AQmon/lua_modules/bme280.lua at master · avaldebe/AQmon · GitHub

History

320 lines (294 loc) · 11.4 KB

Raw

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

280

281

282

283

284

285

286

287

288

289

290

291

292

293

294

295

296

297

298

299

300

301

302

303

304

305

306

307

308

309

310

311

312

313

314

315

316

317

318

319

320

--[[

bme280.lua for ESP8266 with nodemcu-firmware

Read temperature, preassure and relative humidity from BME280 sensors

More info at https://github.com/avaldebe/AQmon

Written by Álvaro Valdebenito,

based on:

- bme280.lua by WG

https://github.com/wogum/esp12

- BME280_driver by BoschSensortec

https://github.com/BoschSensortec/BME280_driver

- bme280.py by Kieran Brownlees

https://github.com/kbrownlees/bme280

- Adafruit_BME280.py by adafruit

https://github.com/adafruit/Adafruit_Python_BME280

- SparkFunBME280.cpp by sparkfun

https://github.com/sparkfun/SparkFun_BME280_Arduino_Library

- Unsigned to signed conversion, eg uint16_t (unsigned short) to int16_t (short)

http://stackoverflow.com/questions/17152300/unsigned-to-signed-without-comparison

Note:

bit.rshift(x,n)~=x/2^n for n<0, use bit.arshift(x,n) instead

MIT license, http://opensource.org/licenses/MIT

]]

local M={

name=..., -- module name, upvalue from require('module-name')

model=nil, -- sensor model: BME280

verbose=nil, -- verbose output

debug=nil, -- additional ckecks

oss=0x01, -- default oversamplig: 0=skip, 1=x1 .. 5=x16

mode=0x03, -- default sampling: 0=sleep, 1&2=forced(on demand), 3:normal(continious)

temperature=nil,-- integer value of temperature [0.01 C]

pressure =nil,-- integer value of preassure [Pa]=[0.01 hPa]

humidity =nil -- integer value of rel.humidity [0.01 %]

}

_G[M.name]=M

-- BME280 has 2 possible addresses

local ADDR = {0x76,0x77}

-- calibration coefficients

local T,P,H={},{},{} -- T1,..,T3,P1,..,P9,H1,..,H6

local function int16_t(uint,nbits)

-- first negative number

-- uint8_t (unsigned char ): 2^7

-- uint16_t(unsigned short): 2^15

-- uint32_t(unsigned long ): 2^31

local first_neg=({[8]=0x80,[16]=0x8000})[nbits or 16]

return uint-bit.band(uint,first_neg)*2

end

-- i2c helper functions

local function i2c_write(addr,...)

local c

i2c.start(0)

c = i2c.address(0,addr,i2c.TRANSMITTER)

if arg.n>0 and c then i2c.write(0,unpack(arg)) end

i2c.stop(0)

return c -- device found?

end

local function i2c_read(addr,reg,nbyte)

local c = i2c_write(addr,reg)

assert(not M.debug or c,

('Failed write REG=0x%02X to device ADDR=0x%02X'):format(reg,addr))

i2c.start(0)

i2c.address(0,addr,i2c.RECEIVER)

c = i2c.read(0,nbyte)

i2c.stop(0)

assert(not M.debug or c:len()==nbyte,

('Failed read REG=0x%02X from device ADDR=0x%02X'):format(reg,addr))

return c

end

-- sampling configuration

local init=false

local function config(...)

-- ensure module is initialized

assert(init,('Need %s.init(...) before %s.config(...)'):format(M.name,M.name))

local REG_COMMAND

-- sampling: normal/continous mode (M.mode:3)

if M.mode==0x03 then

-- Continious sampling setup (if M.mode==0x03), see DS 7.4.6.

-- dt: sample every dt; dt=1000ms (5<<5).

-- IIR: data=(data_new+(IIR-1)*data_old)/IIR; IIR=4 (2<<2).

-- spi3w: enhable 3-wire SPI interface; na (0<<1).

