FRANCISCO LOZADA / PROYECTOFINAL_FLOZADA

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DHT.cpp@6:b3ec6bbb9565, 2020-02-15 (annotated)

Committer:
flozada
Date:
Sat Feb 15 16:40:35 2020 +0000
Revision:
6:b3ec6bbb9565
Parent:
5:cce2105f7365 
TUTOTRIA FINAL_ SISTEMA DE SENSADO DE TEMPERATURA Y VIBRACIONES DE MOTOR

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Wimpie 0:9b5b3200688f 1 /*
Wimpie 0:9b5b3200688f 2 * DHT Library for Digital-output Humidity and Temperature sensors
Wimpie 0:9b5b3200688f 3 *
Wimpie 0:9b5b3200688f 4 * Works with DHT11, DHT22
Wimpie 0:9b5b3200688f 5 * SEN11301P, Grove - Temperature&Humidity Sensor (Seeed Studio)
Wimpie 0:9b5b3200688f 6 * SEN51035P, Grove - Temperature&Humidity Sensor Pro (Seeed Studio)
Wimpie 0:9b5b3200688f 7 * AM2302 , temperature-humidity sensor
Wimpie 0:9b5b3200688f 8 * HM2303 , Digital-output humidity and temperature sensor
Wimpie 0:9b5b3200688f 9 *
Wimpie 0:9b5b3200688f 10 * Copyright (C) Wim De Roeve
Wimpie 0:9b5b3200688f 11 * based on DHT22 sensor library by HO WING KIT
sam_grove 2:df22ddf10d75 12 * Arduino DHT11 library
Wimpie 0:9b5b3200688f 13 *
Wimpie 0:9b5b3200688f 14 * Permission is hereby granted, free of charge, to any person obtaining a copy
Wimpie 0:9b5b3200688f 15 * of this software and associated documnetation files (the "Software"), to deal
Wimpie 0:9b5b3200688f 16 * in the Software without restriction, including without limitation the rights
Wimpie 0:9b5b3200688f 17 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
Wimpie 0:9b5b3200688f 18 * copies of the Software, and to permit persons to whom the Software is
Wimpie 0:9b5b3200688f 19 * furished to do so, subject to the following conditions:
Wimpie 0:9b5b3200688f 20 *
Wimpie 0:9b5b3200688f 21 * The above copyright notice and this permission notice shall be included in
Wimpie 0:9b5b3200688f 22 * all copies or substantial portions of the Software.
Wimpie 0:9b5b3200688f 23 *
Wimpie 0:9b5b3200688f 24 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
Wimpie 0:9b5b3200688f 25 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
Wimpie 0:9b5b3200688f 26 * FITNESS OR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
Wimpie 0:9b5b3200688f 27 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
Wimpie 0:9b5b3200688f 28 * LIABILITY WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
Wimpie 0:9b5b3200688f 29 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
Wimpie 0:9b5b3200688f 30 * THE SOFTWARE.
Wimpie 0:9b5b3200688f 31 */
Wimpie 0:9b5b3200688f 32
Wimpie 0:9b5b3200688f 33 #include "DHT.h"
Wimpie 0:9b5b3200688f 34
sam_grove 2:df22ddf10d75 35 #define DHT_DATA_BIT_COUNT 40
Wimpie 0:9b5b3200688f 36
sam_grove 2:df22ddf10d75 37 DHT::DHT(PinName pin, eType DHTtype)
sam_grove 2:df22ddf10d75 38 {
