mirror of
https://github.com/RobTillaart/Arduino.git
synced 2024-09-19 16:46:11 -04:00
428 lines
9.3 KiB
C++
428 lines
9.3 KiB
C++
//
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// FILE: dhtnew.cpp
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// AUTHOR: Rob Tillaart
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// VERSION: 0.4.19
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// PURPOSE: DHT Temperature & Humidity Sensor library for Arduino
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// URL: https://github.com/RobTillaart/DHTNEW
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//
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// HISTORY: see changelog.md
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#include "dhtnew.h"
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#include <stdint.h>
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// these defines are not for user to adjust (microseconds)
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#define DHTLIB_DHT11_WAKEUP (18 * 1100UL)
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#define DHTLIB_DHT_WAKEUP (1 * 1100UL)
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// experimental 0.4.14
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#define DHTLIB_SI7021_WAKEUP (500)
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// READ_DELAY for blocking read
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// datasheet: DHT11 = 1000 and DHT22 = 2000
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// use setReadDelay() to overrule (at own risk)
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// as individual sensors can be read faster.
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// see example DHTnew_setReadDelay.ino
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#define DHTLIB_DHT11_READ_DELAY 1000
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#define DHTLIB_DHT22_READ_DELAY 2000
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/////////////////////////////////////////////////////
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//
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// PUBLIC
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//
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DHTNEW::DHTNEW(uint8_t pin)
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{
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_dataPin = pin;
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reset();
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};
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void DHTNEW::reset()
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{
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// Data-bus's free status is high voltage level.
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pinMode(_dataPin, OUTPUT);
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digitalWrite(_dataPin, HIGH);
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_wakeupDelay = 0;
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_type = 0;
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_humOffset = (float)0.0;
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_tempOffset = (float)0.0;
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_humidity = (float)0.0;
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_temperature = (float)0.0;
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_lastRead = 0;
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_disableIRQ = true;
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_waitForRead = false;
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_suppressError = false;
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_readDelay = 0;
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#if defined(__AVR__)
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_disableIRQ = false;
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#endif
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// #if defined(ARDUINO_SAMD_MKRWIFI1010) // fix for issue #67
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// _disableIRQ = false;
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// #endif
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}
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uint8_t DHTNEW::getType()
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{
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if (_type == 0) read();
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return _type;
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}
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void DHTNEW::setType(uint8_t type)
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{
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if ((type == 0) || (type == 11))
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{
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_type = type;
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_wakeupDelay = DHTLIB_DHT11_WAKEUP;
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}
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if ((type == 22) || (type == 23))
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{
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_type = type;
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_wakeupDelay = DHTLIB_DHT_WAKEUP;
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}
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// experimental 0.4.14
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if (type == 70)
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{
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_type = type;
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_wakeupDelay = DHTLIB_SI7021_WAKEUP;
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}
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}
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// return values:
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// DHTLIB_OK
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// DHTLIB_WAITING_FOR_READ
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// DHTLIB_ERROR_CHECKSUM
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// DHTLIB_ERROR_BIT_SHIFT
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// DHTLIB_ERROR_SENSOR_NOT_READY
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// DHTLIB_ERROR_TIMEOUT_A
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// DHTLIB_ERROR_TIMEOUT_B
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// DHTLIB_ERROR_TIMEOUT_C
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// DHTLIB_ERROR_TIMEOUT_D
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int DHTNEW::read()
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{
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if (_readDelay == 0)
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{
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_readDelay = DHTLIB_DHT22_READ_DELAY;
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if (_type == 11) _readDelay = DHTLIB_DHT11_READ_DELAY;
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}
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if (_type != 0)
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{
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while (millis() - _lastRead < _readDelay)
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{
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if (!_waitForRead) return DHTLIB_WAITING_FOR_READ;
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yield();
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}
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return _read();
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}
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// AUTODETECT
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// make sure sensor had time to wake up.
