Edutech IoT Team / weather_sense

weather sensor

weather.cpp@0:bd4cdd24731b, 2016-07-01 (annotated)

Committer:
brdarji
Date:
Fri Jul 01 10:35:05 2016 +0000
Revision:
0:bd4cdd24731b
weather sensor;

Who changed what in which revision?

UserRevisionLine numberNew contents of line
brdarji 0:bd4cdd24731b 1 #include "mbed.h"
brdarji 0:bd4cdd24731b 2 #include "BME280.h"
brdarji 0:bd4cdd24731b 3
brdarji 0:bd4cdd24731b 4 BME280::BME280(PinName sda, PinName scl, char slave_adr)
brdarji 0:bd4cdd24731b 5 :
brdarji 0:bd4cdd24731b 6 i2c_p(new I2C(sda, scl)),
brdarji 0:bd4cdd24731b 7 i2c(*i2c_p),
brdarji 0:bd4cdd24731b 8 address(slave_adr),
brdarji 0:bd4cdd24731b 9 t_fine(0)
brdarji 0:bd4cdd24731b 10 {
brdarji 0:bd4cdd24731b 11 initialize();
brdarji 0:bd4cdd24731b 12 }
brdarji 0:bd4cdd24731b 13
brdarji 0:bd4cdd24731b 14 BME280::BME280(I2C &i2c_obj, char slave_adr)
brdarji 0:bd4cdd24731b 15 :
brdarji 0:bd4cdd24731b 16 i2c_p(NULL),
brdarji 0:bd4cdd24731b 17 i2c(i2c_obj),
brdarji 0:bd4cdd24731b 18 address(slave_adr),
brdarji 0:bd4cdd24731b 19 t_fine(0)
brdarji 0:bd4cdd24731b 20 {
brdarji 0:bd4cdd24731b 21 initialize();
brdarji 0:bd4cdd24731b 22 }
brdarji 0:bd4cdd24731b 23
brdarji 0:bd4cdd24731b 24 BME280::~BME280()
brdarji 0:bd4cdd24731b 25 {
brdarji 0:bd4cdd24731b 26 if (NULL != i2c_p)
brdarji 0:bd4cdd24731b 27 delete i2c_p;
brdarji 0:bd4cdd24731b 28 }
brdarji 0:bd4cdd24731b 29
brdarji 0:bd4cdd24731b 30 void BME280::initialize()
brdarji 0:bd4cdd24731b 31 {
brdarji 0:bd4cdd24731b 32 char cmd[18];
brdarji 0:bd4cdd24731b 33
brdarji 0:bd4cdd24731b 34 cmd[0] = 0xf2; // ctrl_hum
brdarji 0:bd4cdd24731b 35 cmd[1] = 0x01; // Humidity oversampling x1
brdarji 0:bd4cdd24731b 36 i2c.write(address, cmd, 2);
brdarji 0:bd4cdd24731b 37
brdarji 0:bd4cdd24731b 38 cmd[0] = 0xf4; // ctrl_meas
brdarji 0:bd4cdd24731b 39 cmd[1] = 0x27; // Temparature oversampling x1, Pressure oversampling x1, Normal mode
brdarji 0:bd4cdd24731b 40 i2c.write(address, cmd, 2);
brdarji 0:bd4cdd24731b 41
brdarji 0:bd4cdd24731b 42 cmd[0] = 0xf5; // config
brdarji 0:bd4cdd24731b 43 cmd[1] = 0xa0; // Standby 1000ms, Filter off
brdarji 0:bd4cdd24731b 44 i2c.write(address, cmd, 2);
brdarji 0:bd4cdd24731b 45
brdarji 0:bd4cdd24731b 46 cmd[0] = 0x88; // read dig_T regs
brdarji 0:bd4cdd24731b 47 i2c.write(address, cmd, 1);
