// // FILE: DHT2pin.cpp // AUTHOR: Rob Tillaart // VERSION: 0.1.2 // PURPOSE: Experimental DHT Temperature & Humidity Sensor library for Arduino // URL: https://github.com/RobTillaart/DHT2pin // http://arduino.cc/playground/Main/DHTLib // // HISTORY: // 0.1.2 2021-12-16 update library.json, license, minor edits // 0.1.1 2020-12-19 added arduino-ci + unit test // 0.1.0 2020-06-30 own repository; #pragma once // 0.0.3 Fix issue #33 // 0.0.2 support for non "F_CPU" boards especially Galileo // Tested and verified by Maria Emanuella Moura Silva (thanks) // changed name to DHT2pin // 0.0.1 initial version - 2016 SEP 05 (based upon 0.1.13 DHT) // #include "DHT2pin.h" ///////////////////////////////////////////////////// // // PUBLIC // // return values: // DHTLIB_OK // DHTLIB_ERROR_CHECKSUM // DHTLIB_ERROR_TIMEOUT int DHT2pin::read11() { // READ VALUES int rv = _readSensor(DHTLIB_DHT11_WAKEUP); if (rv != DHTLIB_OK) { humidity = DHTLIB_INVALID_VALUE; // invalid value, or is NaN prefered? temperature = DHTLIB_INVALID_VALUE; // invalid value return rv; } // CONVERT AND STORE humidity = bits[0]; // bits[1] == 0; temperature = bits[2]; // bits[3] == 0; // TEST CHECKSUM // bits[1] && bits[3] both 0 uint8_t sum = bits[0] + bits[2]; if (bits[4] != sum) return DHTLIB_ERROR_CHECKSUM; return DHTLIB_OK; } // return values: // DHTLIB_OK // DHTLIB_ERROR_CHECKSUM // DHTLIB_ERROR_TIMEOUT int DHT2pin::read() { // READ VALUES int rv = _readSensor(DHTLIB_DHT_WAKEUP); if (rv != DHTLIB_OK) { humidity = DHTLIB_INVALID_VALUE; // invalid value, or is NaN prefered? temperature = DHTLIB_INVALID_VALUE; // invalid value return rv; // propagate error value } // CONVERT AND STORE humidity = word(bits[0], bits[1]) * 0.1; temperature = word(bits[2] & 0x7F, bits[3]) * 0.1; if (bits[2] & 0x80) // negative temperature { temperature = -temperature; } // TEST CHECKSUM uint8_t sum = bits[0] + bits[1] + bits[2] + bits[3]; if (bits[4] != sum) { return DHTLIB_ERROR_CHECKSUM; } return DHTLIB_OK; } ///////////////////////////////////////////////////// // // PRIVATE // // return values: // DHTLIB_OK // DHTLIB_ERROR_TIMEOUT int DHT2pin::_readSensor(uint8_t wakeupDelay) { // INIT BUFFERVAR TO RECEIVE DATA uint8_t mask = 128; uint8_t idx = 0; // EMPTY BUFFER for (uint8_t i = 0; i < 5; i++) bits[i] = 0; // REQUEST SAMPLE digitalWrite(_wpin, LOW); delay(wakeupDelay); digitalWrite(_wpin, HIGH); delayMicroseconds(40); // GET ACKNOWLEDGE or TIMEOUT uint16_t loopCnt = DHTLIB_TIMEOUT; while(digitalRead(_rpin) == LOW) { if (--loopCnt == 0) return DHTLIB_ERROR_TIMEOUT; } loopCnt = DHTLIB_TIMEOUT; while(digitalRead(_rpin) == HIGH) { if (--loopCnt == 0) return DHTLIB_ERROR_TIMEOUT; } // READ THE OUTPUT - 40 BITS => 5 BYTES for (uint8_t i = 40; i != 0; i--) { loopCnt = DHTLIB_TIMEOUT; while(digitalRead(_rpin) == LOW) { if (--loopCnt == 0) return DHTLIB_ERROR_TIMEOUT; } uint32_t t = micros(); loopCnt = DHTLIB_TIMEOUT; while(digitalRead(_rpin) == HIGH) { if (--loopCnt == 0) return DHTLIB_ERROR_TIMEOUT; } if ((micros() - t) > 40) { bits[idx] |= mask; } mask >>= 1; if (mask == 0) // next byte? { mask = 128; idx++; } } digitalWrite(_wpin, HIGH); return DHTLIB_OK; } // // END OF FILE //