Wimpie 0:9b5b3200688f 39 _pin = pin;
Wimpie 0:9b5b3200688f 40 _DHTtype = DHTtype;
sam_grove 2:df22ddf10d75 41 _firsttime = true;
sam_grove 2:df22ddf10d75 42 }
sam_grove 2:df22ddf10d75 43
sam_grove 2:df22ddf10d75 44 DHT::~DHT()
sam_grove 2:df22ddf10d75 45 {
sam_grove 2:df22ddf10d75 46
Wimpie 0:9b5b3200688f 47 }
Wimpie 0:9b5b3200688f 48
sam_grove 2:df22ddf10d75 49 eError DHT::stall(DigitalInOut &io, int const level, int const max_time)
sam_grove 2:df22ddf10d75 50 {
sam_grove 2:df22ddf10d75 51 int cnt = 0;
sam_grove 2:df22ddf10d75 52 while (level == io) {
sam_grove 2:df22ddf10d75 53 if (cnt > max_time) {
sam_grove 2:df22ddf10d75 54 return ERROR_NO_PATIENCE;
sam_grove 2:df22ddf10d75 55 }
sam_grove 2:df22ddf10d75 56 cnt++;
sam_grove 2:df22ddf10d75 57 wait_us(1);
sam_grove 2:df22ddf10d75 58 }
sam_grove 2:df22ddf10d75 59 return ERROR_NONE;
Wimpie 0:9b5b3200688f 60 }
Wimpie 0:9b5b3200688f 61
sam_grove 2:df22ddf10d75 62 eError DHT::readData()
sam_grove 2:df22ddf10d75 63 {
sam_grove 2:df22ddf10d75 64 uint8_t i = 0, j = 0, b = 0, data_valid = 0;
sam_grove 2:df22ddf10d75 65 uint32_t bit_value[DHT_DATA_BIT_COUNT] = {0};
Wimpie 0:9b5b3200688f 66
Wimpie 0:9b5b3200688f 67 eError err = ERROR_NONE;
Wimpie 0:9b5b3200688f 68 time_t currentTime = time(NULL);
Wimpie 0:9b5b3200688f 69
Wimpie 0:9b5b3200688f 70 DigitalInOut DHT_io(_pin);
Wimpie 0:9b5b3200688f 71
sam_grove 2:df22ddf10d75 72 // IO must be in hi state to start
sam_grove 2:df22ddf10d75 73 if (ERROR_NONE != stall(DHT_io, 0, 250)) {
sam_grove 2:df22ddf10d75 74 return BUS_BUSY;
Wimpie 0:9b5b3200688f 75 }
Wimpie 0:9b5b3200688f 76
sam_grove 2:df22ddf10d75 77 // start the transfer
Wimpie 0:9b5b3200688f 78 DHT_io.output();
Wimpie 0:9b5b3200688f 79 DHT_io = 0;
Sly_fox 5:cce2105f7365 80 wait_ms(18); // for DHT22 minimum 800µs but for DHT11 etc. 18ms are required
Wimpie 0:9b5b3200688f 81 DHT_io = 1;
sam_grove 2:df22ddf10d75 82 wait_us(30);
Wimpie 0:9b5b3200688f 83 DHT_io.input();
sam_grove 2:df22ddf10d75 84 // wait till the sensor grabs the bus
sam_grove 3:6937e130feca 85 if (ERROR_NONE != stall(DHT_io, 1, 100)) {
sam_grove 2:df22ddf10d75 86 return ERROR_NOT_PRESENT;
Wimpie 0:9b5b3200688f 87 }
sam_grove 2:df22ddf10d75 88 // sensor should signal low 80us and then hi 80us
sam_grove 2:df22ddf10d75 89 if (ERROR_NONE != stall(DHT_io, 0, 100)) {
sam_grove 2:df22ddf10d75 90 return ERROR_SYNC_TIMEOUT;
sam_grove 2:df22ddf10d75 91 }
sam_grove 2:df22ddf10d75 92 if (ERROR_NONE != stall(DHT_io, 1, 100)) {
sam_grove 2:df22ddf10d75 93 return ERROR_NO_PATIENCE;
sam_grove 2:df22ddf10d75 94 }
sam_grove 2:df22ddf10d75 95 // capture the data
Wimpie 0:9b5b3200688f 96 for (i = 0; i < 5; i++) {
Wimpie 0:9b5b3200688f 97 for (j = 0; j < 8; j++) {
sam_grove 2:df22ddf10d75 98 if (ERROR_NONE != stall(DHT_io, 0, 75)) {