brdarji 0:bd4cdd24731b 48 i2c.read(address, cmd, 6);
brdarji 0:bd4cdd24731b 49
brdarji 0:bd4cdd24731b 50 dig_T1 = (cmd[1] << 8) | cmd[0];
brdarji 0:bd4cdd24731b 51 dig_T2 = (cmd[3] << 8) | cmd[2];
brdarji 0:bd4cdd24731b 52 dig_T3 = (cmd[5] << 8) | cmd[4];
brdarji 0:bd4cdd24731b 53
brdarji 0:bd4cdd24731b 54 DEBUG_PRINT("dig_T = 0x%x, 0x%x, 0x%x\n", dig_T1, dig_T2, dig_T3);
brdarji 0:bd4cdd24731b 55
brdarji 0:bd4cdd24731b 56 cmd[0] = 0x8E; // read dig_P regs
brdarji 0:bd4cdd24731b 57 i2c.write(address, cmd, 1);
brdarji 0:bd4cdd24731b 58 i2c.read(address, cmd, 18);
brdarji 0:bd4cdd24731b 59
brdarji 0:bd4cdd24731b 60 dig_P1 = (cmd[ 1] << 8) | cmd[ 0];
brdarji 0:bd4cdd24731b 61 dig_P2 = (cmd[ 3] << 8) | cmd[ 2];
brdarji 0:bd4cdd24731b 62 dig_P3 = (cmd[ 5] << 8) | cmd[ 4];
brdarji 0:bd4cdd24731b 63 dig_P4 = (cmd[ 7] << 8) | cmd[ 6];
brdarji 0:bd4cdd24731b 64 dig_P5 = (cmd[ 9] << 8) | cmd[ 8];
brdarji 0:bd4cdd24731b 65 dig_P6 = (cmd[11] << 8) | cmd[10];
brdarji 0:bd4cdd24731b 66 dig_P7 = (cmd[13] << 8) | cmd[12];
brdarji 0:bd4cdd24731b 67 dig_P8 = (cmd[15] << 8) | cmd[14];
brdarji 0:bd4cdd24731b 68 dig_P9 = (cmd[17] << 8) | cmd[16];
brdarji 0:bd4cdd24731b 69
brdarji 0:bd4cdd24731b 70 DEBUG_PRINT("dig_P = 0x%x, 0x%x, 0x%x, 0x%x, 0x%x, 0x%x, 0x%x, 0x%x, 0x%x\n", dig_P1, dig_P2, dig_P3, dig_P4, dig_P5, dig_P6, dig_P7, dig_P8, dig_P9);
brdarji 0:bd4cdd24731b 71
brdarji 0:bd4cdd24731b 72 cmd[0] = 0xA1; // read dig_H regs
brdarji 0:bd4cdd24731b 73 i2c.write(address, cmd, 1);
brdarji 0:bd4cdd24731b 74 i2c.read(address, cmd, 1);
brdarji 0:bd4cdd24731b 75 cmd[1] = 0xE1; // read dig_H regs
brdarji 0:bd4cdd24731b 76 i2c.write(address, &cmd[1], 1);
brdarji 0:bd4cdd24731b 77 i2c.read(address, &cmd[1], 7);
brdarji 0:bd4cdd24731b 78
brdarji 0:bd4cdd24731b 79 dig_H1 = cmd[0];
brdarji 0:bd4cdd24731b 80 dig_H2 = (cmd[2] << 8) | cmd[1];
brdarji 0:bd4cdd24731b 81 dig_H3 = cmd[3];
brdarji 0:bd4cdd24731b 82 dig_H4 = (cmd[4] << 4) | (cmd[5] & 0x0f);
brdarji 0:bd4cdd24731b 83 dig_H5 = (cmd[6] << 4) | ((cmd[5]>>4) & 0x0f);
brdarji 0:bd4cdd24731b 84 dig_H6 = cmd[7];
brdarji 0:bd4cdd24731b 85
brdarji 0:bd4cdd24731b 86 DEBUG_PRINT("dig_H = 0x%x, 0x%x, 0x%x, 0x%x, 0x%x, 0x%x\n", dig_H1, dig_H2, dig_H3, dig_H4, dig_H5, dig_H6);
brdarji 0:bd4cdd24731b 87 }
brdarji 0:bd4cdd24731b 88
