SDHT/SDHT.h at master · offcircuit/SDHT · GitHub

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#ifndef SDHT_H
#define SDHT_H

#define DHT11 0
#define DHT12 1
#define DHT21 2
#define DHT22 3

#define SDHT_CYCLES microsecondsToClockCycles(200)

class SDHT {
  private:
    uint16_t _humidity = 0;
    int16_t _celsius = 0;

  public:
    const uint16_t &humidity = _humidity;
    const int16_t &celsius = _celsius;

    explicit SDHT() {};

    bool read(uint8_t model, uint8_t pin) {
      uint8_t data[5] = {0, 0, 0, 0, 0};

      pinMode(pin, OUTPUT);
      digitalWrite(pin, LOW);
      pulseIn(pin, HIGH, (model < DHT21) ? 20000 : 1000);
      digitalWrite(pin, HIGH);
      pinMode(pin, INPUT);

      if (!pulseIn(pin, HIGH, 300)) return false;
      for (uint8_t i = 0; i < 40; i++) data[i / 8] += data[i / 8] + (pulse(pin, LOW) > pulse(pin, HIGH));

      if (data[4] != uint8_t(data[0] + data[1] + data[2] + data[3])) return false;

      switch (model) {
        case DHT11:
          _humidity = (data[0] * 10) + data[1];
          _celsius = (data[2] * 10) + data[3];
          break;

        case DHT12:
          _humidity = (data[0] * 10) + data[1];
          _celsius = ((data[2] * 10) + (data[3] & 0x7F)) * ((data[3] & 0x80) ? -1 : 1);
          #ifndef SDHT_H
#define SDHT_H

#define DHT11 0
#define DHT12 1
#define DHT21 2
#define DHT22 3

#define SDHT_CYCLES microsecondsToClockCycles(200)

class SDHT {
private:
  uint16_t _humidity = 0;
  int16_t _celsius = 0;

public:
  const uint16_t &humidity = _humidity;
  const int16_t &celsius = _celsius;

  explicit SDHT(){};

  bool read(uint8_t model, uint8_t pin) {
    uint8_t data[5] = { 0, 0, 0, 0, 0 };

    pinMode(pin, OUTPUT);
    digitalWrite(pin, LOW);
    pulseIn(pin, HIGH, (model < DHT21) ? 20000 : 1000);
    digitalWrite(pin, HIGH);
    pinMode(pin, INPUT);

    if (!pulseIn(pin, HIGH, 300)) return false;
    for (uint8_t i = 0; i < 40; i++) data[i / 8] += data[i / 8] + (pulse(pin, LOW) > pulse(pin, HIGH));

    if (data[4] != uint8_t(data[0] + data[1] + data[2] + data[3])) return false;

    switch (model) {
      case DHT11:
        _humidity = (data[0] * 10) + data[1];
        _celsius = (data[2] * 10) + data[3];
        break;

      case DHT12:
        _humidity = (data[0] * 10) + data[1];
        _celsius = ((data[2] * 10) + (data[3] & 0x7F)) * ((data[3] & 0x80) ? -1 : 1);
        break;

      case DHT21:
      case DHT22:
        _humidity = (uint16_t(data[0] << 8) | data[1]);
        _celsius = (uint16_t((data[2] & 0x7F) << 8) | data[3]) * ((data[2] & 0x80) ? -1 : 1);
        break;

      default: return false;
    }
    return true;
  }

  uint16_t pulse(uint8_t pin, int state) {
    uint16_t cycle = SDHT_CYCLES;
    while ((digitalRead(pin) == state) && cycle--)
      ;
    return cycle;
  }
};

#endif
        case DHT21:
        case DHT22:
          _humidity = (uint16_t(data[0] << 8) | data[1]);
          _celsius = (uint16_t((data[2] & 0x7F) << 8) | data[3]) * ((data[2] & 0x80) ? -1 : 1);

        default: return false;
      }
      return true;
    }

    uint16_t pulse(uint8_t pin, int state) {
      uint16_t cycle = SDHT_CYCLES;
      while ((digitalRead(pin) == state) && cycle--);
      return cycle;
    }
};

#endif