The Arduino Temperature and Humidity sensor DHT11 is a basic device with a temperature sensing accuracy of +/- 2 degrees C, and a humidity resolution of +/- 5% relative humidity. It has a working range of 20 to 90% relative humidit, and 0 to 50 degrees C. The DHT11 employs a nonstandard one-wire serial communications protocol. It works using a signal-responce approach. The microcontroller pulls the single signal line low for a brief period of time, followed by allowing it to go high via its built in pull up resistor. The DHT11 responds with 40 bits of serial data, organized as 5 8-bit data values.
All prices are in USD