You’ve dredged up a very old thread. These days, most everyone would implement this “clapper” functionality using voice commands from a very low cost Amazon Dot or Google Home Mini. Both of these solutions are much lower cost than the Arduino + ThingShield, have native ST integration, and offer much more than a simple clapper functionality (music, light control, dimming control, weather reports, executing routines, etc…)
PS - The ThingShield is no longer offered for sale by SmartThings. If you want an alternative, try out my ST_Anything project which supports numerous microcontrollers and network connectivity options.
These days, most everyone would implement this “clapper” functionality using voice commands from a very low cost Amazon Dot or Google Home Mini. Both of these solutions are much lower cost than the Arduino + ThingShield, have native ST integration, and offer much more than a simple clapper functionality (music, light control, dimming control, weather reports, executing routines, etc…)