This a domestic weather station that measures temperature, humidity and light and stores the data in a .csv file in SD card.
Dependencies: DS1302 SDFileSystem mbed
Fork of temp_humid_light_time_DS1302_LM35_DHT11_LDR by
DHT.cpp@0:8f0934e41a57, 2014-07-04 (annotated)
- Committer:
- Clovis
- Date:
- Fri Jul 04 08:08:38 2014 +0000
- Revision:
- 0:8f0934e41a57
Datalogger for temperature, humidity and light level, using a FRDM-K64F development board by Freescale and storing data on a microSD card. It keeps track of the time by means of a DS1302 timekeeping chip.
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
Clovis | 0:8f0934e41a57 | 1 | /* |
Clovis | 0:8f0934e41a57 | 2 | * DHT Library for Digital-output Humidity and Temperature sensors |
Clovis | 0:8f0934e41a57 | 3 | * |
Clovis | 0:8f0934e41a57 | 4 | * Works with DHT11, DHT22 |
Clovis | 0:8f0934e41a57 | 5 | * SEN11301P, Grove - Temperature&Humidity Sensor (Seeed Studio) |
Clovis | 0:8f0934e41a57 | 6 | * SEN51035P, Grove - Temperature&Humidity Sensor Pro (Seeed Studio) |
Clovis | 0:8f0934e41a57 | 7 | * AM2302 , temperature-humidity sensor |
Clovis | 0:8f0934e41a57 | 8 | * HM2303 , Digital-output humidity and temperature sensor |
Clovis | 0:8f0934e41a57 | 9 | * |
Clovis | 0:8f0934e41a57 | 10 | * Copyright (C) Wim De Roeve |
Clovis | 0:8f0934e41a57 | 11 | * based on DHT22 sensor library by HO WING KIT |
Clovis | 0:8f0934e41a57 | 12 | * Arduino DHT11 library |
Clovis | 0:8f0934e41a57 | 13 | * |
Clovis | 0:8f0934e41a57 | 14 | * Permission is hereby granted, free of charge, to any person obtaining a copy |
Clovis | 0:8f0934e41a57 | 15 | * of this software and associated documnetation files (the "Software"), to deal |
Clovis | 0:8f0934e41a57 | 16 | * in the Software without restriction, including without limitation the rights |
Clovis | 0:8f0934e41a57 | 17 | * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
Clovis | 0:8f0934e41a57 | 18 | * copies of the Software, and to permit persons to whom the Software is |
Clovis | 0:8f0934e41a57 | 19 | * furished to do so, subject to the following conditions: |
Clovis | 0:8f0934e41a57 | 20 | * |
Clovis | 0:8f0934e41a57 | 21 | * The above copyright notice and this permission notice shall be included in |
Clovis | 0:8f0934e41a57 | 22 | * all copies or substantial portions of the Software. |
Clovis | 0:8f0934e41a57 | 23 | * |
Clovis | 0:8f0934e41a57 | 24 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
Clovis | 0:8f0934e41a57 | 25 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
Clovis | 0:8f0934e41a57 | 26 | * FITNESS OR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
Clovis | 0:8f0934e41a57 | 27 | * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
