mirror of
https://github.com/RobTillaart/Arduino.git
synced 2024-10-03 18:09:02 -04:00
435 lines
9.3 KiB
C++
435 lines
9.3 KiB
C++
//
|
|
// FILE: dhtnew.cpp
|
|
// AUTHOR: Rob Tillaart
|
|
// VERSION: 0.4.20
|
|
// PURPOSE: DHT Temperature & Humidity Sensor library for Arduino
|
|
// URL: https://github.com/RobTillaart/DHTNEW
|
|
//
|
|
// HISTORY: see changelog.md
|
|
|
|
|
|
#include "dhtnew.h"
|
|
#include <stdint.h>
|
|
|
|
|
|
// these defines are not for user to adjust (microseconds)
|
|
#define DHTLIB_DHT11_WAKEUP (18 * 1100UL)
|
|
#define DHTLIB_DHT_WAKEUP (1 * 1100UL)
|
|
// experimental 0.4.14
|
|
#define DHTLIB_SI7021_WAKEUP (500)
|
|
|
|
|
|
// READ_DELAY for blocking read
|
|
// datasheet: DHT11 = 1000 and DHT22 = 2000
|
|
// use setReadDelay() to overrule (at own risk)
|
|
// as individual sensors can be read faster.
|
|
// see example DHTnew_setReadDelay.ino
|
|
#define DHTLIB_DHT11_READ_DELAY 1000
|
|
#define DHTLIB_DHT22_READ_DELAY 2000
|
|
|
|
|
|
/////////////////////////////////////////////////////
|
|
//
|
|
// PUBLIC
|
|
//
|
|
DHTNEW::DHTNEW(uint8_t pin)
|
|
{
|
|
_dataPin = pin;
|
|
reset();
|
|
};
|
|
|
|
|
|
void DHTNEW::reset()
|
|
{
|
|
// Data-bus's free status is high voltage level.
|
|
pinMode(_dataPin, OUTPUT);
|
|
digitalWrite(_dataPin, HIGH);
|
|
|
|
_wakeupDelay = 0;
|
|
_type = 0;
|
|
_humOffset = 0.0;
|
|
_tempOffset = 0.0;
|
|
_humidity = 0.0;
|
|
_temperature = 0.0;
|
|
_lastRead = 0;
|
|
_disableIRQ = true;
|
|
_waitForRead = false;
|
|
_suppressError = false;
|
|
_readDelay = 0;
|
|
#if defined(__AVR__)
|
|
_disableIRQ = false;
|
|
#endif
|
|
// #if defined(ARDUINO_SAMD_MKRWIFI1010) // fix for issue #67
|
|
// _disableIRQ = false;
|
|
// #endif
|
|
}
|
|
|
|
|
|
uint8_t DHTNEW::getType()
|
|
{
|
|
if (_type == 0) read();
|
|
return _type;
|
|
}
|
|
|
|
|
|
void DHTNEW::setType(uint8_t type)
|
|
{
|
|
// default type == 0 or unsupported
|
|
_type = 0;
|
|
_wakeupDelay = DHTLIB_DHT11_WAKEUP;
|
|
|
|
if ((type == 22) || (type == 23))
|
|
{
|
|
_type = type;
|
|
_wakeupDelay = DHTLIB_DHT_WAKEUP;
|
|
}
|
|
else if (type == 11)
|
|
{
|
|
_type = type;
|
|
_wakeupDelay = DHTLIB_DHT11_WAKEUP;
|
|
}
|
|
// experimental 0.4.14
|
|
else if (type == 70)
|
|
{
|
|
_type = type;
|
|
_wakeupDelay = DHTLIB_SI7021_WAKEUP;
|
|
}
|
|
}
|
|
|
|
|
|
// return values:
|
|
// DHTLIB_OK
|
|
// DHTLIB_WAITING_FOR_READ
|
|
// DHTLIB_ERROR_CHECKSUM
|
|
// DHTLIB_ERROR_BIT_SHIFT
|
|
// DHTLIB_ERROR_SENSOR_NOT_READY
|
|
// DHTLIB_ERROR_TIMEOUT_A
|
|
// DHTLIB_ERROR_TIMEOUT_B
|
|
// DHTLIB_ERROR_TIMEOUT_C
|
|
// DHTLIB_ERROR_TIMEOUT_D
|
|
int DHTNEW::read()
|
|
{
|
|
if (_readDelay == 0)
|
|
{
|
|
_readDelay = DHTLIB_DHT22_READ_DELAY;
|
|
if (_type == 11) _readDelay = DHTLIB_DHT11_READ_DELAY;
|
|
}
|
|
if (_type != 0)
|
|
{
|
|
while (millis() - _lastRead < _readDelay)
|
|
{
|
|
if (!_waitForRead) return DHTLIB_WAITING_FOR_READ;
|
|
yield();
|
|
}
|
|
return _read();
|
|
}
|
|
|
|
// AUTODETECT
|
|
// make sure sensor had time to wake up.