REG_COMMAND=0xA8 -- 5*2^5+2*2^2+0*2^1

--REG_COMMAND=0xA0 -- 5*2^5+0*2^2+0*2^1 IIR disabled

-- REG_CONFIG 0xF5 swriteable only in sleep mode, update only if needed

local c = i2c_read(ADDR,0xF5,1)

if REG_COMMAND~=c:byte() then

i2c_write(ADDR,0xF4, -- REG_CONTROL_MEAS,REG_CONFIG

0x00,REG_COMMAND) -- sleep mode ,config

end

-- oversampling: all modes

local oss_t,oss_h,oss_p=...

-- H oversampling 2^(M.oss_h-1):

i2c_write(ADDR,0xF2, -- REG_CONTROL_HUM

bit.band(oss_h or M.oss,0x07))

-- T oversampling 2^(M.oss_t-1), P oversampling 2^(M.oss_p-1), mode M.mode

i2c_write(ADDR,0xF4, -- REG_CONTROL_MEAS

bit.band(oss_t or M.oss,0x07)*32

+bit.band(oss_p or M.oss,0x07)*4

+bit.band(M.mode,0x03))

-- oversampling delay: forced/on-demmand mode (M.mode:1|2), see DS 11.1

if M.mode==0x01 or M.mode==0x02 then

-- t_meas,max=1.25 [ms]+t_temp,max+t_pres,max+t_rhum,max, where

-- t_temp,max= 2.3*2^oss_t [ms]

-- t_pres,max= 2.3*2^oss_p + 0.575 [ms]

-- t_rhum,max= 2.3*2^oss_h + 0.575 [ms]

-- then, t_meas,max=2.4+2.3*(2^oss_t+2^oss_h+2^oss_p) [ms]

local WAIT=2400+2300*(bit.bit(oss_t or M.oss)

+bit.bit(oss_h or M.oss)

+bit.bit(oss_p or M.oss)) -- 9.3,..,112.8 ms

tmr.delay(WAIT)

end

-- initialize module

function M.init(SDA,SCL,volatile,...)

-- volatile module

if volatile==true then

_G[M.name],package.loaded[M.name]=nil,nil

end

-- init i2c bus

i2c.setup(0,SDA,SCL,i2c.SLOW)

-- M.init suceeded after/when read calibration coeff.

init=(next(T)~=nil)and(next(P)~=nil)and(next(H)~=nil)

if not init then

local found,c

-- verify device address

for c=1,#ADDR do

found=i2c_write(ADDR[c])

if found then

ADDR=ADDR[c]

break

end

if M.verbose==true then

print(found and

('%s: address 0x%02X.'):format(M.name,ADDR) or

('%s: unknown address.'):format(M.name) )

end

-- verify device ID

if found then

c = i2c_read(ADDR,0xD0,1) -- REG_CHIPID

-- CHIPID: BMP085/BMP180 0x55, BMP280 0x58, BME280 0x60

M.model=({[0x55]='BMP180',[0x58]='BMP280',[0x60]='BME280'})[c:byte()]

found=(M.model=='BME280')

end

if M.verbose==true then

print(found and

('%s: model %q.'):format(M.name,M.model) or

('%s: unknown model.'):format(M.name))

end

-- read calibration coeff.

if found then

c = i2c_read(ADDR,0x88,24) -- calib00 0x88 .. calib23 0x9F

..i2c_read(ADDR,0xA1, 1) -- calib25 0xA1

..i2c_read(ADDR,0xE1, 7) -- calib26 0xE1 .. calib32 0xE7

if M.debug==true then

print(('%s:'):format(M.name))

local i

for i=1,24 do

print(('--calib%02d=0x%02X:c:byte(%02d)=0x%02X')

:format(i-1,0x88+i-1,i,c:byte(i)))

end

i=25

print(('--calib%02d=0x%02X:c:byte(%02d)=0x%02X')