sam_grove 2:df22ddf10d75 99 return ERROR_DATA_TIMEOUT;
sam_grove 2:df22ddf10d75 100 }
sam_grove 2:df22ddf10d75 101 // logic 0 is 28us max, 1 is 70us
Wimpie 0:9b5b3200688f 102 wait_us(40);
sam_grove 2:df22ddf10d75 103 bit_value[i*8+j] = DHT_io;
sam_grove 2:df22ddf10d75 104 if (ERROR_NONE != stall(DHT_io, 1, 50)) {
sam_grove 2:df22ddf10d75 105 return ERROR_DATA_TIMEOUT;
Wimpie 0:9b5b3200688f 106 }
Wimpie 0:9b5b3200688f 107 }
Wimpie 0:9b5b3200688f 108 }
sam_grove 2:df22ddf10d75 109 // store the data
Wimpie 0:9b5b3200688f 110 for (i = 0; i < 5; i++) {
Wimpie 0:9b5b3200688f 111 b=0;
Wimpie 0:9b5b3200688f 112 for (j=0; j<8; j++) {
sam_grove 2:df22ddf10d75 113 if (bit_value[i*8+j] == 1) {
sam_grove 2:df22ddf10d75 114 b |= (1 << (7-j));
Wimpie 0:9b5b3200688f 115 }
Wimpie 0:9b5b3200688f 116 }
Wimpie 0:9b5b3200688f 117 DHT_data[i]=b;
Wimpie 0:9b5b3200688f 118 }
Wimpie 0:9b5b3200688f 119
sam_grove 2:df22ddf10d75 120 // uncomment to see the checksum error if it exists
Sly_fox 4:0667c68ef5e0 121 // printf(" 0x%02x + 0x%02x + 0x%02x + 0x%02x = 0x%02x \n", DHT_data[0], DHT_data[1], DHT_data[2], DHT_data[3], DHT_data[4]);
sam_grove 2:df22ddf10d75 122 data_valid = DHT_data[0] + DHT_data[1] + DHT_data[2] + DHT_data[3];
sam_grove 2:df22ddf10d75 123 if (DHT_data[4] == data_valid) {
Wimpie 0:9b5b3200688f 124 _lastReadTime = currentTime;
sam_grove 2:df22ddf10d75 125 _lastTemperature = CalcTemperature();
sam_grove 2:df22ddf10d75 126 _lastHumidity = CalcHumidity();
Wimpie 0:9b5b3200688f 127
Wimpie 0:9b5b3200688f 128 } else {
Wimpie 0:9b5b3200688f 129 err = ERROR_CHECKSUM;
Wimpie 0:9b5b3200688f 130 }
Wimpie 0:9b5b3200688f 131
Wimpie 0:9b5b3200688f 132 return err;
Wimpie 0:9b5b3200688f 133
Wimpie 0:9b5b3200688f 134 }
Wimpie 0:9b5b3200688f 135
Sly_fox 5:cce2105f7365 136
Sly_fox 5:cce2105f7365 137
Sly_fox 5:cce2105f7365 138
Sly_fox 5:cce2105f7365 139
sam_grove 2:df22ddf10d75 140 float DHT::CalcTemperature()
sam_grove 2:df22ddf10d75 141 {
Sly_fox 4:0667c68ef5e0 142 float v;
Wimpie 0:9b5b3200688f 143
Wimpie 0:9b5b3200688f 144 switch (_DHTtype) {
Wimpie 0:9b5b3200688f 145 case DHT11:
Wimpie 0:9b5b3200688f 146 v = DHT_data[2];
Wimpie 0:9b5b3200688f 147 return float(v);
Wimpie 0:9b5b3200688f 148 case DHT22:
Sly_fox 5:cce2105f7365 149 // to calculate temperture of DHT22 in Celsius = (DHT_data[2]*256 + DHT_data[3]) / 10
Sly_fox 5:cce2105f7365 150 // if first bit of DHT_data[2] is 1 then the temperature is negative.
Sly_fox 5:cce2105f7365 151
Sly_fox 5:cce2105f7365 152
Sly_fox 5:cce2105f7365 153 v = DHT_data[2] & 0x7F; // mask of the bit for negative temperture
Wimpie 0:9b5b3200688f 154 v *= 256;
Wimpie 0:9b5b3200688f 155 v += DHT_data[3];
Wimpie 0:9b5b3200688f 156 v /= 10;
Sly_fox 5:cce2105f7365 157 if (DHT_data[2] & 0x80) // if first bit of DHT_data[2] is 1 then the temperature is negative.
