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50 lines
1.3 KiB
50 lines
1.3 KiB
2 years ago
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#!/usr/bin/env python
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import time
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from bme280 import BME280
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from subprocess import PIPE, Popen
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try:
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from smbus2 import SMBus
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except ImportError:
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from smbus import SMBus
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print("""compensated-temperature.py - Use the CPU temperature to compensate temperature
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readings from the BME280 sensor. Method adapted from Initial State's Enviro pHAT
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review: https://medium.com/@InitialState/tutorial-review-enviro-phat-for-raspberry-pi-4cd6d8c63441
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Press Ctrl+C to exit!
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""")
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# Initialise the BME280
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bus = SMBus(1)
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bme280 = BME280(i2c_dev=bus)
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# Gets the CPU temperature in degrees C
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def get_cpu_temperature():
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process = Popen(['vcgencmd', 'measure_temp'], stdout=PIPE)
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output, _error = process.communicate()
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output = output.decode()
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return float(output[output.index('=') + 1:output.rindex("'")])
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factor = 0.6 # Smaller numbers adjust temp down, vice versa
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smooth_size = 10 # Dampens jitter due to rapid CPU temp changes
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cpu_temps = []
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while True:
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cpu_temp = get_cpu_temperature()
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cpu_temps.append(cpu_temp)
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if len(cpu_temps) > smooth_size:
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cpu_temps = cpu_temps[1:]
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smoothed_cpu_temp = sum(cpu_temps) / float(len(cpu_temps))
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raw_temp = bme280.get_temperature()
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comp_temp = raw_temp - ((smoothed_cpu_temp - raw_temp) / factor)
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print("Compensated temperature: {:05.2f} *C".format(comp_temp))
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time.sleep(1.0)
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