Leon Wehmeier / Mbed OS fiasco_max32630

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Dependencies:   SoftSerial MAX14690 Buffer

Fork of rtos_threading_with_callback by mbed_example

DHT/DHT.cpp@2:bf699e054b34, 2018-02-25 (annotated)

Committer:
lwehmeier
Date:
Sun Feb 25 16:40:28 2018 +0000
Revision:
2:bf699e054b34
changed to modular design; rtos support; BMI160, BMP180, SSD1306, MPU6050, DHT11, SD support implemented; bit stuffing for link layer implemented; priority queue for data transmission; high-priority SPI link layer output thread

Who changed what in which revision?

UserRevisionLine numberNew contents of line
lwehmeier 2:bf699e054b34 1 /*
lwehmeier 2:bf699e054b34 2 * DHT Library for Digital-output Humidity and Temperature sensors
lwehmeier 2:bf699e054b34 3 *
lwehmeier 2:bf699e054b34 4 * Works with DHT11, DHT22
lwehmeier 2:bf699e054b34 5 * SEN11301P, Grove - Temperature&Humidity Sensor (Seeed Studio)
lwehmeier 2:bf699e054b34 6 * SEN51035P, Grove - Temperature&Humidity Sensor Pro (Seeed Studio)
lwehmeier 2:bf699e054b34 7 * AM2302 , temperature-humidity sensor
lwehmeier 2:bf699e054b34 8 * HM2303 , Digital-output humidity and temperature sensor
lwehmeier 2:bf699e054b34 9 *
lwehmeier 2:bf699e054b34 10 * Copyright (C) Wim De Roeve
lwehmeier 2:bf699e054b34 11 * based on DHT22 sensor library by HO WING KIT
lwehmeier 2:bf699e054b34 12 * Arduino DHT11 library
lwehmeier 2:bf699e054b34 13 *
lwehmeier 2:bf699e054b34 14 * Permission is hereby granted, free of charge, to any person obtaining a copy
lwehmeier 2:bf699e054b34 15 * of this software and associated documnetation files (the "Software"), to deal
lwehmeier 2:bf699e054b34 16 * in the Software without restriction, including without limitation the rights
lwehmeier 2:bf699e054b34 17 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
lwehmeier 2:bf699e054b34 18 * copies of the Software, and to permit persons to whom the Software is
lwehmeier 2:bf699e054b34 19 * furished to do so, subject to the following conditions:
lwehmeier 2:bf699e054b34 20 *
lwehmeier 2:bf699e054b34 21 * The above copyright notice and this permission notice shall be included in
lwehmeier 2:bf699e054b34 22 * all copies or substantial portions of the Software.
lwehmeier 2:bf699e054b34 23 *
lwehmeier 2:bf699e054b34 24 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
lwehmeier 2:bf699e054b34 25 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
lwehmeier 2:bf699e054b34 26 * FITNESS OR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
lwehmeier 2:bf699e054b34 27 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
lwehmeier 2:bf699e054b34 28 * LIABILITY WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
lwehmeier 2:bf699e054b34 29 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
lwehmeier 2:bf699e054b34 30 * THE SOFTWARE.