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while (millis() < 1000);
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// NOTE: cannot differentiate between type 23 and 22
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_type = 22;
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_wakeupDelay = DHTLIB_DHT_WAKEUP;
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int rv = _read();
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if (rv == DHTLIB_OK) return rv;
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_type = 11;
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_wakeupDelay = DHTLIB_DHT11_WAKEUP;
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rv = _read();
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if (rv == DHTLIB_OK) return rv;
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// experimental 0.4.14
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_type = 70;
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_wakeupDelay = DHTLIB_SI7021_WAKEUP;
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rv = _read();
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if (rv == DHTLIB_OK) return rv;
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_type = 0; // retry next time
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return rv;
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}
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// return values:
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// DHTLIB_OK
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// DHTLIB_ERROR_CHECKSUM
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// DHTLIB_ERROR_BIT_SHIFT
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// DHTLIB_ERROR_SENSOR_NOT_READY
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// DHTLIB_ERROR_TIMEOUT_A
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// DHTLIB_ERROR_TIMEOUT_B
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// DHTLIB_ERROR_TIMEOUT_C
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// DHTLIB_ERROR_TIMEOUT_D
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int DHTNEW::_read()
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{
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// READ VALUES
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int rv = _readSensor();
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// enable interrupts again
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#if defined(ESP32)
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portENABLE_INTERRUPTS();
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#else
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interrupts();
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#endif
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// Data-bus's free status is high voltage level.
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pinMode(_dataPin, OUTPUT);
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digitalWrite(_dataPin, HIGH);
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_lastRead = millis();
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if (rv != DHTLIB_OK)
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{
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if (_suppressError == false)
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{
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_humidity = DHTLIB_INVALID_VALUE;
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_temperature = DHTLIB_INVALID_VALUE;
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}
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return rv; // propagate error value
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}
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if (_type == 11) // DHT11, DH12, compatible
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{
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_humidity = _bits[0] + _bits[1] * 0.1;
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_temperature = _bits[2] + _bits[3] * 0.1;
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}
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else // DHT22, DHT33, DHT44, compatible + Si7021
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{
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_humidity = (_bits[0] * 256 + _bits[1]) * 0.1;
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int16_t t = ((_bits[2] & 0x7F) * 256 + _bits[3]);
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if (t == 0)
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{
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_temperature = (float)0.0; // prevent -0.0;
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}
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else
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{
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_temperature = t * 0.1;
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if((_bits[2] & 0x80) == 0x80 )
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{
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_temperature = -_temperature;
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}
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}
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}
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// HEXDUMP DEBUG
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/*
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Serial.println();
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// CHECKSUM
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if (_bits[4] < 0x10) Serial.print(0);
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Serial.print(_bits[4], HEX);
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Serial.print(" ");
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// TEMPERATURE
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if (_bits[2] < 0x10) Serial.print(0);
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Serial.print(_bits[2], HEX);
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if (_bits[3] < 0x10) Serial.print(0);
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Serial.print(_bits[3], HEX);
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Serial.print(" ");
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Serial.print(_temperature, 1);
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Serial.print(" ");
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// HUMIDITY
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if (_bits[0] < 0x10) Serial.print(0);
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Serial.print(_bits[0], HEX);
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if (_bits[1] < 0x10) Serial.print(0);
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Serial.print(_bits[1], HEX);
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Serial.print(" ");
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Serial.print(_humidity, 1);
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*/
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// TEST OUT OF RANGE
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#ifdef DHTLIB_VALUE_OUT_OF_RANGE
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if (_humidity > 100)
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{
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return DHTLIB_HUMIDITY_OUT_OF_RANGE;
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}
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if ((_temperature < -40) || (_temperature > 80))
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{
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return DHTLIB_TEMPERATURE_OUT_OF_RANGE;
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}
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#endif
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if (_humOffset != (float)0.0)
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{
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_humidity += _humOffset;
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if (_humidity < 0) _humidity = 0;
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if (_humidity > 100) _humidity = 100;
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}
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if (_tempOffset != (float)0.0)
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{
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_temperature += _tempOffset;
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}
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// TEST CHECKSUM
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uint8_t sum = _bits[0] + _bits[1] + _bits[2] + _bits[3];
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if (_bits[4] != sum)
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{
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return DHTLIB_ERROR_CHECKSUM;
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}
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return DHTLIB_OK;
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}
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void DHTNEW::powerUp()
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{
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digitalWrite(_dataPin, HIGH);
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// do a dummy read to sync the sensor
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read();
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};
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void DHTNEW::powerDown()
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{
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digitalWrite(_dataPin, LOW);
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}
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/////////////////////////////////////////////////////
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//
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// PRIVATE
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//
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// return values:
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// DHTLIB_OK
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// DHTLIB_ERROR_CHECKSUM
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// DHTLIB_ERROR_BIT_SHIFT
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// DHTLIB_ERROR_SENSOR_NOT_READY
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// DHTLIB_ERROR_TIMEOUT_A
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// DHTLIB_ERROR_TIMEOUT_B
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// DHTLIB_ERROR_TIMEOUT_C
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// DHTLIB_ERROR_TIMEOUT_D
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int DHTNEW::_readSensor()
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{
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// INIT BUFFERVAR TO RECEIVE DATA
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uint8_t mask = 0x80;
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uint8_t idx = 0;
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// EMPTY BUFFER
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for (uint8_t i = 0; i < 5; i++) _bits[i] = 0;
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// REQUEST SAMPLE - SEND WAKEUP TO SENSOR
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pinMode(_dataPin, OUTPUT);
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digitalWrite(_dataPin, LOW);
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// HANDLE SI7021 separately (see #79)
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if (_type == 70)
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{
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delayMicroseconds(DHTLIB_SI7021_WAKEUP); // hardcoded for now
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}
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else
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{
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// WAKE UP - add 10% extra for timing inaccuracies in sensor.
