Manuel Caballero / DHT11

DHT11 Temperature & Humidity Sensor features a temperature & humidity sensor complex with a calibrated digital signal output.

DHT11.h@4:889926e2b6a5, 2019-08-09 (annotated)

Committer:
mcm
Date:
Fri Aug 09 07:39:17 2019 +0000
Revision:
4:889926e2b6a5
Parent:
3:082a970dca06 
An example was added in order to show how to use this driver.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mcm 1:ff93ee72c7a1 1 /**
mcm 1:ff93ee72c7a1 2 * @brief DHT11.h
mcm 1:ff93ee72c7a1 3 * @details Temperature & humidity sensor complex with a calibrated digital signal output.
mcm 1:ff93ee72c7a1 4 * Header file.
mcm 1:ff93ee72c7a1 5 *
mcm 1:ff93ee72c7a1 6 *
mcm 1:ff93ee72c7a1 7 * @return N/A
mcm 1:ff93ee72c7a1 8 *
mcm 1:ff93ee72c7a1 9 * @author Manuel Caballero
mcm 1:ff93ee72c7a1 10 * @date 08/August/2019
mcm 1:ff93ee72c7a1 11 * @version 08/August/2019 The ORIGIN
mcm 1:ff93ee72c7a1 12 * @pre N/A
mcm 1:ff93ee72c7a1 13 * @warning N/A
mcm 1:ff93ee72c7a1 14 * @pre This code belongs to AqueronteBlog ( http://unbarquero.blogspot.com ).
mcm 1:ff93ee72c7a1 15 */
mcm 1:ff93ee72c7a1 16 #ifndef DHT11_H_
mcm 1:ff93ee72c7a1 17 #define DHT11_H_
mcm 1:ff93ee72c7a1 18
mcm 1:ff93ee72c7a1 19 #include "mbed.h"
mcm 1:ff93ee72c7a1 20
mcm 1:ff93ee72c7a1 21
mcm 1:ff93ee72c7a1 22 /**
mcm 1:ff93ee72c7a1 23 Example:
mcm 1:ff93ee72c7a1 24
mcm 1:ff93ee72c7a1 25 @code
mcm 4:889926e2b6a5 26 #include "mbed.h"
mcm 4:889926e2b6a5 27 #include "DHT11.h"
mcm 1:ff93ee72c7a1 28
mcm 4:889926e2b6a5 29 DHT11 myDHT11 ( PB_8 ); // DHT11 --> PB_8
mcm 4:889926e2b6a5 30 Serial pc ( USBTX, USBRX ); // tx, rx
mcm 4:889926e2b6a5 31
mcm 4:889926e2b6a5 32 DigitalOut myled ( LED1 );
mcm 4:889926e2b6a5 33 Ticker newAction;
mcm 4:889926e2b6a5 34
mcm 4:889926e2b6a5 35
mcm 4:889926e2b6a5 36 //@brief Constants.
mcm 4:889926e2b6a5 37
mcm 4:889926e2b6a5 38
mcm 4:889926e2b6a5 39 //@brief Variables.
mcm 4:889926e2b6a5 40 volatile uint32_t myState; // State that indicates when to perform a new sample
mcm 4:889926e2b6a5 41
mcm 4:889926e2b6a5 42
mcm 4:889926e2b6a5 43 //@brief FUNCTION PROTOTYPES
mcm 4:889926e2b6a5 44 void changeDATA ( void );
mcm 4:889926e2b6a5 45
mcm 4:889926e2b6a5 46
mcm 4:889926e2b6a5 47 //@brief FUNCTION FOR APPLICATION MAIN ENTRY.