lwehmeier 2:bf699e054b34 31 */
lwehmeier 2:bf699e054b34 32
lwehmeier 2:bf699e054b34 33 #include "DHT.h"
lwehmeier 2:bf699e054b34 34
lwehmeier 2:bf699e054b34 35 #define DHT_DATA_BIT_COUNT 41
lwehmeier 2:bf699e054b34 36
lwehmeier 2:bf699e054b34 37 DHT::DHT(PinName pin,int DHTtype) {
lwehmeier 2:bf699e054b34 38 _pin = pin;
lwehmeier 2:bf699e054b34 39 _DHTtype = DHTtype;
lwehmeier 2:bf699e054b34 40 _firsttime=true;
lwehmeier 2:bf699e054b34 41 }
lwehmeier 2:bf699e054b34 42
lwehmeier 2:bf699e054b34 43 DHT::~DHT() {
lwehmeier 2:bf699e054b34 44 }
lwehmeier 2:bf699e054b34 45
lwehmeier 2:bf699e054b34 46 int DHT::readData() {
lwehmeier 2:bf699e054b34 47 int i, j, retryCount,b;
lwehmeier 2:bf699e054b34 48 unsigned int bitTimes[DHT_DATA_BIT_COUNT];
lwehmeier 2:bf699e054b34 49
lwehmeier 2:bf699e054b34 50 eError err = ERROR_NONE;
lwehmeier 2:bf699e054b34 51 time_t currentTime = time(NULL);
lwehmeier 2:bf699e054b34 52
lwehmeier 2:bf699e054b34 53 DigitalInOut DHT_io(_pin);
lwehmeier 2:bf699e054b34 54
lwehmeier 2:bf699e054b34 55 for (i = 0; i < DHT_DATA_BIT_COUNT; i++) {
lwehmeier 2:bf699e054b34 56 bitTimes[i] = 0;
lwehmeier 2:bf699e054b34 57 }
lwehmeier 2:bf699e054b34 58
lwehmeier 2:bf699e054b34 59 if (!_firsttime) {
lwehmeier 2:bf699e054b34 60 if (int(currentTime - _lastReadTime) < 2) {
lwehmeier 2:bf699e054b34 61 err = ERROR_NO_PATIENCE;
lwehmeier 2:bf699e054b34 62 return err;
lwehmeier 2:bf699e054b34 63 }
lwehmeier 2:bf699e054b34 64 } else {
lwehmeier 2:bf699e054b34 65 _firsttime=false;
lwehmeier 2:bf699e054b34 66 _lastReadTime=currentTime;
lwehmeier 2:bf699e054b34 67 }
lwehmeier 2:bf699e054b34 68 retryCount = 0;
lwehmeier 2:bf699e054b34 69
lwehmeier 2:bf699e054b34 70 do {
lwehmeier 2:bf699e054b34 71 if (retryCount > 125) {
lwehmeier 2:bf699e054b34 72 err = BUS_BUSY;
lwehmeier 2:bf699e054b34 73 return err;
lwehmeier 2:bf699e054b34 74 }
lwehmeier 2:bf699e054b34 75 retryCount ++;
lwehmeier 2:bf699e054b34 76 wait_us(2);
lwehmeier 2:bf699e054b34 77 } while ((DHT_io==0));
lwehmeier 2:bf699e054b34 78
lwehmeier 2:bf699e054b34 79
lwehmeier 2:bf699e054b34 80 DHT_io.output();
lwehmeier 2:bf699e054b34 81 DHT_io = 0;
lwehmeier 2:bf699e054b34 82 wait_ms(18);
lwehmeier 2:bf699e054b34 83 DHT_io = 1;
lwehmeier 2:bf699e054b34 84 wait_us(40);
lwehmeier 2:bf699e054b34 85 DHT_io.input();
lwehmeier 2:bf699e054b34 86
lwehmeier 2:bf699e054b34 87 retryCount = 0;
lwehmeier 2:bf699e054b34 88 do {
lwehmeier 2:bf699e054b34 89 if (retryCount > 40) {
lwehmeier 2:bf699e054b34 90 err = ERROR_NOT_PRESENT;
lwehmeier 2:bf699e054b34 91 return err;
lwehmeier 2:bf699e054b34 92 }
lwehmeier 2:bf699e054b34 93 retryCount++;
lwehmeier 2:bf699e054b34 94 wait_us(1);
lwehmeier 2:bf699e054b34 95 } while ((DHT_io==1));
lwehmeier 2:bf699e054b34 96
lwehmeier 2:bf699e054b34 97 if (err != ERROR_NONE) {
lwehmeier 2:bf699e054b34 98 return err;
lwehmeier 2:bf699e054b34 99 }
lwehmeier 2:bf699e054b34 100
lwehmeier 2:bf699e054b34 101 wait_us(80);
lwehmeier 2:bf699e054b34 102
lwehmeier 2:bf699e054b34 103 for (i = 0; i < 5; i++) {
lwehmeier 2:bf699e054b34 104 for (j = 0; j < 8; j++) {
