DHT11 数字温湿度传感器
来自Jack's Lab
(版本间的差异)
(→参考) |
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第1行: | 第1行: | ||
== 概述 == | == 概述 == | ||
+ | |||
+ | <br><br> | ||
+ | |||
+ | == 库 == | ||
+ | |||
+ | <source lang=cpp> | ||
+ | // | ||
+ | // FILE: dht11.cpp | ||
+ | // VERSION: 0.4.1 | ||
+ | // PURPOSE: DHT11 Temperature & Humidity Sensor library for Arduino | ||
+ | // LICENSE: GPL v3 (http://www.gnu.org/licenses/gpl.html) | ||
+ | // | ||
+ | // DATASHEET: http://www.micro4you.com/files/sensor/DHT11.pdf | ||
+ | // | ||
+ | // HISTORY: | ||
+ | // George Hadjikyriacou - Original version (??) | ||
+ | // Mod by SimKard - Version 0.2 (24/11/2010) | ||
+ | // Mod by Rob Tillaart - Version 0.3 (28/03/2011) | ||
+ | // + added comments | ||
+ | // + removed all non DHT11 specific code | ||
+ | // + added references | ||
+ | // Mod by Rob Tillaart - Version 0.4 (17/03/2012) | ||
+ | // + added 1.0 support | ||
+ | // Mod by Rob Tillaart - Version 0.4.1 (19/05/2012) | ||
+ | // + added error codes | ||
+ | // | ||
+ | |||
+ | #include "dht11.h" | ||
+ | |||
+ | // Return values: | ||
+ | // DHTLIB_OK | ||
+ | // DHTLIB_ERROR_CHECKSUM | ||
+ | // DHTLIB_ERROR_TIMEOUT | ||
+ | int dht11::read(int pin) | ||
+ | { | ||
+ | // BUFFER TO RECEIVE | ||
+ | uint8_t bits[5]; | ||
+ | uint8_t cnt = 7; | ||
+ | uint8_t idx = 0; | ||
+ | |||
+ | // EMPTY BUFFER | ||
+ | for (int i=0; i< 5; i++) bits[i] = 0; | ||
+ | |||
+ | // REQUEST SAMPLE | ||
+ | pinMode(pin, OUTPUT); | ||
+ | digitalWrite(pin, LOW); | ||
+ | delay(18); | ||
+ | digitalWrite(pin, HIGH); | ||
+ | delayMicroseconds(40); | ||
+ | pinMode(pin, INPUT); | ||
+ | |||
+ | // ACKNOWLEDGE or TIMEOUT | ||
+ | unsigned int loopCnt = 10000; | ||
+ | while(digitalRead(pin) == LOW) | ||
+ | if (loopCnt-- == 0) return DHTLIB_ERROR_TIMEOUT; | ||
+ | |||
+ | loopCnt = 10000; | ||
+ | while(digitalRead(pin) == HIGH) | ||
+ | if (loopCnt-- == 0) return DHTLIB_ERROR_TIMEOUT; | ||
+ | |||
+ | // READ OUTPUT - 40 BITS => 5 BYTES or TIMEOUT | ||
+ | for (int i=0; i<40; i++) | ||
+ | { | ||
+ | loopCnt = 10000; | ||
+ | while(digitalRead(pin) == LOW) | ||
+ | if (loopCnt-- == 0) return DHTLIB_ERROR_TIMEOUT; | ||
+ | |||
+ | unsigned long t = micros(); | ||
+ | |||
+ | loopCnt = 10000; | ||
+ | while(digitalRead(pin) == HIGH) | ||
+ | if (loopCnt-- == 0) return DHTLIB_ERROR_TIMEOUT; | ||
+ | |||
+ | if ((micros() - t) > 40) bits[idx] |= (1 << cnt); | ||
+ | if (cnt == 0) // next byte? | ||
+ | { | ||
+ | cnt = 7; // restart at MSB | ||
+ | idx++; // next byte! | ||
+ | } | ||
+ | else cnt--; | ||
+ | } | ||
+ | |||
+ | // WRITE TO RIGHT VARS | ||
+ | // as bits[1] and bits[3] are allways zero they are omitted in formulas. | ||
+ | humidity = bits[0]; | ||
+ | temperature = bits[2]; | ||
+ | |||
+ | uint8_t sum = bits[0] + bits[2]; | ||
+ | |||
+ | if (bits[4] != sum) return DHTLIB_ERROR_CHECKSUM; | ||
+ | return DHTLIB_OK; | ||
+ | } | ||
+ | |||
+ | |||
+ | // | ||
+ | // FILE: dht11.h | ||
+ | // VERSION: 0.4.1 | ||
+ | // PURPOSE: DHT11 Temperature & Humidity Sensor library for Arduino | ||
+ | // LICENSE: GPL v3 (http://www.gnu.org/licenses/gpl.html) | ||
+ | // | ||
+ | // DATASHEET: http://www.micro4you.com/files/sensor/DHT11.pdf | ||
+ | // | ||
+ | // URL: http://playground.arduino.cc/Main/DHT11Lib | ||
+ | // | ||
+ | // HISTORY: | ||
+ | // George Hadjikyriacou - Original version | ||
+ | // see dht.cpp file | ||