:format(i,0xA1,i,c:byte(i)))

for i=26,32 do

print(('--calib%02d=0x%02X:c:byte(%02d)=0x%02X')

:format(i,0xE1+i-26,i,c:byte(i)))

end

-- unpack CALIBRATION: T1,..,T3,P1,..,P9,H1,..,H7

T[1]= c:byte( 1)+c:byte( 2)*256 -- 0x88,0x89; unsigned short

T[2]=int16_t(c:byte( 3)+c:byte( 4)*256) -- 0x8A,0x8B; (signed) short

T[3]=int16_t(c:byte( 5)+c:byte( 6)*256) -- 0x8C,0x8D; (signed) short

P[1]= c:byte( 7)+c:byte( 8)*256 -- 0x8E,0x8F; unsigned short

P[2]=int16_t(c:byte( 9)+c:byte(10)*256) -- 0x90,0x91; (signed) short

P[3]=int16_t(c:byte(11)+c:byte(12)*256) -- 0x92,0x93; (signed) short

P[4]=int16_t(c:byte(13)+c:byte(14)*256) -- 0x94,0x95; (signed) short

P[5]=int16_t(c:byte(15)+c:byte(16)*256) -- 0x96,0x97; (signed) short

P[6]=int16_t(c:byte(17)+c:byte(18)*256) -- 0x98,0x99; (signed) short

P[7]=int16_t(c:byte(19)+c:byte(20)*256) -- 0x9A,0x9B; (signed) short

P[8]=int16_t(c:byte(21)+c:byte(22)*256) -- 0x9C,0x9D; (signed) short

P[9]=int16_t(c:byte(23)+c:byte(24)*256) -- 0x9E,0x9F; (signed) short

H[1]= c:byte(25) -- 0xA1 ; unsigned char

H[2]=int16_t(c:byte(26)+c:byte(27)*256) -- 0xE1,0xE2; (signed) short

H[3]= c:byte(28) -- 0xE3 ; unsigned char

H[4]=bit.band(c:byte(30),0x0F) -- 0xE5[3:0],...

H[4]=int16_t(H[4]+c:byte(29)*16) -- ...,0xE4; (signed) short

H[5]=bit.rshift(c:byte(30),4) -- 0xE5[7:4],...

H[5]=int16_t(H[5]+c:byte(31)*16) -- ...,0xE6; (signed) short

H[6]=int16_t(c:byte(32),8) -- 0xE7 ; (signed) char

c=nil

end

-- M.init suceeded

init=found

end

if init and M.verbose==true then

print(('%s: cal.coeff.'):format(M.name))

print(('--T={%d,%d,%d}.'):format(unpack(T)))

print(('--P={%d,%d,%d,%d,%d,%d,%d,%d,%d}.'):format(unpack(P)))

print(('--H={%d,%d,%d,%d,%d,%d}.'):format(unpack(H)))

end

-- Sampling setup

if init then config(...) end

-- M.init suceeded after/when read calibration coeff.

return init

end

-- read temperature, pressure and relative humidity from BME

-- oss: oversampling setting. 0..5

function M.read(...)

-- ensure module is initialized

assert(init,('Need %s.init(...) before %s.read(...)'):format(M.name,M.name))

-- oversampling: forced/on-demmand mode (M.mode:1|2)

if M.mode==0x01 or M.mode==0x02 then config(...) end

-- RAW DATA

local c = i2c_read(ADDR,0xF7,8) -- REG_PRESSURE_MSB 0xF7 .. REG_HUMIDITY_LSB 0xFE

local p,t,h -- uncompensated

p=c:byte(1)*4096+c:byte(2)*16+c:byte(3)/16 -- pressure

t=c:byte(4)*4096+c:byte(5)*16+c:byte(6)/16 -- temperature

h=c:byte(7)* 256+c:byte(8) -- humidity

c=nil

if M.verbose==true then

print(('%s: UP=%d,UT=%d,UH=%d.'):format(M.name,p,t,h))

end

--[[ Temperature: Adapted from bme280_compensate_temperature_int32.