Wimpie 0:9b5b3200688f 158 v *= -1;
flozada 6:b3ec6bbb9565 159 v=v/28;
Wimpie 0:9b5b3200688f 160 return float(v);
Wimpie 0:9b5b3200688f 161 }
Wimpie 0:9b5b3200688f 162 return 0;
Wimpie 0:9b5b3200688f 163 }
Wimpie 0:9b5b3200688f 164
sam_grove 2:df22ddf10d75 165 float DHT::ReadHumidity()
sam_grove 2:df22ddf10d75 166 {
Wimpie 0:9b5b3200688f 167 return _lastHumidity;
Wimpie 0:9b5b3200688f 168 }
Wimpie 0:9b5b3200688f 169
sam_grove 2:df22ddf10d75 170 float DHT::ConvertCelciustoFarenheit(float const celsius)
sam_grove 2:df22ddf10d75 171 {
Wimpie 0:9b5b3200688f 172 return celsius * 9 / 5 + 32;
Wimpie 0:9b5b3200688f 173 }
Wimpie 0:9b5b3200688f 174
sam_grove 2:df22ddf10d75 175 float DHT::ConvertCelciustoKelvin(float const celsius)
sam_grove 2:df22ddf10d75 176 {
sam_grove 3:6937e130feca 177 return celsius + 273.15f;
Wimpie 0:9b5b3200688f 178 }
Wimpie 0:9b5b3200688f 179
Wimpie 0:9b5b3200688f 180 // dewPoint function NOAA
Wimpie 0:9b5b3200688f 181 // reference: http://wahiduddin.net/calc/density_algorithms.htm
sam_grove 2:df22ddf10d75 182 float DHT::CalcdewPoint(float const celsius, float const humidity)
sam_grove 2:df22ddf10d75 183 {
sam_grove 3:6937e130feca 184 float A0= 373.15f/(273.15f + celsius);
Wimpie 0:9b5b3200688f 185 float SUM = -7.90298 * (A0-1);
sam_grove 3:6937e130feca 186 SUM += 5.02808f * log10(A0);
sam_grove 3:6937e130feca 187 SUM += -1.3816e-7 * (pow(10, (11.344f*(1-1/A0)))-1) ;
Wimpie 0:9b5b3200688f 188 SUM += 8.1328e-3 * (pow(10,(-3.49149*(A0-1)))-1) ;
Wimpie 0:9b5b3200688f 189 SUM += log10(1013.246);
Wimpie 0:9b5b3200688f 190 float VP = pow(10, SUM-3) * humidity;
sam_grove 3:6937e130feca 191 float T = log(VP/0.61078f); // temp var
sam_grove 3:6937e130feca 192 return (241.88f * T) / (17.558f-T);
Wimpie 0:9b5b3200688f 193 }
Wimpie 0:9b5b3200688f 194
Wimpie 0:9b5b3200688f 195 // delta max = 0.6544 wrt dewPoint()
Wimpie 0:9b5b3200688f 196 // 5x faster than dewPoint()
Wimpie 0:9b5b3200688f 197 // reference: http://en.wikipedia.org/wiki/Dew_point
sam_grove 2:df22ddf10d75 198 float DHT::CalcdewPointFast(float const celsius, float const humidity)
Wimpie 0:9b5b3200688f 199 {
sam_grove 2:df22ddf10d75 200 float a = 17.271;
sam_grove 2:df22ddf10d75 201 float b = 237.7;
sam_grove 2:df22ddf10d75 202 float temp = (a * celsius) / (b + celsius) + log(humidity/100);
sam_grove 2:df22ddf10d75 203 float Td = (b * temp) / (a - temp);
sam_grove 2:df22ddf10d75 204 return Td;
Wimpie 0:9b5b3200688f 205 }
Wimpie 0:9b5b3200688f 206
sam_grove 2:df22ddf10d75 207 float DHT::ReadTemperature(eScale Scale)
sam_grove 2:df22ddf10d75 208 {
Wimpie 0:9b5b3200688f 209 if (Scale == FARENHEIT)
Wimpie 0:9b5b3200688f 210 return ConvertCelciustoFarenheit(_lastTemperature);
Wimpie 0:9b5b3200688f 211 else if (Scale == KELVIN)
Wimpie 0:9b5b3200688f 212 return ConvertCelciustoKelvin(_lastTemperature);
Wimpie 0:9b5b3200688f 213 else
Wimpie 0:9b5b3200688f 214 return _lastTemperature;
Wimpie 0:9b5b3200688f 215 }
Wimpie 0:9b5b3200688f 216
sam_grove 2:df22ddf10d75 217 float DHT::CalcHumidity()
sam_grove 2:df22ddf10d75 218 {
Sly_fox 4:0667c68ef5e0 219 float v; // needs to be float for DHT22 otherwise only zero after decimal point
Wimpie 0:9b5b3200688f 220 switch (_DHTtype) {
Wimpie 0:9b5b3200688f 221 case DHT11:
Wimpie 0:9b5b3200688f 222 v = DHT_data[0];
Wimpie 0:9b5b3200688f 223 return float(v);
Wimpie 0:9b5b3200688f 224 case DHT22:
Sly_fox 5:cce2105f7365 225 // to calculate humidity of DHT22 = (DHT_data[0]*256 + DHT_data[1]) / 10
Wimpie 0:9b5b3200688f 226 v = DHT_data[0];
Wimpie 0:9b5b3200688f 227 v *= 256;
Wimpie 0:9b5b3200688f 228 v += DHT_data[1];
Wimpie 0:9b5b3200688f 229 v /= 10;
Wimpie 0:9b5b3200688f 230 return float(v);
Wimpie 0:9b5b3200688f 231 }
Wimpie 0:9b5b3200688f 232 return 0;
Wimpie 0:9b5b3200688f 233 }
Wimpie 0:9b5b3200688f 234
Wimpie 0:9b5b3200688f 235