mcm 4:889926e2b6a5 48 int main()
mcm 4:889926e2b6a5 49 {
mcm 4:889926e2b6a5 50 char myChecksum[] = "Ok";
mcm 4:889926e2b6a5 51 DHT11::DHT11_status_t aux;
mcm 4:889926e2b6a5 52 DHT11::DHT11_data_t myDHT11_Data;
mcm 4:889926e2b6a5 53
mcm 4:889926e2b6a5 54 pc.baud ( 115200 );
mcm 4:889926e2b6a5 55
mcm 4:889926e2b6a5 56 myled = 1;
mcm 4:889926e2b6a5 57 wait(3);
mcm 4:889926e2b6a5 58 myled = 0;
mcm 4:889926e2b6a5 59
mcm 4:889926e2b6a5 60 // DHT11 starts: Release the bus
mcm 4:889926e2b6a5 61 aux = myDHT11.DHT11_Init ();
mcm 4:889926e2b6a5 62
mcm 4:889926e2b6a5 63
mcm 4:889926e2b6a5 64 myState = 0UL; // Reset the variable
mcm 4:889926e2b6a5 65 newAction.attach( &changeDATA, 1U ); // the address of the function to be attached ( changeDATA ) and the interval ( 1s )
mcm 4:889926e2b6a5 66
mcm 4:889926e2b6a5 67
mcm 4:889926e2b6a5 68 // Let the callbacks take care of everything
mcm 4:889926e2b6a5 69 while(1) {
mcm 4:889926e2b6a5 70 sleep();
mcm 4:889926e2b6a5 71
mcm 4:889926e2b6a5 72 if ( myState == 1UL ) {
mcm 4:889926e2b6a5 73 myled = 1U;
mcm 4:889926e2b6a5 74
mcm 4:889926e2b6a5 75 // Get a new data
mcm 4:889926e2b6a5 76 aux = myDHT11.DHT11_GetData ( &myDHT11_Data );
mcm 4:889926e2b6a5 77
mcm 4:889926e2b6a5 78 // Check checksum to validate data
mcm 4:889926e2b6a5 79 if ( myDHT11_Data.checksumStatus == DHT11::DHT11_CHECKSUM_OK ) {
mcm 4:889926e2b6a5 80 myChecksum[0] = 'O';
mcm 4:889926e2b6a5 81 myChecksum[1] = 'k';
mcm 4:889926e2b6a5 82 } else {
mcm 4:889926e2b6a5 83 myChecksum[0] = 'E';
mcm 4:889926e2b6a5 84 myChecksum[1] = 'r';
mcm 4:889926e2b6a5 85 }
mcm 4:889926e2b6a5 86
mcm 4:889926e2b6a5 87 // Send data through the UART
mcm 4:889926e2b6a5 88 pc.printf ( "T: %d C | RH: %d %% | Checksum: %s\r\n", myDHT11_Data.temperature, myDHT11_Data.humidity, myChecksum );
mcm 4:889926e2b6a5 89
mcm 4:889926e2b6a5 90
mcm 4:889926e2b6a5 91 // Reset the variables
mcm 4:889926e2b6a5 92 myState = 0UL;
mcm 4:889926e2b6a5 93 myled = 0U;
mcm 4:889926e2b6a5 94 }
mcm 4:889926e2b6a5 95 }
mcm 4:889926e2b6a5 96 }
mcm 4:889926e2b6a5 97
mcm 4:889926e2b6a5 98
mcm 4:889926e2b6a5 99 // @brief changeDATA ( void )
mcm 4:889926e2b6a5 100 //
mcm 4:889926e2b6a5 101 // @details It changes myState variable
mcm 4:889926e2b6a5 102 //
mcm 4:889926e2b6a5 103 // @param[in] N/A
mcm 4:889926e2b6a5 104 //
mcm 4:889926e2b6a5 105 // @param[out] N/A.
mcm 4:889926e2b6a5 106 //
mcm 4:889926e2b6a5 107 // @return N/A.
mcm 4:889926e2b6a5 108 //
mcm 4:889926e2b6a5 109 // @author Manuel Caballero
mcm 4:889926e2b6a5 110 // @date 24/June/2019
mcm 4:889926e2b6a5 111 // @version 24/June/2019 The ORIGIN
mcm 4:889926e2b6a5 112 // @pre N/A
mcm 4:889926e2b6a5 113 // @warning N/A.
mcm 4:889926e2b6a5 114 void changeDATA ( void )
mcm 4:889926e2b6a5 115 {
mcm 4:889926e2b6a5 116 myState = 1UL;
mcm 4:889926e2b6a5 117 }
mcm 1:ff93ee72c7a1 118 @endcode
mcm 1:ff93ee72c7a1 119 */
mcm 1:ff93ee72c7a1 120
mcm 1:ff93ee72c7a1 121
mcm 1:ff93ee72c7a1 122 /*!