Clovis | 0:8f0934e41a57 | 28 | * LIABILITY WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
Clovis | 0:8f0934e41a57 | 29 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN |
Clovis | 0:8f0934e41a57 | 30 | * THE SOFTWARE. |
Clovis | 0:8f0934e41a57 | 31 | */ |
Clovis | 0:8f0934e41a57 | 32 | |
Clovis | 0:8f0934e41a57 | 33 | #include "DHT.h" |
Clovis | 0:8f0934e41a57 | 34 | |
Clovis | 0:8f0934e41a57 | 35 | #define DHT_DATA_BIT_COUNT 40 |
Clovis | 0:8f0934e41a57 | 36 | int data0= 0; |
Clovis | 0:8f0934e41a57 | 37 | int data2= 0; |
Clovis | 0:8f0934e41a57 | 38 | |
Clovis | 0:8f0934e41a57 | 39 | DHT::DHT(PinName pin,int DHTtype) { |
Clovis | 0:8f0934e41a57 | 40 | _pin = pin; |
Clovis | 0:8f0934e41a57 | 41 | _DHTtype = DHTtype; |
Clovis | 0:8f0934e41a57 | 42 | _firsttime=true; |
Clovis | 0:8f0934e41a57 | 43 | } |
Clovis | 0:8f0934e41a57 | 44 | |
Clovis | 0:8f0934e41a57 | 45 | DHT::~DHT() { |
Clovis | 0:8f0934e41a57 | 46 | } |
Clovis | 0:8f0934e41a57 | 47 | |
Clovis | 0:8f0934e41a57 | 48 | int DHT::readData() { |
Clovis | 0:8f0934e41a57 | 49 | int i, j, retryCount,b; |
Clovis | 0:8f0934e41a57 | 50 | unsigned int bitTimes[DHT_DATA_BIT_COUNT]; |
Clovis | 0:8f0934e41a57 | 51 | |
Clovis | 0:8f0934e41a57 | 52 | eError err = ERROR_NONE; |
Clovis | 0:8f0934e41a57 | 53 | time_t currentTime = time(NULL); |
Clovis | 0:8f0934e41a57 | 54 | |
Clovis | 0:8f0934e41a57 | 55 | DigitalInOut DHT_io(_pin); |
Clovis | 0:8f0934e41a57 | 56 | |
Clovis | 0:8f0934e41a57 | 57 | for (i = 0; i < DHT_DATA_BIT_COUNT; i++) { |
Clovis | 0:8f0934e41a57 | 58 | bitTimes[i] = 0; |
Clovis | 0:8f0934e41a57 | 59 | } |
Clovis | 0:8f0934e41a57 | 60 | |
Clovis | 0:8f0934e41a57 | 61 | if (!_firsttime) { |
Clovis | 0:8f0934e41a57 | 62 | if (int(currentTime - _lastReadTime) < 2) { |
Clovis | 0:8f0934e41a57 | 63 | err = ERROR_NO_PATIENCE; |
Clovis | 0:8f0934e41a57 | 64 | return err; |
Clovis | 0:8f0934e41a57 | 65 | } |
Clovis | 0:8f0934e41a57 | 66 | } else { |
Clovis | 0:8f0934e41a57 | 67 | _firsttime=false; |
Clovis | 0:8f0934e41a57 | 68 | _lastReadTime=currentTime; |
Clovis | 0:8f0934e41a57 | 69 | } |
Clovis | 0:8f0934e41a57 | 70 | retryCount = 0; |
Clovis | 0:8f0934e41a57 | 71 | |
Clovis | 0:8f0934e41a57 | 72 | do { |
Clovis | 0:8f0934e41a57 | 73 | if (retryCount > 125) { |
Clovis | 0:8f0934e41a57 | 74 | err = BUS_BUSY; |
Clovis | 0:8f0934e41a57 | 75 | return err; |
Clovis | 0:8f0934e41a57 | 76 | } |
Clovis | 0:8f0934e41a57 | 77 | retryCount ++; |
Clovis | 0:8f0934e41a57 | 78 | wait_us(2); |
Clovis | 0:8f0934e41a57 | 79 | } while ((DHT_io==0)); |
Clovis | 0:8f0934e41a57 | 80 | |
Clovis | 0:8f0934e41a57 | 81 | |
Clovis | 0:8f0934e41a57 | 82 | DHT_io.output(); |
Clovis | 0:8f0934e41a57 | 83 | DHT_io = 0; |
