idDHTLib
Interrupt driven DHT11 & DHT22 temperature and humidity sensor Arduino library.
Usage
Instantiate the sensor object
// for DHT11
idDHTLib DHTLib(pinNumber);
// for DHT11 and DHT22, sensorType can be idDHTLib::DHT11 or idDHTLib::DHT22
idDHTLib DHTLib(pinNumber, sensorType);pinNumber is the digital pin number from the Arduino board and must be an external interrupt capable pin
| Board | int.0 | int.1 | int.2 | int.3 | int.4 | int.5 |
|---|---|---|---|---|---|---|
| Uno, Ethernet | 2 | 3 | ||||
| Mega2560 | 2 | 3 | 21 | 20 | 19 | 18 |
| Leonardo | 3 | 2 | 0 | 1 | ||
| Due | (any pin, more info http://arduino.cc/en/Reference/AttachInterrupt) | |||||
Start the reading
The sensor reading can be started with one of these methods
//lasts about 18ms
DHTLib.acquire();
//lasts a few uS but need the acquiring() function to be called at intervals < 10ms
//this should be used in cases where the other tasks in the loop() have to respond fast
DHTLib.acquireFastLoop();
//blocks the execution until the reading is complete
DHTLib.acquireAndWait();Checking for completion
DHTLib.acquiring() //returns false when reading is complete (or not started)Checking for errors
After the reading is complete
DHTLib.getStatus() - returns one of these values
- IDDHTLIB_OK - the reading was successful
- IDDHTLIB_ERROR_CHECKSUM
- IDDHTLIB_ERROR_TIMEOUT
- IDDHTLIB_ERROR_ACQUIRING
- IDDHTLIB_ERROR_DELTA
- IDDHTLIB_ERROR_NOTSTARTED
Sensor data
After the reading is complete and the status was IDDHTLIB_OK
DHTLib.getCelsius() // float
DHTLib.getFahrenheit() // float
DHTLib.getKelvin() // float
DHTLib.getDewPoint() // double, 5x faster than dewPointSlow(), delta max = 0.6544 wrt dewPointSlow()
DHTLib.getDewPointSlow() // double
DHTLib.getHumidity() // float Basic example
idDHTLib DHTLib(2, idDHTLib::DHT11);
void setup() {
Serial.begin(9600);
}
void loop() {
int result = DHTLib.acquireAndWait();
if (result == IDDHTLIB_OK) {
Serial.print("Humidity (%): ");
Serial.println(DHTLib.getHumidity(), 2);
Serial.print("Temperature (oC): ");
Serial.println(DHTLib.getCelsius(), 2);
Serial.print("Temperature (oF): ");
Serial.println(DHTLib.getFahrenheit(), 2);
Serial.print("Temperature (K): ");
Serial.println(DHTLib.getKelvin(), 2);
Serial.print("Dew Point (oC): ");
Serial.println(DHTLib.getDewPoint());
Serial.print("Dew Point Slow (oC): ");
Serial.println(DHTLib.getDewPointSlow());
} else {
Serial.println("Error");
}
delay(2000);
}Changelog
- v 0.0.1
- fork from idDHT11 lib
- change names to idDHTLib
- added DHT22 functionality
- v 0.0.2
- Optimization on shift var (pylon from Arduino Forum)
- v 0.0.3
- Timing correction to finally work properly on DHT22 (Dessimat0r from Arduino forum)
- v 1.0.0
- autoformat code with Arduino IDE code formatting standards (kcsoft)
- remove the interrupt number from the constructor by using digitalPinToInterrupt (kcsoft)
- fix type for us and timeout when no interrupt is triggered (kcsoft)
- removed the callback parameter from the constructor, added sensor type (DHT11, DHT22) as optional param (kcsoft)
- removed temp/humid calculation from the isr (kcsoft)
- new function acquireFastLoop to remove delay when start acquiring (kcsoft)
- update README.md file (kcsoft)
Datasheet
Based on
idDHT11 library
DHTLib library
Code proposed on Arduino forum