-
Notifications
You must be signed in to change notification settings - Fork 25
/
__init__.py
279 lines (234 loc) · 10.6 KB
/
__init__.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
"""BME280 Driver."""
from i2cdevice import Device, Register, BitField, _int_to_bytes
from i2cdevice.adapter import LookupAdapter, Adapter
import struct
import time
__version__ = '0.1.1'
CHIP_ID = 0x60
I2C_ADDRESS_GND = 0x76
I2C_ADDRESS_VCC = 0x77
class S8Adapter(Adapter):
"""Convert unsigned 8bit integer to signed."""
def _decode(self, value):
if value & (1 << 7):
value -= 1 << 8
return value
class S16Adapter(Adapter):
"""Convert unsigned 16bit integer to signed."""
def _decode(self, value):
return struct.unpack('<h', _int_to_bytes(value, 2))[0]
class U16Adapter(Adapter):
"""Convert from bytes to an unsigned 16bit integer."""
def _decode(self, value):
return struct.unpack('<H', _int_to_bytes(value, 2))[0]
class H5Adapter(S16Adapter):
def _decode(self, value):
b = _int_to_bytes(value, 2)
r = ((b[0] >> 4) & 0x0F) | (b[1] << 4)
if r & (1 << 11):
r = r - 1 << 12
return r
class H4Adapter(S16Adapter):
def _decode(self, value):
b = _int_to_bytes(value, 2)
r = (b[0] << 4) | (b[1] & 0x0F)
if r & (1 << 11):
r = r - 1 << 12
return r
class BME280Calibration():
def __init__(self):
self.dig_t1 = 0
self.dig_t2 = 0
self.dig_t3 = 0
self.dig_p1 = 0
self.dig_p2 = 0
self.dig_p3 = 0
self.dig_p4 = 0
self.dig_p5 = 0
self.dig_p6 = 0
self.dig_p7 = 0
self.dig_p8 = 0
self.dig_p9 = 0
self.dig_h1 = 0.0
self.dig_h2 = 0.0
self.dig_h3 = 0.0
self.dig_h4 = 0.0
self.dig_h5 = 0.0
self.dig_h6 = 0.0
self.temperature_fine = 0
def set_from_namedtuple(self, value):
# Iterate through a tuple supplied by i2cdevice
# and copy its values into the class attributes
for key in self.__dict__.keys():
try:
setattr(self, key, getattr(value, key))
except AttributeError:
pass
def compensate_temperature(self, raw_temperature):
var1 = (raw_temperature / 16384.0 - self.dig_t1 / 1024.0) * self.dig_t2
var2 = raw_temperature / 131072.0 - self.dig_t1 / 8192.0
var2 = var2 * var2 * self.dig_t3
self.temperature_fine = (var1 + var2)
return self.temperature_fine / 5120.0
def compensate_pressure(self, raw_pressure):
var1 = self.temperature_fine / 2.0 - 64000.0
var2 = var1 * var1 * self.dig_p6 / 32768.0
var2 = var2 + var1 * self.dig_p5 * 2
var2 = var2 / 4.0 + self.dig_p4 * 65536.0
var1 = (self.dig_p3 * var1 * var1 / 524288.0 + self.dig_p2 * var1) / 524288.0
var1 = (1.0 + var1 / 32768.0) * self.dig_p1
pressure = 1048576.0 - raw_pressure
pressure = (pressure - var2 / 4096.0) * 6250.0 / var1
var1 = self.dig_p9 * pressure * pressure / 2147483648.0
var2 = pressure * self.dig_p8 / 32768.0
return pressure + (var1 + var2 + self.dig_p7) / 16.0
def compensate_humidity(self, raw_humidity):
var1 = self.temperature_fine - 76800.0
var2 = self.dig_h4 * 64.0 + (self.dig_h5 / 16384.0) * var1
var3 = raw_humidity - var2
var4 = self.dig_h2 / 65536.0
var5 = 1.0 + (self.dig_h3 / 67108864.0) * var1
var6 = 1.0 + (self.dig_h6 / 67108864.0) * var1 * var5
var6 = var3 * var4 * (var5 * var6)
humidity = var6 * (1.0 - self.dig_h1 * var6 / 524288.0)
return max(0.0, min(100.0, humidity))
class BME280:
def __init__(self, i2c_addr=I2C_ADDRESS_GND, i2c_dev=None):
self.calibration = BME280Calibration()
self._is_setup = False
self._i2c_addr = i2c_addr
self._i2c_dev = i2c_dev
self._bme280 = Device([I2C_ADDRESS_GND, I2C_ADDRESS_VCC], i2c_dev=self._i2c_dev, bit_width=8, registers=(
Register('CHIP_ID', 0xD0, fields=(
BitField('id', 0xFF),
)),
Register('RESET', 0xE0, fields=(
BitField('reset', 0xFF),
)),
Register('STATUS', 0xF3, fields=(
BitField('measuring', 0b00001000), # 1 when conversion is running
BitField('im_update', 0b00000001), # 1 when NVM data is being copied
)),
Register('CTRL_MEAS', 0xF4, fields=(
BitField('osrs_t', 0b11100000, # Temperature oversampling
adapter=LookupAdapter({
1: 0b001,
2: 0b010,
4: 0b011,
8: 0b100,
16: 0b101
})),
BitField('osrs_p', 0b00011100, # Pressure oversampling
adapter=LookupAdapter({
1: 0b001,
2: 0b010,
4: 0b011,
8: 0b100,
16: 0b101})),
BitField('mode', 0b00000011, # Power mode
adapter=LookupAdapter({
'sleep': 0b00,
'forced': 0b10,
'normal': 0b11})),
)),
Register('CTRL_HUM', 0xF2, fields=(
BitField('osrs_h', 0b00000111, # Humidity oversampling
adapter=LookupAdapter({
1: 0b001,
2: 0b010,
4: 0b011,
8: 0b100,
16: 0b101})),
)),
Register('CONFIG', 0xF5, fields=(
BitField('t_sb', 0b11100000, # Temp standby duration in normal mode
adapter=LookupAdapter({
0.5: 0b000,
62.5: 0b001,
125: 0b010,
250: 0b011,
500: 0b100,
1000: 0b101,
10: 0b110,
20: 0b111})),
BitField('filter', 0b00011100), # Controls the time constant of the IIR filter
BitField('spi3w_en', 0b0000001, read_only=True), # Enable 3-wire SPI interface when set to 1. IE: Don't set this bit!