Clovis | 0:8f0934e41a57 | 84 | wait_ms(18); |
Clovis | 0:8f0934e41a57 | 85 | DHT_io = 1; |
Clovis | 0:8f0934e41a57 | 86 | wait_us(40); |
Clovis | 0:8f0934e41a57 | 87 | DHT_io.input(); |
Clovis | 0:8f0934e41a57 | 88 | |
Clovis | 0:8f0934e41a57 | 89 | retryCount = 0; |
Clovis | 0:8f0934e41a57 | 90 | do { |
Clovis | 0:8f0934e41a57 | 91 | if (retryCount > 40) { |
Clovis | 0:8f0934e41a57 | 92 | err = ERROR_NOT_PRESENT; |
Clovis | 0:8f0934e41a57 | 93 | return err; |
Clovis | 0:8f0934e41a57 | 94 | } |
Clovis | 0:8f0934e41a57 | 95 | retryCount++; |
Clovis | 0:8f0934e41a57 | 96 | wait_us(1); |
Clovis | 0:8f0934e41a57 | 97 | } while ((DHT_io==1)); |
Clovis | 0:8f0934e41a57 | 98 | |
Clovis | 0:8f0934e41a57 | 99 | if (err != ERROR_NONE) { |
Clovis | 0:8f0934e41a57 | 100 | return err; |
Clovis | 0:8f0934e41a57 | 101 | } |
Clovis | 0:8f0934e41a57 | 102 | |
Clovis | 0:8f0934e41a57 | 103 | wait_us(80); |
Clovis | 0:8f0934e41a57 | 104 | |
Clovis | 0:8f0934e41a57 | 105 | for (i = 0; i < 5; i++) { |
Clovis | 0:8f0934e41a57 | 106 | for (j = 0; j < 8; j++) { |
Clovis | 0:8f0934e41a57 | 107 | |
Clovis | 0:8f0934e41a57 | 108 | retryCount = 0; |
Clovis | 0:8f0934e41a57 | 109 | do { |
Clovis | 0:8f0934e41a57 | 110 | if (retryCount > 75) { |
Clovis | 0:8f0934e41a57 | 111 | err = ERROR_DATA_TIMEOUT; |
Clovis | 0:8f0934e41a57 | 112 | return err; |
Clovis | 0:8f0934e41a57 | 113 | } |
Clovis | 0:8f0934e41a57 | 114 | retryCount++; |
Clovis | 0:8f0934e41a57 | 115 | wait_us(1); |
Clovis | 0:8f0934e41a57 | 116 | } while (DHT_io == 0); |
Clovis | 0:8f0934e41a57 | 117 | wait_us(40); |
Clovis | 0:8f0934e41a57 | 118 | bitTimes[i*8+j]=DHT_io; |
Clovis | 0:8f0934e41a57 | 119 | |
Clovis | 0:8f0934e41a57 | 120 | int count = 0; |
Clovis | 0:8f0934e41a57 | 121 | while (DHT_io == 1 && count < 100) { |
Clovis | 0:8f0934e41a57 | 122 | wait_us(1); |
Clovis | 0:8f0934e41a57 | 123 | count++; |
Clovis | 0:8f0934e41a57 | 124 | } |
Clovis | 0:8f0934e41a57 | 125 | } |
Clovis | 0:8f0934e41a57 | 126 | } |
Clovis | 0:8f0934e41a57 | 127 | DHT_io.output(); |
Clovis | 0:8f0934e41a57 | 128 | DHT_io = 1; |
Clovis | 0:8f0934e41a57 | 129 | for (i = 0; i < 5; i++) { |
Clovis | 0:8f0934e41a57 | 130 | b=0; |
Clovis | 0:8f0934e41a57 | 131 | for (j=0; j<8; j++) { |
Clovis | 0:8f0934e41a57 | 132 | if (bitTimes[i*8+j+1] > 0) { |
Clovis | 0:8f0934e41a57 | 133 | b |= ( 1 << (7-j)); |
Clovis | 0:8f0934e41a57 | 134 | } |
Clovis | 0:8f0934e41a57 | 135 | } |
Clovis | 0:8f0934e41a57 | 136 | DHT_data[i]=b; |
Clovis | 0:8f0934e41a57 | 137 | } |
Clovis | 0:8f0934e41a57 | 138 | |
Clovis | 0:8f0934e41a57 | 139 | data2= DHT_data[2]; |
Clovis | 0:8f0934e41a57 | 140 | data0= DHT_data[0]; |
Clovis | 0:8f0934e41a57 | 141 | |
