Merge pull request #9 from caternuson/iss8

Add altitude property

Author: tannewt

adafruit_dps310.py

@@ -45,6 +45,7 @@
 __repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_DPS310.git"
 
 # Common imports; remove if unused or pylint will complain
+import math
 from time import sleep
 import adafruit_bus_device.i2c_device as i2c_device
 from adafruit_register.i2c_struct import UnaryStruct, ROUnaryStruct
@@ -234,6 +235,8 @@ def __init__(self, i2c_bus, address=_DPS310_DEFAULT_ADDRESS):
             1040384,
             2088960,
         )
+        self.sea_level_pressure = 1013.25
+        """Pressure in hectoPascals at sea level. Used to calibrate `altitude`."""
         self.initialize()
 
     def initialize(self):
@@ -301,6 +304,12 @@ def pressure(self):
         final_pressure = pres_calc / 100
         return final_pressure
 
+    @property
+    def altitude(self):
+        """The altitude based on the sea level pressure (`sea_level_pressure`) - which you must
+           enter ahead of time)"""
+        return 44330 * (1.0 - math.pow(self.pressure / self.sea_level_pressure, 0.1903))
+
     @property
     def temperature(self):
         """The current temperature reading in degrees C"""