mcm 3:082a970dca06 123 Library for the DHT11 Temperature & humidity sensor complex with a calibrated digital signal output.
mcm 1:ff93ee72c7a1 124 */
mcm 1:ff93ee72c7a1 125 class DHT11
mcm 1:ff93ee72c7a1 126 {
mcm 1:ff93ee72c7a1 127 public:
mcm 1:ff93ee72c7a1 128 /**
mcm 1:ff93ee72c7a1 129 * @brief DEVICE DELAYS.
mcm 1:ff93ee72c7a1 130 * NOTE: Values in microseconds.
mcm 1:ff93ee72c7a1 131 */
mcm 1:ff93ee72c7a1 132 typedef enum {
mcm 1:ff93ee72c7a1 133 DHT11_START_SIGNAL = 18000, /*!< Master: Start communication */
mcm 1:ff93ee72c7a1 134 DHT11_SAMPLE_DATA = 40, /*!< Sample data time */
mcm 1:ff93ee72c7a1 135 DHT11_WAIT_FOR_SENSOR_RESPONSE = 40 /*!< Master: Wait for sensor response */
mcm 1:ff93ee72c7a1 136 } DHT11_device_delays_t;
mcm 1:ff93ee72c7a1 137
mcm 1:ff93ee72c7a1 138
mcm 1:ff93ee72c7a1 139 /**
mcm 1:ff93ee72c7a1 140 * @brief DEVICE BUS STATUS.
mcm 1:ff93ee72c7a1 141 * NOTE: N/A.
mcm 1:ff93ee72c7a1 142 */
mcm 1:ff93ee72c7a1 143 typedef enum {
mcm 1:ff93ee72c7a1 144 DHT11_PIN_HIGH = 1U, /*!< Pin high */
mcm 1:ff93ee72c7a1 145 DHT11_PIN_LOW = 0U, /*!< Pin low */
mcm 1:ff93ee72c7a1 146 DHT11_PIN_UNKNOWN = 2U /*!< Pin unknown */
mcm 1:ff93ee72c7a1 147 } DHT11_device_bus_status_t;
mcm 1:ff93ee72c7a1 148
mcm 1:ff93ee72c7a1 149
mcm 1:ff93ee72c7a1 150 /**
mcm 1:ff93ee72c7a1 151 * @brief CHECKSUM STATUS.
mcm 1:ff93ee72c7a1 152 * NOTE: N/A.
mcm 1:ff93ee72c7a1 153 */
mcm 1:ff93ee72c7a1 154 typedef enum {
mcm 1:ff93ee72c7a1 155 DHT11_CHECKSUM_OK = 0U, /*!< Checksum correct */
mcm 1:ff93ee72c7a1 156 DHT11_CHECKSUM_ERROR = 1U /*!< Checksum error */
mcm 1:ff93ee72c7a1 157 } DHT11_checksum_status_t;
mcm 1:ff93ee72c7a1 158
mcm 1:ff93ee72c7a1 159
mcm 1:ff93ee72c7a1 160 /**
mcm 1:ff93ee72c7a1 161 * @brief TIMEOUT.
mcm 1:ff93ee72c7a1 162 * NOTE: This value is just an estimation, the user must check it out.
