38 lines
1.1 KiB
Python
38 lines
1.1 KiB
Python
from struct import unpack as unp
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from time import sleep_ms
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# SHT20 default address
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SHT20_I2CADDR = 64
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TRI_T_MEASURE_NO_HOLD = b'\xf3'
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TRI_RH_MEASURE_NO_HOLD = b'\xf5'
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READ_USER_REG = b'\xe7'
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WRITE_USER_REG = b'\xe6'
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SOFT_RESET = b'\xfe'
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class SHT20(object):
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def __init__(self, i2c_bus):
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self._address = SHT20_I2CADDR
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self._bus = i2c_bus
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def get_SHT_temperature(self):
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self._bus.writeto(self._address, TRI_T_MEASURE_NO_HOLD)
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sleep_ms(150)
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origin_data = self._bus.readfrom(self._address, 2)
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origin_value = unp('>h', origin_data)[0]
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value = -46.85 + 175.72 * (origin_value / 65536)
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return value
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def get_SHT_relative_humidity(self):
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self._bus.writeto(self._address, TRI_RH_MEASURE_NO_HOLD)
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sleep_ms(150)
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origin_data = self._bus.readfrom(self._address, 2)
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origin_value = unp('>H', origin_data)[0]
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value = -6 + 125 * (origin_value / 65536)
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return value
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def humidity(self):
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return self.get_SHT_relative_humidity()
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def temperature(self):
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return self.get_SHT_temperature()
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