Merge pull request #24 from pimoroni/examples-tidyup

Tidying up and adding examples

examples/compensated-temperature.py

@@ -0,0 +1,59 @@
+#!/usr/bin/env python
+
+import time
+import bme680
+from subprocess import PIPE, Popen
+
+try:
+    from smbus2 import SMBus
+except ImportError:
+    from smbus import SMBus
+
+print("""compensated-temperature.py - Use the CPU temperature to compensate temperature
+readings from the BME680 sensor. Method adapted from Initial State's Enviro pHAT
+review: https://medium.com/@InitialState/tutorial-review-enviro-phat-for-raspberry-pi-4cd6d8c63441
+
+Press Ctrl+C to exit!
+
+""")
+
+try:
+    sensor = bme680.BME680(bme680.I2C_ADDR_PRIMARY)
+except IOError:
+    sensor = bme680.BME680(bme680.I2C_ADDR_SECONDARY)
+
+# 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)
+
+# Gets the CPU temperature in degrees C
+def get_cpu_temperature():
+    process = Popen(['vcgencmd', 'measure_temp'], stdout=PIPE)
+    output, _error = process.communicate()
+    return float(output[output.index('=') + 1:output.rindex("'")])
+
+factor = 1.0  # Smaller numbers adjust temp down, vice versa
+smooth_size = 10  # Dampens jitter due to rapid CPU temp changes
+
+cpu_temps = []
+
+while True:
+    if sensor.get_sensor_data():
+        cpu_temp = get_cpu_temperature()
+        cpu_temps.append(cpu_temp)
+
+        if len(cpu_temps) > smooth_size:
+            cpu_temps = cpu_temps[1:]
+
+        smoothed_cpu_temp = sum(cpu_temps) / float(len(cpu_temps))
+        raw_temp = sensor.data.temperature
+        comp_temp = raw_temp - ((smoothed_cpu_temp - raw_temp) / factor)
+
+        print("Compensated temperature: {:05.2f} *C".format(comp_temp))
+
+        time.sleep(1.0)

examples/indoor-air-quality.py

@@ -1,14 +1,15 @@
 #!/usr/bin/env python
+
 import bme680
 import time
 
-print("""Estimate indoor air quality
+print("""indoor-air-quality.py - Estimates indoor air quality.
 
 Runs the sensor for a burn-in period, then uses a
 combination of relative humidity and gas resistance
 to estimate indoor air quality as a percentage.
 
-Press Ctrl+C to exit
+Press Ctrl+C to exit!
 
 """)
 

examples/read-all.py

@@ -1,10 +1,11 @@
 #!/usr/bin/env python
+
 import bme680
 import time
 
-print("""Display Temperature, Pressure, Humidity and Gas
+print("""read-all.py - Displays temperature, pressure, humidity, and gas.
 
-Press Ctrl+C to exit
+Press Ctrl+C to exit!
 
 """)
 

examples/temperature-offset.py

@@ -1,7 +1,11 @@
 #!/usr/bin/env python
+
 import bme680
 
-print("""Display Temperature, Pressure and Humidity with different offsets.
+print("""temperature-offset.py - Displays temperature, pressure, and humidity with different offsets.
+
+Press Ctrl+C to exit!
+
 """)
 
 try:
@@ -18,7 +22,6 @@ 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()
@@ -29,7 +32,6 @@ def display_data(offset=0):
     print(output)
     print('')
 
-
 print('Initial readings')
 display_data()
 

examples/temperature-pressure-humidity.py

@@ -1,7 +1,8 @@
 #!/usr/bin/env python
+
 import bme680
 
-print("""Display Temperature, Pressure and Humidity
+print("""temperature-pressure-humidity.py - Displays temperature, pressure, and humidity.
 
 If you don't need gas readings, then you can read temperature,
 pressure and humidity quickly.
@@ -28,12 +29,10 @@ print('Polling:')
 try:
     while True:
         if 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)
 
 except KeyboardInterrupt: