:
{
modeName = "Date";
disp.Output.ReplaceLine(1, DateTime.Now.ToShortDateString());
break;
}
case 3:
modeName = "Temperature / Barometric Pressure";
if (bmp != null && bmp.TryReadTemperature(out Temperature temp) && bmp.TryReadPressure(out Pressure p2))
{
Pressure p3 = WeatherHelper.CalculateBarometricPressure(p2, temp, stationAltitude);
disp.Output.ReplaceLine(1, string.Format(CultureInfo.CurrentCulture, "{0:s1} {1:s1}", temp, p3));
}
/// <inheritdoc/>
public override void Initialize()
{
this.LogStartInitialization();
this.i2cDevice = this.Controller.GetI2CConnection(this.DeviceId);
this.sensor = new Bme280(this.i2cDevice)
{
TemperatureSampling = Sampling.LowPower,
PressureSampling = Sampling.UltraHighResolution,
HumiditySampling = Sampling.Standard,
};
var readResult = this.sensor.ReadStatus();
this.LogMessage($"BME280 status {readResult}");
var result = this.sensor.Read();
if (result.Humidity.HasValue && result.Pressure.HasValue && result.Temperature.HasValue)
{
var pressure = result.Pressure.Value;
var temperature = new Temperature(result.Temperature.Value.DegreesCelsius - this.calibrationOffset, UnitsNet.Units.TemperatureUnit.DegreeCelsius);
var humidity = result.Humidity.Value;
var actualAltitude = new Length(this.altitudeInMeters, UnitsNet.Units.LengthUnit.Meter);
var calculatedAltitude = WeatherHelper.CalculateAltitude(pressure, WeatherHelper.MeanSeaLevel, temperature);
double absHumidity = WeatherHelper.CalculateAbsoluteHumidity(temperature, humidity).GramsPerCubicMeter;
double dewPoint = WeatherHelper.CalculateDewPoint(temperature, humidity).DegreesCelsius;
double heatIndex = WeatherHelper.CalculateHeatIndex(temperature, humidity).DegreesCelsius;
double vapourPressure = WeatherHelper.CalculateActualVaporPressure(temperature, humidity).Hectopascals;
double barometricPressure = WeatherHelper.CalculateBarometricPressure(pressure, temperature, actualAltitude, humidity).Hectopascals;
double vapourPressureOverIce = WeatherHelper.CalculateSaturatedVaporPressureOverIce(temperature).Hectopascals;
double vapourPressureOverWater = WeatherHelper.CalculateSaturatedVaporPressureOverWater(temperature).Hectopascals;
double seaLevelPressure = WeatherHelper.CalculateSeaLevelPressure(pressure, actualAltitude, temperature).Hectopascals;
this.LogMessage($"Temperature: {temperature.DegreesCelsius:0.#}\u00B0C");
this.LogMessage($"Pressure: {pressure.Hectopascals:0.##}hPa");
this.LogMessage($"Barometric Pressure: {barometricPressure:0.##}hPa");
this.LogMessage($"Sea level Pressure: {seaLevelPressure:0.##}hPa");
this.LogMessage($"Over ice Pressure: {vapourPressureOverIce:0.##}hPa");
this.LogMessage($"Over water Pressure: {vapourPressureOverWater:0.##}hPa");
this.LogMessage($"Relative humidity: {humidity.Percent:0.#}%");
this.LogMessage($"Absolute humidity: {absHumidity:0.#}g/m3");
this.LogMessage($"Vapour pressure: {vapourPressure:0.#}hPa");
this.LogMessage($"Calculate altitude: {calculatedAltitude.Meters:0.##}m");
this.LogMessage($"Actual altitude: {actualAltitude.Meters:0.##}m");
this.LogMessage($"Heat index: {heatIndex:0.#}\u00B0C");
this.LogMessage($"Dew point: {dewPoint:0.#}\u00B0C");
Thread.Sleep(1000);
// set sane defaults
this.sensor.TemperatureSampling = Sampling.UltraLowPower;
this.sensor.PressureSampling = Sampling.UltraLowPower;
this.sensor.HumiditySampling = Sampling.UltraLowPower;
this.sensor.FilterMode = Bmx280FilteringMode.Off;
this.sensor.SetPowerMode(Iot.Device.Bmxx80.PowerMode.Bmx280PowerMode.Forced);
this.IsInitialized = true;
this.LogStartSuccess();
}
this.LogError("Couldn't read from BME280");
}
/// <summary>
/// Entry point for example program
/// </summary>
/// <param name="args">Command line arguments</param>
public static void StartBmp(string[] args)
{
Console.WriteLine("Hello Bmp280!");
Length stationHeight = Length.FromMeters(640); // Elevation of the sensor
// bus id on the raspberry pi 3 and 4
const int busId = 1;
// set this to the current sea level pressure in the area for correct altitude readings
var defaultSeaLevelPressure = WeatherHelper.MeanSeaLevel;
var i2cSettings = new I2cConnectionSettings(busId, Bmp280.DefaultI2cAddress);
var i2cDevice = I2cDevice.Create(i2cSettings);
var i2CBmp280 = new Bmp280(i2cDevice);
using (i2CBmp280)
{
while (true)
{
// set higher sampling
i2CBmp280.TemperatureSampling = Sampling.LowPower;
i2CBmp280.PressureSampling = Sampling.UltraHighResolution;
// set mode forced so device sleeps after read
i2CBmp280.SetPowerMode(Bmx280PowerMode.Forced);
// wait for measurement to be performed
var measurementTime = i2CBmp280.GetMeasurementDuration();
Thread.Sleep(measurementTime);
// read values
i2CBmp280.TryReadTemperature(out var tempValue);
Console.WriteLine($"Temperature: {tempValue.DegreesCelsius} \u00B0C");
i2CBmp280.TryReadPressure(out var preValue);
Console.WriteLine($"Pressure: {preValue.Hectopascals} hPa");
// Note that if you already have the pressure value and the temperature, you could also calculate altitude by using
// double altValue = WeatherHelper.CalculateAltitude(preValue, defaultSeaLevelPressure, tempValue) which would be more performant.