Calculate actual temperature from uncompensated temperature.

Returns the value in 0.01 degree Centigrade (DegC),

an output value of "5123" equals 51.23 DegC. ]]

local v1,v2,v3,tfine

v1 = t/8 - T[1]*2

v2 = bit.arshift(v1*T[2],11)

v3 = bit.rshift((v1/2)*(v1/2),12)

tfine = v2 + bit.arshift(v3*T[3],14)

t = bit.arshift(tfine*5 + 128,8)

if M.verbose==true then

print(('%s: tfine=%d.'):format(M.name,tfine))

end

--[[ Pressure: Adapted from bme280_compensate_pressure_int32.

Calculate actual pressure from uncompensated pressure.

Returns the value in Pascal (Pa),

and output value of "96386" equals 96386 Pa = 963.86 hPa. ]]

v1 = tfine - 128000

v2 = bit.rshift((v1/8)*(v1/8),12)

v3 = bit.rshift(v2*P[3]/8 + v1*P[2],20) + 32768

v2 = (v2*P[6] + v1*P[5])/4 + bit.lshift(P[4],16)

v1 = bit.rshift(v3*P[1],15)

v3 = nil

if v1==0 then -- p/0 will lua-panic

p = nil

else

p = (1048576 - p - bit.rshift(v2,12))*3125

if p*2>0 then -- avoid overflow (signed) int32

p = p*2/v1

else

p = p/v1*2

end

v1 = bit.rshift((p/8)*(p/8),13)

v1 = bit.arshift(v1*P[9],12)

v2 = bit.arshift(p*P[8],15)

p = p + bit.arshift(v1 + v2 + P[7],4)

end

--[[ Humidity: Adapted from bme280_compensate_humidity_int32.

Calculte actual humidity from uncompensated humidity.

Returns the value in 0.01 %rH.

An output value of "4132.1" represents 41.321 %rH ]]

v1 = tfine - 76800

v2 = bit.rshift(v1*H[6],10)*(bit.rshift(v1*H[3],11) + 32768)

v1 = bit.lshift(h,14) - bit.lshift(H[4],20) - H[5]*v1

v2 = bit.rshift(v2,10) + 2097152

-- Whit this line (based on orig lib) h~=observed rel.hum./2

v1 = bit.rshift(v1 +16384,15)*bit.rshift(v2*H[2] + 8192,14)

-- Hack, gets within 5%rH observed rel.hum.

--v1 = bit.rshift(v1 +16384,15)*bit.rshift(v2*H[2]*2+8192,14)

-- Likely fix, as the orig code dops the last bit of adc_h

--v1 = bit.rshift(v1 + 8192,14)*bit.rshift(v2*H[2] + 8192,14)

v2 = bit.rshift(v1,15)

v2 = bit.rshift(v2*v2,7)

v1 = v1 - bit.rshift(v2*H[1],4)

-- v1 between 0 and 100*2^22

if v1 < 0 then

h = 0 -- 0 %rH

elseif v1 > 0x19000000 then

h = 10000 -- 100 %rH

else

h = bit.rshift(v1,12) -- Q22.10, ie 42313 means 42313/1024=41.321 %rH

h = bit.rshift(h*25,8) -- 0.01 %, ie 4132.1 means 41.321 %rH

end

-- expose results

M.temperature=t -- integer value of temperature [0.01 C]

M.pressure =p -- integer value of preassure [0.01 hPa]

M.humidity =h -- integer value of rel.humidity[0.01 %]

if M.verbose==true then

print(('%s: p=%d[hPa],t=%d[C],h=%d[%%].'):format(M.name,p/100,t/100,h/100))

end

return M

AQmon/lua_modules/bme280.lua at master · avaldebe/AQmon · GitHub

Expand file tree

Breadcrumbs

bme280.lua

Latest commit

History

Breadcrumbs

bme280.lua

File metadata and controls