A small Virginia firm hoping to revolutionize the way Americans care for aging family members has unveiled its first prototype of a portable, high-tech dwelling that would provide temporary shelter for a sick or elderly relative in his or her family’s back yard.

On Monday, N2 Care, a company formed by a Methodist minister in Salem, Va., showed off its first MedCottage, a 12-by-24-foot prototype filled with biometric technology that would allow a family and health-care providers to monitor the condition of an aging or disabled relative. The cottage contains air filtration systems, video links, devices that allow the remote monitoring of vital signs and sensors that could detect an occupant’s fall.

Until now, the MedCottage had been an idea on paper only. Even before the prototype was trotted out, however, the company’s concept had received an important endorsement: The Virginia General Assembly this year passed legislation that supersedes local zoning laws and allows families to install such a dwelling on their property with a doctor’s order.

Although the bill passed almost unanimously and Gov. Robert F. McDonnell signed it into law, detractors have dubbed the concept the “granny pod” and predicted that it could create conflicts between neighbors who find the dwellings unsightly. Some critics also worry that the set-up could lead to cases of neglect involving elderly or disabled occupants of the dwellings.