Clovis | 0:8f0934e41a57 | 142 | if ((data2 + data0)%2 == 0){ //This IF statement corrects the "Err 6" issue |
Clovis | 0:8f0934e41a57 | 143 | data0= data0+1; |
Clovis | 0:8f0934e41a57 | 144 | } |
Clovis | 0:8f0934e41a57 | 145 | |
Clovis | 0:8f0934e41a57 | 146 | if (DHT_data[4] == ((data0 + DHT_data[1] + data2 + DHT_data[3]) & 0xFF)) { |
Clovis | 0:8f0934e41a57 | 147 | _lastReadTime = currentTime; |
Clovis | 0:8f0934e41a57 | 148 | _lastTemperature=CalcTemperature(); |
Clovis | 0:8f0934e41a57 | 149 | _lastHumidity=CalcHumidity(); |
Clovis | 0:8f0934e41a57 | 150 | |
Clovis | 0:8f0934e41a57 | 151 | } else { |
Clovis | 0:8f0934e41a57 | 152 | err = ERROR_CHECKSUM; |
Clovis | 0:8f0934e41a57 | 153 | } |
Clovis | 0:8f0934e41a57 | 154 | |
Clovis | 0:8f0934e41a57 | 155 | return err; |
Clovis | 0:8f0934e41a57 | 156 | |
Clovis | 0:8f0934e41a57 | 157 | } |
Clovis | 0:8f0934e41a57 | 158 | |
Clovis | 0:8f0934e41a57 | 159 | float DHT::CalcTemperature() { |
Clovis | 0:8f0934e41a57 | 160 | int v; |
Clovis | 0:8f0934e41a57 | 161 | |
Clovis | 0:8f0934e41a57 | 162 | switch (_DHTtype) { |
Clovis | 0:8f0934e41a57 | 163 | case DHT11: |
Clovis | 0:8f0934e41a57 | 164 | v = DHT_data[2]; |
Clovis | 0:8f0934e41a57 | 165 | return float(v); |
Clovis | 0:8f0934e41a57 | 166 | case DHT22: |
Clovis | 0:8f0934e41a57 | 167 | v = DHT_data[2] & 0x7F; |
Clovis | 0:8f0934e41a57 | 168 | v *= 256; |
Clovis | 0:8f0934e41a57 | 169 | v += DHT_data[3]; |
Clovis | 0:8f0934e41a57 | 170 | v /= 10; |
Clovis | 0:8f0934e41a57 | 171 | if (DHT_data[2] & 0x80) |
Clovis | 0:8f0934e41a57 | 172 | v *= -1; |
Clovis | 0:8f0934e41a57 | 173 | return float(v); |
Clovis | 0:8f0934e41a57 | 174 | } |
Clovis | 0:8f0934e41a57 | 175 | return 0; |
Clovis | 0:8f0934e41a57 | 176 | } |
Clovis | 0:8f0934e41a57 | 177 | |
Clovis | 0:8f0934e41a57 | 178 | float DHT::ReadHumidity() { |
Clovis | 0:8f0934e41a57 | 179 | return _lastHumidity; |
Clovis | 0:8f0934e41a57 | 180 | } |
Clovis | 0:8f0934e41a57 | 181 | |
Clovis | 0:8f0934e41a57 | 182 | float DHT::ConvertCelciustoFarenheit(float celsius) { |
Clovis | 0:8f0934e41a57 | 183 | return celsius * 9 / 5 + 32; |
Clovis | 0:8f0934e41a57 | 184 | } |
Clovis | 0:8f0934e41a57 | 185 | |
Clovis | 0:8f0934e41a57 | 186 | float DHT::ConvertCelciustoKelvin(float celsius) { |
Clovis | 0:8f0934e41a57 | 187 | return celsius + 273.15; |
Clovis | 0:8f0934e41a57 | 188 | } |
Clovis | 0:8f0934e41a57 | 189 | |
Clovis | 0:8f0934e41a57 | 190 | // dewPoint function NOAA |
Clovis | 0:8f0934e41a57 | 191 | // reference: http://wahiduddin.net/calc/density_algorithms.htm |
Clovis | 0:8f0934e41a57 | 192 | float DHT::CalcdewPoint(float celsius, float humidity) { |
Clovis | 0:8f0934e41a57 | 193 | float A0= 373.15/(273.15 + celsius); |