lwehmeier 2:bf699e054b34 105
lwehmeier 2:bf699e054b34 106 retryCount = 0;
lwehmeier 2:bf699e054b34 107 do {
lwehmeier 2:bf699e054b34 108 if (retryCount > 75) {
lwehmeier 2:bf699e054b34 109 err = ERROR_DATA_TIMEOUT;
lwehmeier 2:bf699e054b34 110 return err;
lwehmeier 2:bf699e054b34 111 }
lwehmeier 2:bf699e054b34 112 retryCount++;
lwehmeier 2:bf699e054b34 113 wait_us(1);
lwehmeier 2:bf699e054b34 114 } while (DHT_io == 0);
lwehmeier 2:bf699e054b34 115 wait_us(40);
lwehmeier 2:bf699e054b34 116 bitTimes[i*8+j]=DHT_io;
lwehmeier 2:bf699e054b34 117
lwehmeier 2:bf699e054b34 118 int count = 0;
lwehmeier 2:bf699e054b34 119 while (DHT_io == 1 && count < 100) {
lwehmeier 2:bf699e054b34 120 wait_us(1);
lwehmeier 2:bf699e054b34 121 count++;
lwehmeier 2:bf699e054b34 122 }
lwehmeier 2:bf699e054b34 123 }
lwehmeier 2:bf699e054b34 124 }
lwehmeier 2:bf699e054b34 125 DHT_io.output();
lwehmeier 2:bf699e054b34 126 DHT_io = 1;
lwehmeier 2:bf699e054b34 127 for (i = 0; i < 5; i++) {
lwehmeier 2:bf699e054b34 128 b=0;
lwehmeier 2:bf699e054b34 129 for (j=0; j<8; j++) {
lwehmeier 2:bf699e054b34 130 if (bitTimes[i*8+j+1] > 0) {
lwehmeier 2:bf699e054b34 131 b |= ( 1 << (7-j));
lwehmeier 2:bf699e054b34 132 }
lwehmeier 2:bf699e054b34 133 }
lwehmeier 2:bf699e054b34 134 DHT_data[i]=b;
lwehmeier 2:bf699e054b34 135 }
lwehmeier 2:bf699e054b34 136
lwehmeier 2:bf699e054b34 137 if (DHT_data[4] == ((DHT_data[0] + DHT_data[1] + DHT_data[2] + DHT_data[3]) & 0xFF)) {
lwehmeier 2:bf699e054b34 138 _lastReadTime = currentTime;
lwehmeier 2:bf699e054b34 139 _lastTemperature=CalcTemperature();
lwehmeier 2:bf699e054b34 140 _lastHumidity=CalcHumidity();
lwehmeier 2:bf699e054b34 141
lwehmeier 2:bf699e054b34 142 } else {
lwehmeier 2:bf699e054b34 143 err = ERROR_CHECKSUM;
lwehmeier 2:bf699e054b34 144 }
lwehmeier 2:bf699e054b34 145
lwehmeier 2:bf699e054b34 146 return err;
lwehmeier 2:bf699e054b34 147
lwehmeier 2:bf699e054b34 148 }
lwehmeier 2:bf699e054b34 149
lwehmeier 2:bf699e054b34 150 float DHT::CalcTemperature() {
lwehmeier 2:bf699e054b34 151 int v;
lwehmeier 2:bf699e054b34 152
lwehmeier 2:bf699e054b34 153 switch (_DHTtype) {
lwehmeier 2:bf699e054b34 154 case DHT11:
lwehmeier 2:bf699e054b34 155 v = DHT_data[2];
lwehmeier 2:bf699e054b34 156 return float(v);
lwehmeier 2:bf699e054b34 157 case DHT22:
lwehmeier 2:bf699e054b34 158 v = DHT_data[2] & 0x7F;
lwehmeier 2:bf699e054b34 159 v *= 256;
lwehmeier 2:bf699e054b34 160 v += DHT_data[3];
lwehmeier 2:bf699e054b34 161 v /= 10;
lwehmeier 2:bf699e054b34 162 if (DHT_data[2] & 0x80)
lwehmeier 2:bf699e054b34 163 v *= -1;
lwehmeier 2:bf699e054b34 164 return float(v);
lwehmeier 2:bf699e054b34 165 }
lwehmeier 2:bf699e054b34 166 return 0;
lwehmeier 2:bf699e054b34 167 }
lwehmeier 2:bf699e054b34 168
lwehmeier 2:bf699e054b34 169 float DHT::ReadHumidity() {
lwehmeier 2:bf699e054b34 170 return _lastHumidity;
lwehmeier 2:bf699e054b34 171 }
lwehmeier 2:bf699e054b34 172
lwehmeier 2:bf699e054b34 173 float DHT::ConvertCelciustoFarenheit(float celsius) {
lwehmeier 2:bf699e054b34 174 return celsius * 9 / 5 + 32;