)),
Register('DATA', 0xF7, fields=(
BitField('humidity', 0x000000000000FFFF),
BitField('temperature', 0x000000FFFFF00000),
BitField('pressure', 0xFFFFF00000000000)
), bit_width=8 * 8),
Register('CALIBRATION', 0x88, fields=(
BitField('dig_t1', 0xFFFF << 16 * 12, adapter=U16Adapter()), # 0x88 0x89
BitField('dig_t2', 0xFFFF << 16 * 11, adapter=S16Adapter()), # 0x8A 0x8B
BitField('dig_t3', 0xFFFF << 16 * 10, adapter=S16Adapter()), # 0x8C 0x8D
BitField('dig_p1', 0xFFFF << 16 * 9, adapter=U16Adapter()), # 0x8E 0x8F
BitField('dig_p2', 0xFFFF << 16 * 8, adapter=S16Adapter()), # 0x90 0x91
BitField('dig_p3', 0xFFFF << 16 * 7, adapter=S16Adapter()), # 0x92 0x93
BitField('dig_p4', 0xFFFF << 16 * 6, adapter=S16Adapter()), # 0x94 0x95
BitField('dig_p5', 0xFFFF << 16 * 5, adapter=S16Adapter()), # 0x96 0x97
BitField('dig_p6', 0xFFFF << 16 * 4, adapter=S16Adapter()), # 0x98 0x99
BitField('dig_p7', 0xFFFF << 16 * 3, adapter=S16Adapter()), # 0x9A 0x9B
BitField('dig_p8', 0xFFFF << 16 * 2, adapter=S16Adapter()), # 0x9C 0x9D
BitField('dig_p9', 0xFFFF << 16 * 1, adapter=S16Adapter()), # 0x9E 0x9F
BitField('dig_h1', 0x00FF), # 0xA1 uint8
), bit_width=26 * 8),
Register('CALIBRATION2', 0xE1, fields=(
BitField('dig_h2', 0xFFFF0000000000, adapter=S16Adapter()), # 0xE1 0xE2
BitField('dig_h3', 0x0000FF00000000), # 0xE3 uint8
BitField('dig_h4', 0x000000FFFF0000, adapter=H4Adapter()), # 0xE4 0xE5[3:0]
BitField('dig_h5', 0x00000000FFFF00, adapter=H5Adapter()), # 0xE5[7:4] 0xE6
BitField('dig_h6', 0x000000000000FF, adapter=S8Adapter()) # 0xE7 int8
), bit_width=7 * 8)
))
def setup(self, mode='normal', temperature_oversampling=16, pressure_oversampling=16, humidity_oversampling=16, temperature_standby=500):
if self._is_setup:
return
self._is_setup = True
self._bme280.select_address(self._i2c_addr)
self._mode = mode
if mode == "forced":
mode = "sleep"
try:
chip = self._bme280.get('CHIP_ID')
if chip.id != CHIP_ID:
raise RuntimeError("Unable to find bme280 on 0x{:02x}, CHIP_ID returned {:02x}".format(self._i2c_addr, chip.id))
except IOError:
raise RuntimeError("Unable to find bme280 on 0x{:02x}, IOError".format(self._i2c_addr))
self._bme280.set('RESET', reset=0xB6)
time.sleep(0.1)
self._bme280.set('CTRL_HUM', osrs_h=humidity_oversampling)
self._bme280.set('CTRL_MEAS',
mode=mode,
osrs_t=temperature_oversampling,
osrs_p=pressure_oversampling)
self._bme280.set('CONFIG',
t_sb=temperature_standby,
filter=2)
self.calibration.set_from_namedtuple(self._bme280.get('CALIBRATION'))
self.calibration.set_from_namedtuple(self._bme280.get('CALIBRATION2'))
def update_sensor(self):
self.setup()
if self._mode == "forced":
self._bme280.set('CTRL_MEAS', mode="forced")
while self._bme280.get('STATUS').measuring:
time.sleep(0.001)
raw = self._bme280.get('DATA')
self.temperature = self.calibration.compensate_temperature(raw.temperature)
self.pressure = self.calibration.compensate_pressure(raw.pressure) / 100.0
self.humidity = self.calibration.compensate_humidity(raw.humidity)
def get_temperature(self):
self.update_sensor()
return self.temperature
def get_pressure(self):
self.update_sensor()
return self.pressure
def get_humidity(self):
self.update_sensor()
return self.humidity
def get_altitude(self, qnh=1013.25):
self.update_sensor()
pressure = self.get_pressure()
altitude = 44330.0 * (1.0 - pow(pressure / qnh, (1.0 / 5.255)))
return altitude