|
|
while (millis() < 1000);
|
|
|
|
// NOTE: cannot differentiate between type 23 and 22
|
|
_type = 22;
|
|
_wakeupDelay = DHTLIB_DHT_WAKEUP;
|
|
int rv = _read();
|
|
if (rv == DHTLIB_OK) return rv;
|
|
|
|
_type = 11;
|
|
_wakeupDelay = DHTLIB_DHT11_WAKEUP;
|
|
rv = _read();
|
|
if (rv == DHTLIB_OK) return rv;
|
|
|
|
// experimental 0.4.14
|
|
_type = 70;
|
|
_wakeupDelay = DHTLIB_SI7021_WAKEUP;
|
|
rv = _read();
|
|
if (rv == DHTLIB_OK) return rv;
|
|
|
|
_type = 0; // retry next time
|
|
return rv;
|
|
}
|
|
|
|
|
|
// return values:
|
|
// DHTLIB_OK
|
|
// DHTLIB_ERROR_CHECKSUM
|
|
// DHTLIB_ERROR_BIT_SHIFT
|
|
// DHTLIB_ERROR_SENSOR_NOT_READY
|
|
// DHTLIB_ERROR_TIMEOUT_A
|
|
// DHTLIB_ERROR_TIMEOUT_B
|
|
// DHTLIB_ERROR_TIMEOUT_C
|
|
// DHTLIB_ERROR_TIMEOUT_D
|
|
int DHTNEW::_read()
|
|
{
|
|
// READ VALUES
|
|
int rv = _readSensor();
|
|
|
|
// enable interrupts again
|
|
#if defined(ESP32)
|
|
portENABLE_INTERRUPTS();
|
|
#else
|
|
interrupts();
|
|
#endif
|
|
// Data-bus's free status is high voltage level.
|
|
pinMode(_dataPin, OUTPUT);
|
|
digitalWrite(_dataPin, HIGH);
|
|
_lastRead = millis();
|
|
|
|
if (rv != DHTLIB_OK)
|
|
{
|
|
if (_suppressError == false)
|
|
{
|
|
_humidity = DHTLIB_INVALID_VALUE;
|
|
_temperature = DHTLIB_INVALID_VALUE;
|
|
}
|
|
return rv; // propagate error value
|
|
}
|
|
|
|
if (_type == 11) // DHT11, DH12, compatible
|
|
{
|
|
_humidity = _bits[0] + _bits[1] * 0.1;
|
|
_temperature = _bits[2] + _bits[3] * 0.1;
|
|
}
|
|
else // DHT22, DHT33, DHT44, compatible + Si7021
|
|
{
|
|
_humidity = (_bits[0] * 256 + _bits[1]) * 0.1;
|
|
int16_t t = ((_bits[2] & 0x7F) * 256 + _bits[3]);
|
|
if (t == 0)
|
|
{
|
|
_temperature = 0.0; // prevent -0.0;
|
|
}
|
|
else
|
|
{
|
|
_temperature = t * 0.1;
|
|
if((_bits[2] & 0x80) == 0x80 )
|
|
{
|
|
_temperature = -_temperature;
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
// HEXDUMP DEBUG
|
|
/*
|
|
Serial.println();
|
|
// CHECKSUM
|
|
if (_bits[4] < 0x10) Serial.print(0);
|
|
Serial.print(_bits[4], HEX);
|
|
Serial.print(" ");
|
|
// TEMPERATURE
|
|
if (_bits[2] < 0x10) Serial.print(0);
|
|
Serial.print(_bits[2], HEX);
|
|
if (_bits[3] < 0x10) Serial.print(0);
