New 'smart' diaper can alert caregiver when it is time to change

For some infants, a wet diaper is cause for an instant, vociferous demand to be changed, while other babies may be unfazed and happy to haul around the damp cargo for lengthy periods without complaint. But if worn too long, a wet diaper can cause painful rashes, and miserable babies -- and parents. New 'smart' diaper can alert caregiver when it is time to change