mcm 1:ff93ee72c7a1 163 */
mcm 1:ff93ee72c7a1 164 typedef enum {
mcm 1:ff93ee72c7a1 165 DHT11_TIMEOUT = 0x23232 /*!< Timeout like a counter */
mcm 1:ff93ee72c7a1 166 } DHT11_timeout_t;
mcm 1:ff93ee72c7a1 167
mcm 1:ff93ee72c7a1 168
mcm 1:ff93ee72c7a1 169
mcm 1:ff93ee72c7a1 170
mcm 1:ff93ee72c7a1 171 /**
mcm 1:ff93ee72c7a1 172 * @brief ERROR STATUS. INTERNAL CONSTANTS
mcm 1:ff93ee72c7a1 173 */
mcm 1:ff93ee72c7a1 174 typedef enum {
mcm 1:ff93ee72c7a1 175 DHT11_SUCCESS = 0U, /*!< Communication success */
mcm 1:ff93ee72c7a1 176 DHT11_FAILURE = 1U, /*!< Communication failure */
mcm 1:ff93ee72c7a1 177 DHT11_DATA_CORRUPTED = 2U, /*!< Checksum error */
mcm 1:ff93ee72c7a1 178 DHT11_BUS_TIMEOUT = 3U /*!< Bus response timeout/error */
mcm 1:ff93ee72c7a1 179 } DHT11_status_t;
mcm 1:ff93ee72c7a1 180
mcm 1:ff93ee72c7a1 181
mcm 1:ff93ee72c7a1 182
mcm 1:ff93ee72c7a1 183
mcm 1:ff93ee72c7a1 184
mcm 1:ff93ee72c7a1 185 #ifndef DHT11_VECTOR_STRUCT_H
mcm 1:ff93ee72c7a1 186 #define DHT11_VECTOR_STRUCT_H
mcm 1:ff93ee72c7a1 187 typedef struct {
mcm 1:ff93ee72c7a1 188 /* Outputs */
mcm 1:ff93ee72c7a1 189 uint8_t temperature; /*!< Temperature value */
mcm 1:ff93ee72c7a1 190 uint8_t humidity; /*!< Relative humidity value */
mcm 1:ff93ee72c7a1 191
mcm 1:ff93ee72c7a1 192 uint16_t rawTemperature; /*!< Temperature raw value */
mcm 1:ff93ee72c7a1 193 uint16_t rawHumidity; /*!< Relative humidity raw value */
mcm 1:ff93ee72c7a1 194
mcm 1:ff93ee72c7a1 195 uint8_t checksum; /*!< Checksum */
mcm 1:ff93ee72c7a1 196
mcm 1:ff93ee72c7a1 197 /* Checksum status */
mcm 1:ff93ee72c7a1 198 DHT11_checksum_status_t checksumStatus; /*!< Checksum status */
mcm 1:ff93ee72c7a1 199 } DHT11_data_t;
mcm 1:ff93ee72c7a1 200 #endif
mcm 1:ff93ee72c7a1 201
mcm 1:ff93ee72c7a1 202
mcm 1:ff93ee72c7a1 203
mcm 1:ff93ee72c7a1 204
mcm 1:ff93ee72c7a1 205
mcm 1:ff93ee72c7a1 206
mcm 1:ff93ee72c7a1 207 /**
mcm 1:ff93ee72c7a1 208 * @brief FUNCTION PROTOTYPES
mcm 1:ff93ee72c7a1 209 */
mcm 2:9fe166c478b7 210 /** Create an DHT11 object connected to the specified DHT11 device pin.
mcm 2:9fe166c478b7 211 *
mcm 2:9fe166c478b7 212 * @param dht11 Data pin
mcm 2:9fe166c478b7 213 */
mcm 2:9fe166c478b7 214 DHT11 ( PinName dht11 );
mcm 2:9fe166c478b7 215
mcm 2:9fe166c478b7 216 /** Delete DHT11 object.
mcm 2:9fe166c478b7 217 */
mcm 2:9fe166c478b7 218 ~DHT11();
mcm 4:889926e2b6a5 219
mcm 1:ff93ee72c7a1 220 /** It configures the GPIO peripheral.
mcm 1:ff93ee72c7a1 221 */
mcm 3:082a970dca06 222 DHT11_status_t DHT11_Init ( void );
mcm 1:ff93ee72c7a1 223
mcm 1:ff93ee72c7a1 224 /** It gets the raw data: Temperature, Humidity and Checksum.
mcm 1:ff93ee72c7a1 225 */
mcm 3:082a970dca06 226 DHT11_status_t DHT11_GetRawData ( DHT11_data_t* myRawData );
mcm 1:ff93ee72c7a1 227
mcm 1:ff93ee72c7a1 228 /** It gets and calculates the current data: Temperature, Humidity and Checksum.
mcm 1:ff93ee72c7a1 229 */
mcm 3:082a970dca06 230 DHT11_status_t DHT11_GetData ( DHT11_data_t* myData );
mcm 4:889926e2b6a5 231
mcm 4:889926e2b6a5 232
mcm 2:9fe166c478b7 233 private:
mcm 2:9fe166c478b7 234 DigitalInOut _dht11Pin;
mcm 1:ff93ee72c7a1 235 };
mcm 1:ff93ee72c7a1 236
mcm 1:ff93ee72c7a1 237 #endif /* DHT11_H */