Merge branch 'ayeks-offset'

examples/temp-offset.py

@@ -0,0 +1,39 @@
+#!/usr/bin/env python
+import bme680
+
+print("""Display Temperature, Pressure and Humidity with different offsets.
+""")
+
+sensor = bme680.BME680()
+
+# These oversampling settings can be tweaked to
+# change the balance between accuracy and noise in
+# the data.
+
+sensor.set_humidity_oversample(bme680.OS_2X)
+sensor.set_pressure_oversample(bme680.OS_4X)
+sensor.set_temperature_oversample(bme680.OS_8X)
+sensor.set_filter(bme680.FILTER_SIZE_3)
+
+def display_data(offset=0):
+    sensor.set_temp_offset(offset)
+    sensor.get_sensor_data()
+    output = "{0:.2f} C, {1:.2f} hPa, {2:.3f} %RH".format(sensor.data.temperature, sensor.data.pressure, sensor.data.humidity)
+    print(output)
+    print("")
+
+print("Initial readings")
+display_data()
+
+print("SET offset 4 degrees celsius")
+display_data(4)
+
+print("SET offset -1.87 degrees celsius")
+display_data(-1.87)
+
+print("SET offset -100 degrees celsius")
+display_data(-100)
+
+print("SET offset 0 degrees celsius")
+display_data(0)
+

library/LICENSE.txt

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2018 Pimoroni Ltd
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

library/MANIFEST.in

@@ -2,4 +2,4 @@ include CHANGELOG.txt
 include LICENSE.txt
 include README.txt
 include setup.py
-include bme680.py
+recursive-include bme680 *.py

library/bme680/__init__.py

@@ -36,7 +36,7 @@ class BME680(BME680Data):
         self.set_temperature_oversample(OS_8X)
         self.set_filter(FILTER_SIZE_3)
         self.set_gas_status(ENABLE_GAS_MEAS)
-
+        self.set_temp_offset(0)
         self.get_sensor_data()
 
     def _get_calibration_data(self):
@@ -56,6 +56,17 @@ class BME680(BME680Data):
         self._set_regs(SOFT_RESET_ADDR, SOFT_RESET_CMD) 
         time.sleep(RESET_PERIOD / 1000.0)
 
+    def set_temp_offset(self, value):
+        """Set temperature offset in celsius
+
+        If set, the temperature t_fine will be increased by given value in celsius.
+        :param value: Temperature offset in Celsius, eg. 4, -8, 1.25
+        """
+        if value == 0:
+            self.offset_temp_in_t_fine = 0
+        else:
+            self.offset_temp_in_t_fine = int(math.copysign((((int(abs(value) * 100)) << 8) - 128) / 5, value))
+
     def set_humidity_oversample(self, value):
         """Set humidity oversampling
         
@@ -293,7 +304,7 @@ class BME680(BME680Data):
         var3 = ((var3) * (self.calibration_data.par_t3 << 4)) >> 14
 
         # Save teperature data for pressure calculations
-        self.calibration_data.t_fine = (var2 + var3)
+        self.calibration_data.t_fine = (var2 + var3) + self.offset_temp_in_t_fine
         calc_temp = (((self.calibration_data.t_fine * 5) + 128) >> 8)
 
         return calc_temp