You all should seriously look at ESP8266/NodeMCU 
What would be cool, if I ever can find time, would be to make a generic arduino firmware that sent all the ESP8266 pin and analog status to SmartThings. Then have a configurable SmartThings DH that let you configure what each pin on ESP is doing:
ADC0=light sensor
GPIO1=DHT22 temperature/humidity
GPIO2=contact sensor
GPIO3=motion sensor
etc…
The DH selectable options could be numerous for each GPIO…
-ANALOGIN-Gas Sensor
-ANALOGIN-Light Sensor
-IN-DHT-22 Temperature/Humidity
-IN-Contact
-IN-Motion
-IN-Leak
-OUT-LED-Red PWM
-OUT-LED-Green PWM
-OUT-LED-Blue PWM
-OUT-Buzzer
-OUT-Relay