DHT12

Arduino library for I2C DHT12 temperature and humidity sensor.

Description

The library should be initiated by calling the begin() function, optionally begin(dataPin, clockPin) for ESP32 and similar platforms.

Thereafter one has to call the read() function to do the actual reading, and with getTemperature() and getHumidity() to get the read values. Calling these latter again will return the same values until a new read() is called.

Interface

Constructor

DHT12(TwoWire *wire) constructor, using a specific Wire (I2C bus).
bool begin(uint8_t dataPin, uint8_t clockPin) begin for ESP32 et al, to set I2C bus pins
bool begin() initializer for non ESP32. Returns true if connected.
bool isConnected() returns true if the address of the DHT12 can be seen on the I2C bus. (since 0.3.2)

Core

int8_t read() read the sensor and store the values internally. It returns the status of the read which should be 0.
float getHumidity() returns last Humidity read, or -999 in case of error.
float getTemperature() returns last Temperature read, or -999 in case of error.
uint32_t lastRead() returns the timestamp in milliseconds since startup of the last successful read. (added in 0.3.1)

Offset

void setHumOffset(float offset) set an offset to calibrate (1st order) the sensor.
float getHumOffset() return current offset, default 0.
void setTempOffset(float offset) set an offset to calibrate (1st order) the sensor
float getTempOffset() return current offset, default 0.

0.3.0

The members temperature and humidity became private in 0.3.0.
added offset for temperature and humidity.

Operation

See examples

Future

check for optimizations. although I2C overhead is much more...
test at different I2C speeds 400 KHz should be possible.
add examples.
void setIgnoreChecksum(bool = false) ignore checksum flag speeds up communication a bit
bool getIgnoreChecksum() get status. for completeness.

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