lwehmeier 2:bf699e054b34 175 }
lwehmeier 2:bf699e054b34 176
lwehmeier 2:bf699e054b34 177 float DHT::ConvertCelciustoKelvin(float celsius) {
lwehmeier 2:bf699e054b34 178 return celsius + 273.15;
lwehmeier 2:bf699e054b34 179 }
lwehmeier 2:bf699e054b34 180
lwehmeier 2:bf699e054b34 181 // dewPoint function NOAA
lwehmeier 2:bf699e054b34 182 // reference: http://wahiduddin.net/calc/density_algorithms.htm
lwehmeier 2:bf699e054b34 183 float DHT::CalcdewPoint(float celsius, float humidity) {
lwehmeier 2:bf699e054b34 184 float A0= 373.15/(273.15 + celsius);
lwehmeier 2:bf699e054b34 185 float SUM = -7.90298 * (A0-1);
lwehmeier 2:bf699e054b34 186 SUM += 5.02808 * log10(A0);
lwehmeier 2:bf699e054b34 187 SUM += -1.3816e-7 * (pow(10, (11.344*(1-1/A0)))-1) ;
lwehmeier 2:bf699e054b34 188 SUM += 8.1328e-3 * (pow(10,(-3.49149*(A0-1)))-1) ;
lwehmeier 2:bf699e054b34 189 SUM += log10(1013.246);
lwehmeier 2:bf699e054b34 190 float VP = pow(10, SUM-3) * humidity;
lwehmeier 2:bf699e054b34 191 float T = log(VP/0.61078); // temp var
lwehmeier 2:bf699e054b34 192 return (241.88 * T) / (17.558-T);
lwehmeier 2:bf699e054b34 193 }
lwehmeier 2:bf699e054b34 194
lwehmeier 2:bf699e054b34 195 // delta max = 0.6544 wrt dewPoint()
lwehmeier 2:bf699e054b34 196 // 5x faster than dewPoint()
lwehmeier 2:bf699e054b34 197 // reference: http://en.wikipedia.org/wiki/Dew_point
lwehmeier 2:bf699e054b34 198 float DHT::CalcdewPointFast(float celsius, float humidity)
lwehmeier 2:bf699e054b34 199 {
lwehmeier 2:bf699e054b34 200 float a = 17.271;
lwehmeier 2:bf699e054b34 201 float b = 237.7;
lwehmeier 2:bf699e054b34 202 float temp = (a * celsius) / (b + celsius) + log(humidity/100);
lwehmeier 2:bf699e054b34 203 float Td = (b * temp) / (a - temp);
lwehmeier 2:bf699e054b34 204 return Td;
lwehmeier 2:bf699e054b34 205 }
lwehmeier 2:bf699e054b34 206
lwehmeier 2:bf699e054b34 207 float DHT::ReadTemperature(eScale Scale) {
lwehmeier 2:bf699e054b34 208 if (Scale == FARENHEIT)
lwehmeier 2:bf699e054b34 209 return ConvertCelciustoFarenheit(_lastTemperature);
lwehmeier 2:bf699e054b34 210 else if (Scale == KELVIN)
lwehmeier 2:bf699e054b34 211 return ConvertCelciustoKelvin(_lastTemperature);
lwehmeier 2:bf699e054b34 212 else
lwehmeier 2:bf699e054b34 213 return _lastTemperature;
lwehmeier 2:bf699e054b34 214 }
lwehmeier 2:bf699e054b34 215
lwehmeier 2:bf699e054b34 216 float DHT::CalcHumidity() {
lwehmeier 2:bf699e054b34 217 int v;
lwehmeier 2:bf699e054b34 218
lwehmeier 2:bf699e054b34 219 switch (_DHTtype) {
lwehmeier 2:bf699e054b34 220 case DHT11:
lwehmeier 2:bf699e054b34 221 v = DHT_data[0];
lwehmeier 2:bf699e054b34 222 return float(v);
lwehmeier 2:bf699e054b34 223 case DHT22:
lwehmeier 2:bf699e054b34 224 v = DHT_data[0];
lwehmeier 2:bf699e054b34 225 v *= 256;
lwehmeier 2:bf699e054b34 226 v += DHT_data[1];
lwehmeier 2:bf699e054b34 227 v /= 10;
lwehmeier 2:bf699e054b34 228 return float(v);
lwehmeier 2:bf699e054b34 229 }
lwehmeier 2:bf699e054b34 230 return 0;
lwehmeier 2:bf699e054b34 231 }
lwehmeier 2:bf699e054b34 232
lwehmeier 2:bf699e054b34 233