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Adafruit_CircuitPython_HTS221/adafruit_hts221.py
siddacious 42767474d2 humidity correction working
2020-02-21 14:16:34 -08:00

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# The MIT License (MIT)
#
# Copyright (c) 2020 Bryan Siepert for Adafruit Industries
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
"""
`adafruit_hts221`
================================================================================
Helper library for the HTS221 Humidity and Temperature Sensor
* Author(s): Bryan Siepert
Implementation Notes
--------------------
**Hardware:**
* `HTS221 Breakout <https://www.adafruit.com/products/4535>`_
**Software and Dependencies:**
* Adafruit CircuitPython firmware for the supported boards:
https://circuitpython.org/downloads
* Adafruit's Bus Device library: https://github.com/adafruit/Adafruit_CircuitPython_BusDevice
* Adafruit's Register library: https://github.com/adafruit/Adafruit_CircuitPython_Register
"""
__version__ = "0.0.0-auto.0"
__repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_HTS221.git"
from micropython import const
import adafruit_bus_device.i2c_device as i2cdevice
from adafruit_register.i2c_struct import ROUnaryStruct
from adafruit_register.i2c_bits import RWBits, ROBits
from adafruit_register.i2c_bit import RWBit
_WHO_AM_I = const(0x0F)
_CTRL_REG1 = const(0x20)
_CTRL_REG2 = const(0x21)
_CTRL_REG3 = const(0x22)
# some addresses are anded to set the top bit so that multi-byte reads will work
_HUMIDITY_OUT_L = const(0x28 | 0x80) # Humidity output register (LSByte)
_TEMP_OUT_L = const(0x2A | 0x80) # Temperature output register (LSByte)
_H0_RH_X2 = const(0x30) # Humididy calibration LSB values
_H1_RH_X2 = const(0x31) # Humididy calibration LSB values
_T0_DEGC_X8 = const(0x32) # First byte of T0, T1 calibration values
_T1_DEGC_X8 = const(0x33) # First byte of T0, T1 calibration values
_T1_T0_MSB = const(0x35) # Top 2 bits of T0 and T1 (each are 10 bits)
_H0_T0_OUT = const(0x36 | 0x80) # Humididy calibration Time 0 value
_H1_T1_OUT = const(0x3A | 0x80) # Humididy calibration Time 1 value
_T0_OUT = const(0x3C | 0x80) # T0_OUT LSByte
_T1_OUT = const(0x3E | 0x80) # T1_OUT LSByte
_HTS221_CHIP_ID = 0xBC
_HTS221_DEFAULT_ADDRESS = 0x5F
class CV:
"""struct helper"""
@classmethod
def add_values(cls, value_tuples):
"creates CV entires"
cls.string = {}
cls.lsb = {}
for value_tuple in value_tuples:
name, value, string, lsb = value_tuple
setattr(cls, name, value)
cls.string[value] = string
cls.lsb[value] = lsb
@classmethod
def is_valid(cls, value):
"Returns true if the given value is a member of the CV"
return value in cls.string
class Rate(CV):
"""Options for ``data_rate``
+-----------------------+------------------------------------------------------------------+
| Rate | Description |
+-----------------------+------------------------------------------------------------------+
| ``Rate.ONE_SHOT`` | Setting `data_rate` to ``Rate.ONE_SHOT`` takes a single humidity |
| | and temperature measurement |
+-----------------------+------------------------------------------------------------------+
| ``Rate.RATE_1_HZ`` | 1 Hz |
+-----------------------+------------------------------------------------------------------+
| ``Rate.RATE_7_HZ`` | 7 Hz |
+-----------------------+------------------------------------------------------------------+
| ``Rate.RATE_12_5_HZ`` | 12.5 Hz |
+-----------------------+------------------------------------------------------------------+
"""
pass # pylint: disable=unnecessary-pass
Rate.add_values(
(
("RATE_ONE_SHOT", 0, 0, None),
("RATE_1_HZ", 1, 1, None),
("RATE_7_HZ", 2, 7, None),
("RATE_12_5_HZ", 3, 12.5, None),
)
)
# def bp(val):
# return format(val, "#010b")
class HTS221: # pylint: disable=too-many-instance-attributes
"""Library for the ST LPS2x family of humidity sensors
:param ~busio.I2C i2c_bus: The I2C bus the HTS221HB is connected to.