+ | // | ||
+ | |||
+ | #ifndef dht11_h | ||
+ | #define dht11_h | ||
+ | |||
+ | #if defined(ARDUINO) && (ARDUINO >= 100) | ||
+ | #include <Arduino.h> | ||
+ | #else | ||
+ | #include <WProgram.h> | ||
+ | #endif | ||
+ | |||
+ | #define DHT11LIB_VERSION "0.4.1" | ||
+ | |||
+ | #define DHTLIB_OK 0 | ||
+ | #define DHTLIB_ERROR_CHECKSUM -1 | ||
+ | #define DHTLIB_ERROR_TIMEOUT -2 | ||
+ | |||
+ | class dht11 | ||
+ | { | ||
+ | public: | ||
+ | int read(int pin); | ||
+ | int humidity; | ||
+ | int temperature; | ||
+ | }; | ||
+ | #endif | ||
+ | </source> | ||
<br><br> | <br><br> |
2015年7月17日 (五) 17:15的版本
1 概述
2 库
// // FILE: dht11.cpp // VERSION: 0.4.1 // PURPOSE: DHT11 Temperature & Humidity Sensor library for Arduino // LICENSE: GPL v3 (http://www.gnu.org/licenses/gpl.html) // // DATASHEET: http://www.micro4you.com/files/sensor/DHT11.pdf // // HISTORY: // George Hadjikyriacou - Original version (??) // Mod by SimKard - Version 0.2 (24/11/2010) // Mod by Rob Tillaart - Version 0.3 (28/03/2011) // + added comments // + removed all non DHT11 specific code // + added references // Mod by Rob Tillaart - Version 0.4 (17/03/2012) // + added 1.0 support // Mod by Rob Tillaart - Version 0.4.1 (19/05/2012) // + added error codes // #include "dht11.h" // Return values: // DHTLIB_OK // DHTLIB_ERROR_CHECKSUM // DHTLIB_ERROR_TIMEOUT int dht11::read(int pin) { // BUFFER TO RECEIVE uint8_t bits[5]; uint8_t cnt = 7; uint8_t idx = 0; // EMPTY BUFFER for (int i=0; i< 5; i++) bits[i] = 0; // REQUEST SAMPLE pinMode(pin, OUTPUT); digitalWrite(pin, LOW); delay(18); digitalWrite(pin, HIGH); delayMicroseconds(40); pinMode(pin, INPUT); // ACKNOWLEDGE or TIMEOUT unsigned int loopCnt = 10000; while(digitalRead(pin) == LOW) if (loopCnt-- == 0) return DHTLIB_ERROR_TIMEOUT; loopCnt = 10000; while(digitalRead(pin) == HIGH) if (loopCnt-- == 0) return DHTLIB_ERROR_TIMEOUT; // READ OUTPUT - 40 BITS => 5 BYTES or TIMEOUT for (int i=0; i<40; i++) { loopCnt = 10000; while(digitalRead(pin) == LOW) if (loopCnt-- == 0) return DHTLIB_ERROR_TIMEOUT; unsigned long t = micros(); loopCnt = 10000; while(digitalRead(pin) == HIGH) if (loopCnt-- == 0) return DHTLIB_ERROR_TIMEOUT; if ((micros() - t) > 40) bits[idx] |= (1 << cnt); if (cnt == 0) // next byte? { cnt = 7; // restart at MSB idx++; // next byte! } else cnt--; } // WRITE TO RIGHT VARS // as bits[1] and bits[3] are allways zero they are omitted in formulas. humidity = bits[0]; temperature = bits[2]; uint8_t sum = bits[0] + bits[2]; if (bits[4] != sum) return DHTLIB_ERROR_CHECKSUM; return DHTLIB_OK; } // // FILE: dht11.h // VERSION: 0.4.1 // PURPOSE: DHT11 Temperature & Humidity Sensor library for Arduino // LICENSE: GPL v3 (http://www.gnu.org/licenses/gpl.html) // // DATASHEET: http://www.micro4you.com/files/sensor/DHT11.pdf // // URL: http://playground.arduino.cc/Main/DHT11Lib // // HISTORY: // George Hadjikyriacou - Original version // see dht.cpp file // #ifndef dht11_h #define dht11_h #if defined(ARDUINO) && (ARDUINO >= 100) #include <Arduino.h> #else #include <WProgram.h> #endif #define DHT11LIB_VERSION "0.4.1" #define DHTLIB_OK 0 #define DHTLIB_ERROR_CHECKSUM -1 #define DHTLIB_ERROR_TIMEOUT -2 class dht11 { public: int read(int pin); int humidity; int temperature; }; #endif
3 参考
- http://playground.arduino.cc/Main/DHT11Lib
- http://www.micro4you.com/files/sensor/DHT11.pdf
- http://playground.arduino.cc/Main/DHTLib