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https://github.com/pimoroni/grow-python
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54 lines
1.4 KiB
Python
54 lines
1.4 KiB
Python
#!/usr/bin/env python3
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import time
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from bme280 import BME280
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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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import logging
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logging.basicConfig(
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format='%(asctime)s.%(msecs)03d %(levelname)-8s %(message)s',
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level=logging.INFO,
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datefmt='%Y-%m-%d %H:%M:%S')
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logging.info("""compensated-temperature.py - Use the CPU temperature
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to compensate temperature readings from the BME280 sensor.
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Method adapted from Initial State's Enviro pHAT review:
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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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bus = SMBus(1)
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bme280 = BME280(i2c_dev=bus)
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# Get the temperature of the CPU for compensation
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def get_cpu_temperature():
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with open("/sys/class/thermal/thermal_zone0/temp", "r") as f:
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temp = f.read()
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temp = int(temp) / 1000.0
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return temp
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# Tuning factor for compensation. Decrease this number to adjust the
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# temperature down, and increase to adjust up
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factor = 2.25
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cpu_temps = [get_cpu_temperature()] * 5
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while True:
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cpu_temp = get_cpu_temperature()
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# Smooth out with some averaging to decrease jitter
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cpu_temps = cpu_temps[1:] + [cpu_temp]
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avg_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 - ((avg_cpu_temp - raw_temp) / factor)
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logging.info("Compensated temperature: {:05.2f} *C".format(comp_temp))
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time.sleep(1.0)
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