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uint32_t startWakeup = micros();
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do
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{
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// HANDLE PENDING IRQ
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yield();
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// 180 gives good wakeup delay on UNO for DHT22 / DHT11 (issue #72)
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delayMicroseconds(180UL);
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}
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while((micros() - startWakeup) < _wakeupDelay);
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}
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// HOST GIVES CONTROL TO SENSOR
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digitalWrite(_dataPin, HIGH);
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delayMicroseconds(2);
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pinMode(_dataPin, INPUT_PULLUP);
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// DISABLE INTERRUPTS when clock in the bits
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if (_disableIRQ)
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{
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#if defined(ESP32)
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portDISABLE_INTERRUPTS();
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#else
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noInterrupts();
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#endif
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}
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// DHT22 (and others including Si7021)
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// SENSOR PULLS LOW after 20-40 us => if stays HIGH ==> device not ready
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// timeout is 20 us less due to delay() above
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// DHT11
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// SENSOR PULLS LOW after 6000-10000 us
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uint32_t WAITFORSENSOR = 50;
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if (_type == 11) WAITFORSENSOR = 15000UL;
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if (_waitFor(LOW, WAITFORSENSOR)) return DHTLIB_ERROR_SENSOR_NOT_READY;
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// SENSOR STAYS LOW for ~80 us => or TIMEOUT
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if (_waitFor(HIGH, 90)) return DHTLIB_ERROR_TIMEOUT_A;
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// SENSOR STAYS HIGH for ~80 us => or TIMEOUT
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if (_waitFor(LOW, 90)) return DHTLIB_ERROR_TIMEOUT_B;
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// SENSOR HAS NOW SEND ACKNOWLEDGE ON WAKEUP
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// NOW IT SENDS THE BITS
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// READ THE OUTPUT - 40 BITS => 5 BYTES
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for (uint8_t i = 40; i != 0; i--)
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{
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// EACH BIT START WITH ~50 us LOW
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if (_waitFor(HIGH, 90))
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{
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// Most critical timeout
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// Serial.print("IC: ");
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// Serial.println(i);
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return DHTLIB_ERROR_TIMEOUT_C;
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}
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// DURATION OF HIGH DETERMINES 0 or 1
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// 26-28 us ==> 0
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// 70 us ==> 1
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uint32_t t = micros();
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if (_waitFor(LOW, 90))
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{
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// Serial.print("ID: ");
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// Serial.println(i);
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return DHTLIB_ERROR_TIMEOUT_D;
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}
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if ((micros() - t) > DHTLIB_BIT_THRESHOLD)
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{
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_bits[idx] |= mask;
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}
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// PREPARE FOR NEXT BIT
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mask >>= 1;
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if (mask == 0) // next byte?
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{
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mask = 0x80;
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idx++;
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}
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}
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// After 40 bits the sensor pulls the line LOW for 50 us
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// No functional need to wait for this one
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// if (_waitFor(HIGH, 60)) return DHTLIB_ERROR_TIMEOUT_E;
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// CATCH RIGHTSHIFT BUG ESP (only 1 single bit shift)
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// humidity is maximum 1000 = 0x03E8 for DHT22 and 0x6400 for DHT11
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// so most significant bit may never be set.
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if (_bits[0] & 0x80) return DHTLIB_ERROR_BIT_SHIFT;
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return DHTLIB_OK;
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}
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// returns true if timeout has passed.
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// returns false if timeout is not reached and state is seen.
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bool DHTNEW::_waitFor(uint8_t state, uint32_t timeout)
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{
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uint32_t start = micros();
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uint8_t count = 2;
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while ((micros() - start) < timeout)
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{
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// d elayMicroseconds(1); // less # reads ==> minimizes # glitch reads
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if (digitalRead(_dataPin) == state)
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{
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count--;
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if (count == 0) return false; // requested state seen count times
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}
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}
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return true;
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}
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// -- END OF FILE --
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