The DHt12 is an upgraded version of the classic DHT11 humidity temperature sensor, it is fully downward compatible, more precise and adds an I2C interface.
Features:
compact size
low power consumption
low voltage operation
Standard I2C and 1-wire interface.
Sensing range
Temperature: -20 ~ +60 C
Humidity: 20-95 RH
Humidity:
Resolution: 0.1%RH
Repeat: -+ 1%RH
Precision 25C @ -+5RH
Temperature:
Resolution: 0.1C
Repeat: -+0.2C
Precision: 25C @ -+0.5C
Power: DC 2.7-5.5V
Normal current 1mA
Standby current 60uA
Sample cycle: > 2 seconds
Pin interface: 1. VDD 2. SDA 3. GND 4. SCL (connect to GND when use as 1-wire)
Layout
This shows how to connect the DHT12 to a Raspberry Pi
Code
[codesyntax lang=”python”]
import smbus
DEVICE = 0x5C #device I2C address
bus = smbus.SMBus(1)
def readdata(addr=DEVICE):
#read 5 bytes of data from the device address (0x05C) starting from an offset of zero
data = bus.read_i2c_block_data(addr,0x00, 5)
print “Humidity = ” + str(data[0]) + “.” + str(data[1]) + “%”
print “Temperature : ” + str(data[2]) + “.” + str(data[3]) + “C”
if (data[0] + data[1] + data[2] + data[3] == data[4]):
print “checksum is correct”
else:
print “checksum is incorrect”
if __name__==”__main__”:
readdata()
[/codesyntax]
Output
Link
Under $1 for one of these sensors
1pcs DHT-12 DHT12 sensor Digital output Temperature and Humidity Sensor high quality