:param address: The I2C device address for the sensor. Default is ``0x5d`` but will accept
``0x5c`` when the ``SDO`` pin is connected to Ground.
"""
_chip_id = ROUnaryStruct(_WHO_AM_I, "<B")
_boot = RWBit(_CTRL_REG2, 7)
enabled = RWBit(_CTRL_REG1, 7)
"""Controls the power down state of the sensor. Setting to `False` will shut the sensor down"""
_data_rate = RWBits(2, _CTRL_REG1, 0)
_raw_temperature = ROUnaryStruct(_TEMP_OUT_L, "<h")
_raw_humidity = ROUnaryStruct(_HUMIDITY_OUT_L, "<b")
# humidity calibration consts
_t0_deg_c_x8_lsbyte = ROBits(8, _T0_DEGC_X8, 0)
_t1_deg_c_x8_lsbyte = ROBits(8, _T1_DEGC_X8, 0)
_t1_t0_deg_c_x8_msbits = ROBits(4, _T1_T0_MSB, 0)
_t0_out = ROUnaryStruct(_T0_OUT, "<h")
_t1_out = ROUnaryStruct(_T1_OUT, "<h")
_h0_rh_x2 = ROUnaryStruct(_H0_RH_X2, "<B")
_h1_rh_x2 = ROUnaryStruct(_H1_RH_X2, "<B")
_h0_t0_out = ROUnaryStruct(_H0_T0_OUT, "<h")
_h1_t0_out = ROUnaryStruct(_H1_T1_OUT, "<h")
def __init__(self, i2c_bus, address=_HTS221_DEFAULT_ADDRESS):
self.i2c_device = i2cdevice.I2CDevice(i2c_bus, address)
if not self._chip_id in [_HTS221_CHIP_ID]:
raise RuntimeError(
"Failed to find HTS221HB! Found chip ID 0x%x" % self._chip_id
)
self.boot()
self.enabled = True
self.data_rate = Rate.RATE_12_5_HZ # pylint:disable=no-member
t1_t0_msbs = self._t1_t0_deg_c_x8_msbits
self.t0_deg_c = self._t0_deg_c_x8_lsbyte
self.t0_deg_c |= (t1_t0_msbs & 0b0011) << 8
self.t1_deg_c = self._t1_deg_c_x8_lsbyte
self.t1_deg_c |= (t1_t0_msbs & 0b1100) << 6
self.t0_out = self._t0_out
self.t1_out = self._t1_out
self.h0_rh = self._h0_rh_x2
self.h1_rh = self._h1_rh_x2
self.h0_out = self._h0_t0_out
self.h1_out = self._h1_t0_out
def _correct_humidity(self):
pass
def _correct_temp(self):
pass
def boot(self):
"""Reset the sensor, restoring all configuration registers to their defaults"""
self._boot = True
# wait for the reset to finish
while self._boot:
pass
@property
def humidity(self):
"""The current humidity measurement in hPa"""
hum = ((self.h1_rh) - (self.h0_rh)) / 2.0 # remove x2 multiple
# Calculate humidity in decimal of grade centigrades i.e. 15.0 = 150.
h_temp = ((self._raw_humidity - self.h0_out) * hum) / (
self.h1_out - self.h0_out
)
hum = self.h0_rh / 2.0 # remove x2 multiple
return hum + h_temp # provide signed % measurement unit
@property
def temperature(self):
"""The current temperature measurement in degrees C"""
temp = (self._raw_temperature - self.t0_out) * (self.t1_deg_c - self.t0_deg_c)
temp /= (self.t1_out - self.t0_out) + self.t0_deg_c
return temp
# Calibration LSB delta + Calibration offset?
@property
def data_rate(self):
"""The rate at which the sensor measures ``humidity`` and ``temperature``. ``data_rate``
shouldbe set to one of the values of ``adafruit_lps2x.DataRate``. Note that setting
``data_rate``to ``Rate.ONE_SHOT`` places the sensor into a low-power shutdown mode where
measurements toupdate ``humidity`` and ``temperature`` are only taken when
``take_measurement`` is called."""
return self._data_rate
@data_rate.setter
def data_rate(self, value):
if not Rate.is_valid(value):
raise AttributeError("data_rate must be a `Rate`")
self._data_rate = value
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