brdarji 0:bd4cdd24731b 89 float BME280::getTemperature()
brdarji 0:bd4cdd24731b 90 {
brdarji 0:bd4cdd24731b 91 uint32_t temp_raw;
brdarji 0:bd4cdd24731b 92 float tempf;
brdarji 0:bd4cdd24731b 93 char cmd[4];
brdarji 0:bd4cdd24731b 94
brdarji 0:bd4cdd24731b 95 cmd[0] = 0xfa; // temp_msb
brdarji 0:bd4cdd24731b 96 i2c.write(address, cmd, 1);
brdarji 0:bd4cdd24731b 97 i2c.read(address, &cmd[1], 3);
brdarji 0:bd4cdd24731b 98
brdarji 0:bd4cdd24731b 99 temp_raw = (cmd[1] << 12) | (cmd[2] << 4) | (cmd[3] >> 4);
brdarji 0:bd4cdd24731b 100
brdarji 0:bd4cdd24731b 101 int32_t temp;
brdarji 0:bd4cdd24731b 102
brdarji 0:bd4cdd24731b 103 temp =
brdarji 0:bd4cdd24731b 104 (((((temp_raw >> 3) - (dig_T1 << 1))) * dig_T2) >> 11) +
brdarji 0:bd4cdd24731b 105 ((((((temp_raw >> 4) - dig_T1) * ((temp_raw >> 4) - dig_T1)) >> 12) * dig_T3) >> 14);
brdarji 0:bd4cdd24731b 106
brdarji 0:bd4cdd24731b 107 t_fine = temp;
brdarji 0:bd4cdd24731b 108 temp = (temp * 5 + 128) >> 8;
brdarji 0:bd4cdd24731b 109 tempf = (float)temp;
brdarji 0:bd4cdd24731b 110
brdarji 0:bd4cdd24731b 111 return (tempf/100.0f);
brdarji 0:bd4cdd24731b 112 }
brdarji 0:bd4cdd24731b 113
brdarji 0:bd4cdd24731b 114 float BME280::getPressure()
brdarji 0:bd4cdd24731b 115 {
brdarji 0:bd4cdd24731b 116 uint32_t press_raw;
brdarji 0:bd4cdd24731b 117 float pressf;
brdarji 0:bd4cdd24731b 118 char cmd[4];
brdarji 0:bd4cdd24731b 119
brdarji 0:bd4cdd24731b 120 cmd[0] = 0xf7; // press_msb
brdarji 0:bd4cdd24731b 121 i2c.write(address, cmd, 1);
brdarji 0:bd4cdd24731b 122 i2c.read(address, &cmd[1], 3);
brdarji 0:bd4cdd24731b 123
brdarji 0:bd4cdd24731b 124 press_raw = (cmd[1] << 12) | (cmd[2] << 4) | (cmd[3] >> 4);
brdarji 0:bd4cdd24731b 125
brdarji 0:bd4cdd24731b 126 int32_t var1, var2;
brdarji 0:bd4cdd24731b 127 uint32_t press;
brdarji 0:bd4cdd24731b 128
brdarji 0:bd4cdd24731b 129 var1 = (t_fine >> 1) - 64000;
brdarji 0:bd4cdd24731b 130 var2 = (((var1 >> 2) * (var1 >> 2)) >> 11) * dig_P6;
brdarji 0:bd4cdd24731b 131 var2 = var2 + ((var1 * dig_P5) << 1);
brdarji 0:bd4cdd24731b 132 var2 = (var2 >> 2) + (dig_P4 << 16);
brdarji 0:bd4cdd24731b 133 var1 = (((dig_P3 * (((var1 >> 2)*(var1 >> 2)) >> 13)) >> 3) + ((dig_P2 * var1) >> 1)) >> 18;
brdarji 0:bd4cdd24731b 134 var1 = ((32768 + var1) * dig_P1) >> 15;
