Interrupt driven DHT 11/21/22 sensor library for esp8266
If you get too many checksum or timing out err, set cpu frequency to 160MHz

result with two sketch

test(still running...)

160MHz/5sec report: 13.13H, 9400, err : 20(large sketch, too many err with 80MHz)

80MHz/5sec report: 8.1H, 5816, err : 0(simple sketch)

Interrupt driven DHT 11/21/22 sensor library for Spark

Supports reading DHT22/DHT21/DHT11 sensors without disabling interrupts

Scott Piette, Piette Technologies - scott.piette@gmail.com
Jan 18, 2014  - Initial port to Spark Core
Oct  1, 2014  - Added DHT11/21 support, fixed timing issues, enhanced examples

VERSION:	0.2
PURPOSE:	Interrupt driven non-blocking library for DHT sensors
LICENSE:	GPL v3 (http://www.gnu.org/licenses/gpl.html)

BASED ON:

DHT11 interrupt library https://github.com/niesteszeck
DHT11 library http://playground.arduino.cc/Main/DHT11Lib

Wiring diagram for Spark Core with DHT22 Sensor

DATASHEETS:

DHT11	http://akizukidenshi.com/download/ds/aosong/dht11.pdf
DHT22	https://www.sparkfun.com/datasheets/Sensors/Temperature/DHT22.pdf