Clovis | 0:8f0934e41a57 | 194 | float SUM = -7.90298 * (A0-1); |
Clovis | 0:8f0934e41a57 | 195 | SUM += 5.02808 * log10(A0); |
Clovis | 0:8f0934e41a57 | 196 | SUM += -1.3816e-7 * (pow(10, (11.344*(1-1/A0)))-1) ; |
Clovis | 0:8f0934e41a57 | 197 | SUM += 8.1328e-3 * (pow(10,(-3.49149*(A0-1)))-1) ; |
Clovis | 0:8f0934e41a57 | 198 | SUM += log10(1013.246); |
Clovis | 0:8f0934e41a57 | 199 | float VP = pow(10, SUM-3) * humidity; |
Clovis | 0:8f0934e41a57 | 200 | float T = log(VP/0.61078); // temp var |
Clovis | 0:8f0934e41a57 | 201 | return (241.88 * T) / (17.558-T); |
Clovis | 0:8f0934e41a57 | 202 | } |
Clovis | 0:8f0934e41a57 | 203 | |
Clovis | 0:8f0934e41a57 | 204 | // delta max = 0.6544 wrt dewPoint() |
Clovis | 0:8f0934e41a57 | 205 | // 5x faster than dewPoint() |
Clovis | 0:8f0934e41a57 | 206 | // reference: http://en.wikipedia.org/wiki/Dew_point |
Clovis | 0:8f0934e41a57 | 207 | float DHT::CalcdewPointFast(float celsius, float humidity) |
Clovis | 0:8f0934e41a57 | 208 | { |
Clovis | 0:8f0934e41a57 | 209 | float a = 17.271; |
Clovis | 0:8f0934e41a57 | 210 | float b = 237.7; |
Clovis | 0:8f0934e41a57 | 211 | float temp = (a * celsius) / (b + celsius) + log(humidity/100); |
Clovis | 0:8f0934e41a57 | 212 | float Td = (b * temp) / (a - temp); |
Clovis | 0:8f0934e41a57 | 213 | return Td; |
Clovis | 0:8f0934e41a57 | 214 | } |
Clovis | 0:8f0934e41a57 | 215 | |
Clovis | 0:8f0934e41a57 | 216 | float DHT::ReadTemperature(eScale Scale) { |
Clovis | 0:8f0934e41a57 | 217 | if (Scale == FARENHEIT) |
Clovis | 0:8f0934e41a57 | 218 | return ConvertCelciustoFarenheit(_lastTemperature); |
Clovis | 0:8f0934e41a57 | 219 | else if (Scale == KELVIN) |
Clovis | 0:8f0934e41a57 | 220 | return ConvertCelciustoKelvin(_lastTemperature); |
Clovis | 0:8f0934e41a57 | 221 | else |
Clovis | 0:8f0934e41a57 | 222 | return _lastTemperature; |
Clovis | 0:8f0934e41a57 | 223 | } |
Clovis | 0:8f0934e41a57 | 224 | |
Clovis | 0:8f0934e41a57 | 225 | float DHT::CalcHumidity() { |
Clovis | 0:8f0934e41a57 | 226 | int v; |
Clovis | 0:8f0934e41a57 | 227 | |
Clovis | 0:8f0934e41a57 | 228 | switch (_DHTtype) { |
Clovis | 0:8f0934e41a57 | 229 | case DHT11: |
Clovis | 0:8f0934e41a57 | 230 | v = DHT_data[0]; |
Clovis | 0:8f0934e41a57 | 231 | return float(v); |
Clovis | 0:8f0934e41a57 | 232 | case DHT22: |
Clovis | 0:8f0934e41a57 | 233 | v = DHT_data[0]; |
Clovis | 0:8f0934e41a57 | 234 | v *= 256; |
Clovis | 0:8f0934e41a57 | 235 | v += DHT_data[1]; |
Clovis | 0:8f0934e41a57 | 236 | v /= 10; |
Clovis | 0:8f0934e41a57 | 237 | return float(v); |
Clovis | 0:8f0934e41a57 | 238 | } |
Clovis | 0:8f0934e41a57 | 239 | return 0; |
Clovis | 0:8f0934e41a57 | 240 | } |
Clovis | 0:8f0934e41a57 | 241 | |
Clovis | 0:8f0934e41a57 | 242 |