Setting up the software

This time, to implement the software of this prototype, we can use a state-machine with the following states and their relative transactions:

State	Description	Actions	Transaction conditions
IDLE	Idle state; the washing machine is not working.	LED yellow off LED red off	If sound is detected, set t0=t and move state to SOUND.
SOUND	Sound detected! Keep monitoring the environment for a while.	LED yellow is blinking LED red is off	If sound is detected and t-t0 > timeout, move to RUNNING.
RUNNING	Continuous sound detected so the washing machine has started its job.	LED yellow is on LED red is off Alert the user	If no sound is detected, set t0=t and move to NO_SOUND.
NO_SOUND	No more sound detected! Keep monitoring the environment for a while.	LED yellow is on LED red is blinking	If no sound is detected and t-t0 > timeout, move to DONE. If sound is detected, move to RUNNING.
DONE	No more sound for a long delay; the washing machine has finished...