Use floating point precision for measurement compensations to yield sensor resolution
According to the datasheet the resolution delivered by the sensor is better than 1 degree Celsius, 1 Pascal, 1 percent relative humidity etc. The user should have the possibility to get floating point precision and figure out what the measurement accuracy allows given their settings.
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Christian Nicolai
parent
db02dd0d65
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6442510ab0
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@ -315,68 +315,68 @@ class BME680(BME680Data):
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def _calc_temperature(self, temperature_adc):
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"""Convert the raw temperature to degrees C using calibration_data."""
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var1 = (temperature_adc >> 3) - (self.calibration_data.par_t1 << 1)
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var2 = (var1 * self.calibration_data.par_t2) >> 11
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var3 = ((var1 >> 1) * (var1 >> 1)) >> 12
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var3 = ((var3) * (self.calibration_data.par_t3 << 4)) >> 14
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var1 = (temperature_adc / 8.0) - (self.calibration_data.par_t1 * 2.0)
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var2 = (var1 * self.calibration_data.par_t2) / 2048.0
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var3 = ((var1 / 2.0) * (var1 / 2.0)) / 4096.0
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var3 = ((var3) * (self.calibration_data.par_t3 * 16.0)) / 16384.0
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# Save teperature data for pressure calculations
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self.calibration_data.t_fine = (var2 + var3) + self.offset_temp_in_t_fine
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calc_temp = (((self.calibration_data.t_fine * 5) + 128) >> 8)
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calc_temp = (((self.calibration_data.t_fine * 5.0) + 128.0) / 256.0)
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return calc_temp
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def _calc_pressure(self, pressure_adc):
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"""Convert the raw pressure using calibration data."""
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var1 = ((self.calibration_data.t_fine) >> 1) - 64000
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var2 = ((((var1 >> 2) * (var1 >> 2)) >> 11) *
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self.calibration_data.par_p6) >> 2
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var2 = var2 + ((var1 * self.calibration_data.par_p5) << 1)
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var2 = (var2 >> 2) + (self.calibration_data.par_p4 << 16)
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var1 = (((((var1 >> 2) * (var1 >> 2)) >> 13) *
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((self.calibration_data.par_p3 << 5)) >> 3) +
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((self.calibration_data.par_p2 * var1) >> 1))
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var1 = var1 >> 18
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var1 = (self.calibration_data.t_fine / 2.0) - 64000.0
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var2 = ((((var1 / 4.0) * (var1 / 4.0)) / 2048.0) *
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self.calibration_data.par_p6) / 4.0
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var2 = var2 + ((var1 * self.calibration_data.par_p5) * 2.0)
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var2 = (var2 / 4.0) + (self.calibration_data.par_p4 * 65536.0)
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var1 = (((((var1 / 4.0) * (var1 / 4.0)) / 8192.0) *
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((self.calibration_data.par_p3 * 32.0)) / 8.0) +
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((self.calibration_data.par_p2 * var1) / 2.0))
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var1 = var1 / 262144.0
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var1 = ((32768 + var1) * self.calibration_data.par_p1) >> 15
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calc_pressure = 1048576 - pressure_adc
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calc_pressure = ((calc_pressure - (var2 >> 12)) * (3125))
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var1 = ((32768.0 + var1) * self.calibration_data.par_p1) / 32768.0
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calc_pressure = 1048576.0 - pressure_adc
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calc_pressure = ((calc_pressure - (var2 / 4096.0)) * (3125.0))
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if calc_pressure >= (1 << 31):
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calc_pressure = ((calc_pressure // var1) << 1)
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calc_pressure = ((calc_pressure / var1) * 2.0)
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else:
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calc_pressure = ((calc_pressure << 1) // var1)
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calc_pressure = ((calc_pressure * 2.0) / var1)
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var1 = (self.calibration_data.par_p9 * (((calc_pressure >> 3) *
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(calc_pressure >> 3)) >> 13)) >> 12
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var2 = ((calc_pressure >> 2) *
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self.calibration_data.par_p8) >> 13
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var3 = ((calc_pressure >> 8) * (calc_pressure >> 8) *
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(calc_pressure >> 8) *
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self.calibration_data.par_p10) >> 17
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var1 = (self.calibration_data.par_p9 * (((calc_pressure / 8.0) *
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(calc_pressure / 8.0)) / 8192.0)) / 4096.0
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var2 = ((calc_pressure / 4.0) *
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self.calibration_data.par_p8) / 8192.0
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var3 = ((calc_pressure / 256.0) * (calc_pressure / 256.0) *
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(calc_pressure / 256.0) *
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self.calibration_data.par_p10) / 131072.0
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calc_pressure = (calc_pressure) + ((var1 + var2 + var3 +
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(self.calibration_data.par_p7 << 7)) >> 4)
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(self.calibration_data.par_p7 * 128.0)) / 16.0)
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return calc_pressure
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def _calc_humidity(self, humidity_adc):
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"""Convert the raw humidity using calibration data."""
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temp_scaled = ((self.calibration_data.t_fine * 5) + 128) >> 8
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var1 = (humidity_adc - ((self.calibration_data.par_h1 * 16))) -\
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(((temp_scaled * self.calibration_data.par_h3) // (100)) >> 1)
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temp_scaled = ((self.calibration_data.t_fine * 5.0) + 128.0) / 256.0
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var1 = (humidity_adc - ((self.calibration_data.par_h1 * 16.0))) -\
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(((temp_scaled * self.calibration_data.par_h3) / (100.0)) / 2.0)
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var2 = (self.calibration_data.par_h2 *
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(((temp_scaled * self.calibration_data.par_h4) // (100)) +
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(((temp_scaled * ((temp_scaled * self.calibration_data.par_h5) // (100))) >> 6) //
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(100)) + (1 * 16384))) >> 10
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(((temp_scaled * self.calibration_data.par_h4) / (100.0)) +
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(((temp_scaled * ((temp_scaled * self.calibration_data.par_h5) / (100.0))) / 64.0) /
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(100.0)) + (1.0 * 16384.0))) / 1024.0
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var3 = var1 * var2
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var4 = self.calibration_data.par_h6 << 7
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var4 = ((var4) + ((temp_scaled * self.calibration_data.par_h7) // (100))) >> 4
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var5 = ((var3 >> 14) * (var3 >> 14)) >> 10
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var6 = (var4 * var5) >> 1
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calc_hum = (((var3 + var6) >> 10) * (1000)) >> 12
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var4 = self.calibration_data.par_h6 * 128.0
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var4 = ((var4) + ((temp_scaled * self.calibration_data.par_h7) / (100.0))) / 16.0
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var5 = ((var3 / 16384.0) * (var3 / 16384.0)) / 1024.0
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var6 = (var4 * var5) / 2.0
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calc_hum = (((var3 + var6) / 1024.0) * (1000.0)) / 4096.0
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return min(max(calc_hum, 0), 100000)
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return min(max(calc_hum, 0.0), 100000.0)
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def _calc_gas_resistance(self, gas_res_adc, gas_range):
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"""Convert the raw gas resistance using calibration data."""
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