i2CBmp280.TryReadAltitude(out var altValue);
Console.WriteLine($"Calculated Altitude: {altValue} m");
Thread.Sleep(1000);
// change sampling rate
i2CBmp280.TemperatureSampling = Sampling.UltraHighResolution;
i2CBmp280.PressureSampling = Sampling.UltraLowPower;
i2CBmp280.FilterMode = Bmx280FilteringMode.X4;
// set mode forced and read again
i2CBmp280.SetPowerMode(Bmx280PowerMode.Forced);
// wait for measurement to be performed
measurementTime = i2CBmp280.GetMeasurementDuration();
Thread.Sleep(measurementTime);
// read values
i2CBmp280.TryReadTemperature(out tempValue);
Console.WriteLine($"Temperature: {tempValue.DegreesCelsius} \u00B0C");
i2CBmp280.TryReadPressure(out preValue);
Console.WriteLine($"Pressure: {preValue.Hectopascals} hPa");
// This time use altitude calculation
altValue = WeatherHelper.CalculateAltitude(preValue, defaultSeaLevelPressure, tempValue);
Console.WriteLine($"Calculated Altitude: {altValue} m");
// Calculate the barometric (corrected) pressure for the local position.
// Change the stationHeight value above to get a correct reading, but do not be tempted to insert
// the value obtained from the formula above. Since that estimates the altitude based on pressure,
// using that altitude to correct the pressure won't work.
var correctedPressure = WeatherHelper.CalculateBarometricPressure(preValue, tempValue, stationHeight);
Console.WriteLine($"Pressure corrected for altitude {stationHeight.Meters} m (with average humidity): {correctedPressure.Hectopascals} hPa");
Thread.Sleep(5000);
}
}
}
/// <inheritdoc/>
public override ISensorSample TakeReading(WeatherObservation observation)
{
this.LogTakeReadingStart();
var sensorResult = new SensorSample(this.SensorName);
// Initialize for reading
this.Device.Write(new byte[] { REGCONTROLHUM, OVERSAMPLEHUM });
var control = GetControlCode();
this.Device.Write(new byte[] { REGCONTROL, (byte)control });
// Read calibaration data
var cal1 = this.ReadBytes(0x88, 24);
var cal2 = this.ReadBytes(0xA1, 1);
var cal3 = this.ReadBytes(0xE1, 7);
sensorResult.AddDiagnostic("Calibration data (1/2/3)");
sensorResult.AddDiagnostic(ByteOperations.PrintByteArray(cal1));
sensorResult.AddDiagnostic(ByteOperations.PrintByteArray(cal2));
sensorResult.AddDiagnostic(ByteOperations.PrintByteArray(cal3));
var calibrationData = ExtractcalibrationData(cal1, cal2, cal3);
// Pause per spec
var wait_time = GetWaitTime();
Thread.Sleep((int)wait_time / 1000);
// Read raw data
var data = this.ReadBytes(REGDATA, 8);
sensorResult.AddDiagnostic("Raw data");
sensorResult.AddDiagnostic(ByteOperations.PrintByteArray(data));
var rawTemp = (data[3] << 12) | (data[4] << 4) | (data[5] >> 4);
double rawTemperature = CalculateTemperature(sensorResult, calibrationData, rawTemp, out double tFine);
// Refine pressure and adjust for temperature
var rawPressure = (data[0] << 12) | (data[1] << 4) | (data[2] >> 4);
double pressureValue = CalculatePressure(sensorResult, calibrationData, rawPressure, tFine);
// Refine humidity
var rawHumidity = (data[6] << 8) | data[7];
double humidityValue = CalculateHumidity(sensorResult, calibrationData, rawHumidity, tFine);
sensorResult.AddFinalObservation(rawTemperature + this.calibrationOffset, "TEMPERATURE", ObservationUnits.DegreesCelcius);
sensorResult.AddFinalObservation(pressureValue, "PRESSURE", ObservationUnits.HectoPascal);
sensorResult.AddFinalObservation(humidityValue, "HUMIDITY", ObservationUnits.Percentage);
var pressure = new Pressure(pressureValue, UnitsNet.Units.PressureUnit.Hectopascal);
var humidity = new RelativeHumidity(humidityValue, UnitsNet.Units.RelativeHumidityUnit.Percent);
var temperature = new Temperature(rawTemperature, UnitsNet.Units.TemperatureUnit.DegreeCelsius);
var actualAltitude = new Length(this.altitudeInMeters, UnitsNet.Units.LengthUnit.Meter);
var altitudeCalculated = WeatherHelper.CalculateAltitude(pressure);
double absHumidity = WeatherHelper.CalculateAbsoluteHumidity(temperature, humidity).GramsPerCubicMeter;
double dewPoint = WeatherHelper.CalculateDewPoint(temperature, humidity).DegreesCelsius;
double heatIndex = WeatherHelper.CalculateHeatIndex(temperature, humidity).DegreesCelsius;
double vapourPressure = WeatherHelper.CalculateActualVaporPressure(temperature, humidity).Hectopascals;
double barometricPressure = WeatherHelper.CalculateBarometricPressure(pressure, temperature, actualAltitude, humidity).Hectopascals;
double vapourPressureOverIce = WeatherHelper.CalculateSaturatedVaporPressureOverIce(temperature).Hectopascals;
double vapourPressureOverWater = WeatherHelper.CalculateSaturatedVaporPressureOverWater(temperature).Hectopascals;
double seaLevelPressure = WeatherHelper.CalculateSeaLevelPressure(pressure, actualAltitude, temperature).Hectopascals;
sensorResult.AddFinalObservation(temperature.DegreesCelsius + this.calibrationOffset, "TEMPERATURE", ObservationUnits.DegreesCelcius);
sensorResult.AddFinalObservation(pressure.Hectopascals, "PRESSURE", ObservationUnits.HectoPascal);
sensorResult.AddFinalObservation(barometricPressure, "BAROMETRIC PRESSURE", ObservationUnits.HectoPascal);
sensorResult.AddFinalObservation(seaLevelPressure, "SEA LEVEL PRESSURE", ObservationUnits.HectoPascal);
sensorResult.AddFinalObservation(vapourPressureOverIce, "OVER ICE PRESSURE", ObservationUnits.HectoPascal);
sensorResult.AddFinalObservation(vapourPressureOverWater, "OVER WATER PRESSURE", ObservationUnits.HectoPascal);
sensorResult.AddFinalObservation(humidity.Percent, "RELATIVE HUMIDITY", ObservationUnits.Percentage);
sensorResult.AddFinalObservation(absHumidity, "ABSOLUTE HUMIDITY", ObservationUnits.GramsPerCubicMeter);
sensorResult.AddFinalObservation(vapourPressure, "VAPOUR PRESSURE", ObservationUnits.Percentage);
sensorResult.AddFinalObservation(altitudeCalculated.Meters, "CALCULATED ALTITUDE", ObservationUnits.Meters);
sensorResult.AddFinalObservation(actualAltitude.Meters, "ACTUAL ALTITUDE", ObservationUnits.Meters);
sensorResult.AddFinalObservation(heatIndex, "HEAT INDEX", ObservationUnits.DegreesCelcius);
sensorResult.AddFinalObservation(dewPoint, "DEW POINT", ObservationUnits.DegreesCelcius);
observation.Temperature1 = temperature.DegreesCelsius + this.calibrationOffset;
observation.Pressure = pressure.Hectopascals;
observation.BarometricPressure = barometricPressure;
observation.SealevelPressure = seaLevelPressure;
observation.OverIcePressure = vapourPressureOverIce;
observation.OverWaterPressure = vapourPressureOverWater;
observation.RelativeHumidity = humidity.Percent;
observation.AbsoluteHumidity = absHumidity;
observation.ActualAltitude = actualAltitude.Meters;
observation.CalculatedAltitude = altitudeCalculated.Meters;
observation.HeatIndex = heatIndex;
observation.DewPoint = dewPoint;
this.LogTakeReadingComplete();
return(sensorResult);
}