58 lines
1.6 KiB
Python
Executable File
58 lines
1.6 KiB
Python
Executable File
#!/usr/bin/env python
|
|
|
|
import time
|
|
import bme680
|
|
from subprocess import PIPE, Popen
|
|
|
|
|
|
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(b'=') + 1:output.rindex(b"'")])
|
|
|
|
|
|
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)
|