|
|
Serial.print(_bits[3], HEX);
|
|
Serial.print(" ");
|
|
Serial.print(_temperature, 1);
|
|
Serial.print(" ");
|
|
// HUMIDITY
|
|
if (_bits[0] < 0x10) Serial.print(0);
|
|
Serial.print(_bits[0], HEX);
|
|
if (_bits[1] < 0x10) Serial.print(0);
|
|
Serial.print(_bits[1], HEX);
|
|
Serial.print(" ");
|
|
Serial.print(_humidity, 1);
|
|
*/
|
|
|
|
// TEST OUT OF RANGE
|
|
#ifdef DHTLIB_VALUE_OUT_OF_RANGE
|
|
if (_humidity > 100)
|
|
{
|
|
return DHTLIB_HUMIDITY_OUT_OF_RANGE;
|
|
}
|
|
if ((_temperature < -40) || (_temperature > 80))
|
|
{
|
|
return DHTLIB_TEMPERATURE_OUT_OF_RANGE;
|
|
}
|
|
#endif
|
|
|
|
if (_humOffset != 0.0)
|
|
{
|
|
_humidity += _humOffset;
|
|
if (_humidity > 100) _humidity = 100;
|
|
else if (_humidity < 0) _humidity = 0;
|
|
}
|
|
if (_tempOffset != 0.0)
|
|
{
|
|
_temperature += _tempOffset;
|
|
}
|
|
|
|
// TEST CHECKSUM
|
|
uint8_t sum = _bits[0] + _bits[1] + _bits[2] + _bits[3];
|
|
if (_bits[4] != sum)
|
|
{
|
|
return DHTLIB_ERROR_CHECKSUM;
|
|
}
|
|
|
|
return DHTLIB_OK;
|
|
}
|
|
|
|
|
|
void DHTNEW::powerUp()
|
|
{
|
|
digitalWrite(_dataPin, HIGH);
|
|
// do a dummy read to synchronise the sensor
|
|
read();
|
|
};
|
|
|
|
|
|
void DHTNEW::powerDown()
|
|
{
|
|
digitalWrite(_dataPin, LOW);
|
|
}
|
|
|
|
|
|
/////////////////////////////////////////////////////
|
|
//
|
|
// PRIVATE
|
|
//
|
|
|
|
// return values:
|
|
// DHTLIB_OK
|
|
// DHTLIB_ERROR_CHECKSUM
|
|
// DHTLIB_ERROR_BIT_SHIFT
|
|
// DHTLIB_ERROR_SENSOR_NOT_READY
|
|
// DHTLIB_ERROR_TIMEOUT_A
|
|
// DHTLIB_ERROR_TIMEOUT_B
|
|
// DHTLIB_ERROR_TIMEOUT_C
|
|
// DHTLIB_ERROR_TIMEOUT_D
|
|
int DHTNEW::_readSensor()
|
|
{
|
|
// INIT BUFFERVAR TO RECEIVE DATA
|
|
uint8_t mask = 0x80;
|
|
uint8_t idx = 0;
|
|
|
|
// EMPTY BUFFER
|
|
for (uint8_t i = 0; i < 5; i++)
|
|
{
|
|
_bits[i] = 0;
|
|
}
|
|
|
|
// REQUEST SAMPLE - SEND WAKEUP TO SENSOR
|
|
pinMode(_dataPin, OUTPUT);
|
|
digitalWrite(_dataPin, LOW);
|
|
|
|
// HANDLE SI7021 separately (see #79)
|
|
if (_type == 70)
|
|
{
|
|
delayMicroseconds(DHTLIB_SI7021_WAKEUP); // hardcoded for now
|
|
}
|
|
else
|
|
{
|
|
// WAKE UP - add 10% extra for timing inaccuracies in sensor.
