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mirror of https://github.com/cmur2/python-bme680.git synced 2024-11-15 04:56:20 +01:00
python-bme680/bme680/__init__.py
2017-10-15 11:29:51 +01:00

128 lines
4.9 KiB
Python

from . import constants
import math
class BME680(constants.BME680):
def __init__(self):
constants.BME680.__init__(self)
def init(self):
pass
def soft_reset(self):
pass
def set_sensor_mode(self):
pass
def get_sensor_mode(self, mode):
pass
def set_profile_duration(self, duration):
pass
def get_profile_duration(self):
pass
def _get_sensor_data(self):
pass
def _get_regs(self, addr, length):
pass
def _get_calibration_data(self):
calibration = self._get_regs(constants.COEFF_ADDR1, constants.COEFF_ADDR1_LEN)
calibration += self._get_regs(constants.COEFF_ADDR2, constants.COEFF_ADDR2_LEN)
heat_range = self._get_regs(constants.ADDR_RES_HEAT_RANGE_ADDR, 1)[0]
heat_value = self._get_regs(constants.ADDR_RES_HEAT_VAL_ADDR, 1)[0]
sw_error = self._get_regs(constants.ADDR_RANGE_SW_ERR_ADDR, 1)[0]
self.calibration_data.set_from_array(calibration)
self.calibration_data.set_other(heat_range, heat_value, sw_error)
def _calc_temperature(self, temperature_adc):
var1 = (temperature_adc / 8) - (self.calibration_data.par_t1 * 2)
var2 = (var1 * self.calibration_data.par_t2) / 2048
var3 = ((var1 / 2) * (var1 / 2)) / 4096
var3 = ((var3) * (self.calibration_data.par_t3 * 16)) / 16384
# Save teperature data for pressure calculations
self.calibration_data.t_fine = (var2 + var3)
calc_temp = (((self.calibration_data.t_fine * 5) + 128) / 256)
return calc_temp
def _calc_pressure(self, pressure_adc):
var1 = (self.calibration_data.t_fine / 2) - 64000
var2 = ((var1 / 4) * (var1 / 4)) / 2048
var2 = (var2 * self.calibration_data.par_p6) / 4
var2 = var2 + ((var1 * self.calibration_data.par_p5) * 2)
var2 = (var2 / 4) + (self.calibration_data.par_p4 * 65536)
var1 = ((var1 / 4) * (var1 / 4)) / 8192
var1 = ((var1 * (self.calibration_data.par_p3 * 32)) / 8) + ((self.calibration_data.par_p2 * var1) / 2)
var1 = var1 / 262144
var1 = ((32768 + var1) * self.calibration_data.par_p1) / 32768
calc_pres = 1048576 - pressure_adc
calc_pres = (calc_pres - (var2 / 4096)) * 3125
calc_pres = (calc_pres / var1) * 2
var1 = (self.calibration_data.par_p9 * (((calc_pres / 8) * (calc_pres / 8)) / 8192)) / 4096
var2 = ((calc_pres / 4) * self.calibration_data.par_p8) / 8192
var3 = ((calc_pres / 256)
* (calc_pres / 256)
* (calc_pres / 256)
* self.calibration_data.par_p10) / 131072
calc_pres = calc_pres + ((var1 + var2 + var3 + (self.calibration_data.par_p7 * 128)) / 16)
return calc_pres
def _calc_humidity(self, humidity_adc):
temp_scaled = ((self.calibration_data.t_fine * 5) + 128) / 256
var1 = (humidity_adc - ((self.calibration_data.par_h1 * 16))) \
- (((temp_scaled * self.calibration_data.par_h3) / (100)) / 2)
var2 = (self.calibration_data.par_h2
* (((temp_scaled * self.calibration_data.par_h4) / (100))
+ (((temp_scaled * ((temp_scaled * self.calibration_data.par_h5) / (100))) / 64)
/ (100)) + (1 * 16384))) / 1024
var3 = var1 * var2
var4 = self.calibration_data.par_h6 * 128
var4 = ((var4) + ((temp_scaled * self.calibration_data.par_h7) / (100))) / 16
var5 = ((var3 / 16384) * (var3 / 16384)) / 1024
var6 = (var4 * var5) / 2
calc_hum = (((var3 + var6) / 1024) * (1000)) / 4096
return min(max(calc_hum,0),100000)
def _calc_gas_resistance(self, gas_res_adc, gas_range):
var1 = ((1340 + (5 * self.calibration_data.range_sw_err)) * (constants.lookupTable1[gas_range])) / 65536
var2 = (((gas_res_adc * 32768) - (16777216)) + var1)
var3 = ((constants.lookupTable2[gas_range] * var1) / 512)
calc_gas_res = ((var3 + (var2 / 2)) / var2)
return calc_gas_res
def _calc_heater_resistance(self, temperature):
temperature = min(max(temperature,200),400)
var1 = ((self.ambient_temperature * self.calibration_data.par_gh3) / 1000) * 256
var2 = (self.calibration_data.par_gh1 + 784) * (((((self.calibration_data.par_gh2 + 154009) * temperature * 5) / 100) + 3276800) / 10)
var3 = var1 + (var2 / 2)
var4 = (var3 / (self.calibration_data.res_heat_range + 4))
var5 = (131 * self.calibration_data.res_heat_val) + 65536
heatr_res_x100 = (((var4 / var5) - 250) * 34)
heatr_res = ((heatr_res_x100 + 50) / 100)
return int(heatr_res)
def _calc_heater_duration(self, duration):
if duration < 0xfc0:
factor = 0
while duration > 0x3f:
duration /= 4
factor += 1
return int(duration + (factor * 64))
return 0xff