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arduino dht11库文件arduino-DHT-master下载

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ID:516597发表于 2019-4-19 18:04|只看该作者|只看大图回帖奖励


单片机源程序如下:
  1. #include "DHT.h"

  3. void DHT::setup(uint8_t pin, DHT_MODEL_t model)
  4. {
  5.   DHT::pin = pin;
  6.   DHT::model = model;
  7.   DHT::resetTimer(); // Make sure we do read the sensor in the next readSensor()

  9.   if ( model == AUTO_DETECT) {
  10.    DHT::model = DHT22;
  11.    readSensor();
  12.    if ( error == ERROR_TIMEOUT ) {
  13.      DHT::model = DHT11;
  14.      // Warning: in case we auto detect a DHT11, you should wait at least 1000 msec
  15.      // before your first read request. Otherwise you will get a time out error.
  16.    }
  17.   }
  18. }

  20. void DHT::resetTimer()
  21. {
  22.   DHT::lastReadTime = millis() - 3000;
  23. }

  25. float DHT::getHumidity()
  26. {
  27.   readSensor();
  28.   return humidity;
  29. }

  31. float DHT::getTemperature()
  32. {
  33.   readSensor();
  34.   return temperature;
  35. }

  37. #ifndef OPTIMIZE_SRAM_SIZE

  39. const char* DHT::getStatusString()
  40. {
  41.   switch ( error ) {
  42.    case DHT::ERROR_TIMEOUT:
  43.      return "TIMEOUT";

  45.    case DHT::ERROR_CHECKSUM:
  46.      return "CHECKSUM";

  48.    default:
  49.      return "OK";
  50.   }
  51. }

  53. #else

  55. // At the expense of 26 bytes of extra PROGMEM, we save 11 bytes of
  56. // SRAM by using the following method:

  58. prog_char P_OK[]     PROGMEM = "OK";
  59. prog_char P_TIMEOUT[]  PROGMEM = "TIMEOUT";
  60. prog_char P_CHECKSUM[] PROGMEM = "CHECKSUM";

  62. const char *DHT::getStatusString() {
  63.   prog_char *c;
  64.   switch ( error ) {
  65.    case DHT::ERROR_CHECKSUM:
  66.      c = P_CHECKSUM; break;

  68.    case DHT::ERROR_TIMEOUT:
  69.      c = P_TIMEOUT; break;

  71.    default:
  72.      c = P_OK; break;
  73.   }

  75.   static char buffer[9];
  76.   strcpy_P(buffer, c);

  78.   return buffer;
  79. }

  81. #endif

  83. void DHT::readSensor()
  84. {
  85.   // Make sure we don't poll the sensor too often
  86.   // - Max sample rate DHT11 is 1 Hz   (duty cicle 1000 ms)
  87.   // - Max sample rate DHT22 is 0.5 Hz (duty cicle 2000 ms)
  88.   unsigned long startTime = millis();
  89.   if ( (unsigned long)(startTime - lastReadTime)< (model == DHT11 ? 999L : 1999L) ) {
  90.    return;
  91.   }
  92.   lastReadTime = startTime;

  94.   temperature = NAN;
  95.   humidity = NAN;

  97.   // Request sample

  99.   digitalWrite(pin, LOW); // Send start signal
  100.   pinMode(pin, OUTPUT);
  101.   if ( model == DHT11 ) {
  102.    delay(18);
  103.   }
  104.   else {
  105.    // This will fail for a DHT11 - that's how we can detect such a device
  106.    delayMicroseconds(800);
  107.   }

  109.   pinMode(pin, INPUT);
  110.   digitalWrite(pin, HIGH); // Switch bus to receive data

  112.   // We're going to read 83 edges:
  113.   // - First a FALLING, RISING, and FALLING edge for the start bit
  114.   // - Then 40 bits: RISING and then a FALLING edge per bit
  115.   // To keep our code simple, we accept any HIGH or LOW reading if it's max 85 usecs long

  117.   uint16_t rawHumidity = 0;
  118.   uint16_t rawTemperature = 0;
  119.   uint16_t data = 0;

  121.   for ( int8_t i = -3 ; i< 2 * 40; i++ ) {
  122.    byte age;
  123.    startTime = micros();

  125.    do {
  126.      age = (unsigned long)(micros() - startTime);
  127.      if ( age > 90 ) {
  128.        error = ERROR_TIMEOUT;
  129.        return;
  130.      }
  131.    }
  132.    while ( digitalRead(pin) == (i& 1) ? HIGH : LOW );

  134.    if ( i >= 0&& (i& 1) ) {
  135.      // Now we are being fed our 40 bits
  136.      data<< = 1;

  138.      // A zero max 30 usecs, a one at least 68 usecs.
  139.      if ( age > 30 ) {
  140.        data |= 1; // we got a one
  141.      }
  142.    }

  144.    switch ( i ) {
  145.      case 31:
  146.        rawHumidity = data;
  147.        break;
  148.      case 63:
  149.        rawTemperature = data;
  150.        data = 0;
  151.        break;
  152.    }
  153.   }

  155.   // Verify checksum

  157.   if ( (byte)(((byte)rawHumidity) + (rawHumidity >> 8) + ((byte)rawTemperature) + (rawTemperature >> 8)) != data ) {
  158.    error = ERROR_CHECKSUM;
  159.    return;
  160.   }

  162.   // Store readings

  164.   if ( model == DHT11 ) {
  165.    humidity = rawHumidity >> 8;
  166.    temperature = rawTemperature >> 8;
  167.   }
  168.   else {
  169.    humidity = rawHumidity * 0.1;

  171.    if ( rawTemperature& 0x8000 ) {
  172.      rawTemperature = -(int16_t)(rawTemperature& 0x7FFF);
  173.    }
  174.    temperature = ((int16_t)rawTemperature) * 0.1;
  175.   }

  177.   error = ERROR_NONE;
  178. }

复制代码

所有资料51hei提供下载:
arduino-DHT-master (1).zip(42.91 KB, 下载次数: 165)


沙发
ID:530524发表于 2019-5-8 13:00|只看该作者
这个很有用
板凳
ID:13396发表于 2020-12-25 19:57|只看该作者
谢谢分享，这个有用。

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