|
|
uint32_t startWakeup = micros();
|
|
do
|
|
{
|
|
// HANDLE PENDING IRQ
|
|
yield();
|
|
// 180 gives good wakeup delay on UNO for DHT22 / DHT11 (issue #72)
|
|
delayMicroseconds(180UL);
|
|
}
|
|
while((micros() - startWakeup) < _wakeupDelay);
|
|
}
|
|
|
|
// HOST GIVES CONTROL TO SENSOR
|
|
digitalWrite(_dataPin, HIGH);
|
|
delayMicroseconds(2);
|
|
pinMode(_dataPin, INPUT_PULLUP);
|
|
|
|
// DISABLE INTERRUPTS when clock in the bits
|
|
if (_disableIRQ)
|
|
{
|
|
#if defined(ESP32)
|
|
portDISABLE_INTERRUPTS();
|
|
#else
|
|
noInterrupts();
|
|
#endif
|
|
}
|
|
|
|
// DHT22 (and others including Si7021)
|
|
// SENSOR PULLS LOW after 20-40 us => if stays HIGH ==> device not ready
|
|
// timeout is 20 us less due to delay() above
|
|
// DHT11
|
|
// SENSOR PULLS LOW after 6000-10000 us
|
|
uint32_t WAITFORSENSOR = 50;
|
|
if (_type == 11) WAITFORSENSOR = 15000UL;
|
|
if (_waitFor(LOW, WAITFORSENSOR)) return DHTLIB_ERROR_SENSOR_NOT_READY;
|
|
|
|
// SENSOR STAYS LOW for ~80 us => or TIMEOUT
|
|
if (_waitFor(HIGH, 90)) return DHTLIB_ERROR_TIMEOUT_A;
|
|
|
|
// SENSOR STAYS HIGH for ~80 us => or TIMEOUT
|
|
if (_waitFor(LOW, 90)) return DHTLIB_ERROR_TIMEOUT_B;
|
|
|
|
// SENSOR HAS NOW SEND ACKNOWLEDGE ON WAKEUP
|
|
// NOW IT SENDS THE BITS
|
|
|
|
// READ THE OUTPUT - 40 BITS => 5 BYTES
|
|
for (uint8_t i = 40; i != 0; i--)
|
|
{
|
|
// EACH BIT START WITH ~50 us LOW
|
|
if (_waitFor(HIGH, 90))
|
|
{
|
|
// Most critical timeout
|
|
// Serial.print("IC: ");
|
|
// Serial.println(i);
|
|
return DHTLIB_ERROR_TIMEOUT_C;
|
|
}
|
|
|
|
// DURATION OF HIGH DETERMINES 0 or 1
|
|
// 26-28 us ==> 0
|
|
// 70 us ==> 1
|
|
uint32_t t = micros();
|
|
if (_waitFor(LOW, 90))
|
|
{
|
|
// Serial.print("ID: ");
|
|
// Serial.println(i);
|
|
return DHTLIB_ERROR_TIMEOUT_D;
|
|
}
|
|
if ((micros() - t) > DHTLIB_BIT_THRESHOLD)
|
|
{
|
|
_bits[idx] |= mask;
|
|
}
|
|
|
|
// PREPARE FOR NEXT BIT
|
|
mask >>= 1;
|
|
if (mask == 0) // next byte?
|
|
{
|
|
mask = 0x80;
|
|
idx++;
|
|
}
|
|
}
|
|
// After 40 bits the sensor pulls the line LOW for 50 us
|
|
// No functional need to wait for this one
|
|
// if (_waitFor(HIGH, 60)) return DHTLIB_ERROR_TIMEOUT_E;
|
|
|
|
// CATCH RIGHTSHIFT BUG ESP (only 1 single bit shift)
|
|
// humidity is maximum 1000 = 0x03E8 for DHT22 and 0x6400 for DHT11
|
|
// so most significant bit may never be set.
|
|
if (_bits[0] & 0x80) return DHTLIB_ERROR_BIT_SHIFT;
|
|
|
|
return DHTLIB_OK;
|
|
}
|
|
|
|
|
|
// returns true if timeout has passed.
|
|
// returns false if timeout is not reached and state is seen.
|
|
bool DHTNEW::_waitFor(uint8_t state, uint32_t timeout)
|
|
{
|
|
uint32_t start = micros();
|
|
uint8_t count = 2;
|
|
while ((micros() - start) < timeout)
|
|
{
|
|
// delayMicroseconds(1); // less # reads ==> minimizes # glitch reads
|
|
if (digitalRead(_dataPin) == state)
|
|
{
|
|
count--;
|
|
if (count == 0) return false; // requested state seen count times
|
|
}
|
|
}
|
|
return true;
|
|
}
|
|
|
|
|
|
// -- END OF FILE --
|
|
|