brdarji 0:bd4cdd24731b 135 if (var1 == 0) {
brdarji 0:bd4cdd24731b 136 return 0;
brdarji 0:bd4cdd24731b 137 }
brdarji 0:bd4cdd24731b 138 press = (((1048576 - press_raw) - (var2 >> 12))) * 3125;
brdarji 0:bd4cdd24731b 139 if(press < 0x80000000) {
brdarji 0:bd4cdd24731b 140 press = (press << 1) / var1;
brdarji 0:bd4cdd24731b 141 } else {
brdarji 0:bd4cdd24731b 142 press = (press / var1) * 2;
brdarji 0:bd4cdd24731b 143 }
brdarji 0:bd4cdd24731b 144 var1 = ((int32_t)dig_P9 * ((int32_t)(((press >> 3) * (press >> 3)) >> 13))) >> 12;
brdarji 0:bd4cdd24731b 145 var2 = (((int32_t)(press >> 2)) * (int32_t)dig_P8) >> 13;
brdarji 0:bd4cdd24731b 146 press = (press + ((var1 + var2 + dig_P7) >> 4));
brdarji 0:bd4cdd24731b 147
brdarji 0:bd4cdd24731b 148 pressf = (float)press;
brdarji 0:bd4cdd24731b 149 return (pressf/100.0f);
brdarji 0:bd4cdd24731b 150 }
brdarji 0:bd4cdd24731b 151
brdarji 0:bd4cdd24731b 152 float BME280::getHumidity()
brdarji 0:bd4cdd24731b 153 {
brdarji 0:bd4cdd24731b 154 uint32_t hum_raw;
brdarji 0:bd4cdd24731b 155 float humf;
brdarji 0:bd4cdd24731b 156 char cmd[4];
brdarji 0:bd4cdd24731b 157
brdarji 0:bd4cdd24731b 158 cmd[0] = 0xfd; // hum_msb
brdarji 0:bd4cdd24731b 159 i2c.write(address, cmd, 1);
brdarji 0:bd4cdd24731b 160 i2c.read(address, &cmd[1], 2);
brdarji 0:bd4cdd24731b 161
brdarji 0:bd4cdd24731b 162 hum_raw = (cmd[1] << 8) | cmd[2];
brdarji 0:bd4cdd24731b 163
brdarji 0:bd4cdd24731b 164 int32_t v_x1;
brdarji 0:bd4cdd24731b 165
brdarji 0:bd4cdd24731b 166 v_x1 = t_fine - 76800;
brdarji 0:bd4cdd24731b 167 v_x1 = (((((hum_raw << 14) -(((int32_t)dig_H4) << 20) - (((int32_t)dig_H5) * v_x1)) +
brdarji 0:bd4cdd24731b 168 ((int32_t)16384)) >> 15) * (((((((v_x1 * (int32_t)dig_H6) >> 10) *
brdarji 0:bd4cdd24731b 169 (((v_x1 * ((int32_t)dig_H3)) >> 11) + 32768)) >> 10) + 2097152) *
brdarji 0:bd4cdd24731b 170 (int32_t)dig_H2 + 8192) >> 14));
brdarji 0:bd4cdd24731b 171 v_x1 = (v_x1 - (((((v_x1 >> 15) * (v_x1 >> 15)) >> 7) * (int32_t)dig_H1) >> 4));
brdarji 0:bd4cdd24731b 172 v_x1 = (v_x1 < 0 ? 0 : v_x1);
brdarji 0:bd4cdd24731b 173 v_x1 = (v_x1 > 419430400 ? 419430400 : v_x1);
brdarji 0:bd4cdd24731b 174
brdarji 0:bd4cdd24731b 175 humf = (float)(v_x1 >> 12);
brdarji 0:bd4cdd24731b 176
brdarji 0:bd4cdd24731b 177 return (humf/1024.0f);
brdarji 0:bd4cdd24731b 178 }