London, May 17 : An Indian-origin researcher in the US has conceived a way to make air conditioners that can track human movement through the different rooms of a house.
Shwetak Patel of the Atlanta-based Georgia Institute of Technology says that his idea is based on a device that detects small differences in air pressure as people pass from one room to another.
He believes that his device may make air conditioning systems more intelligent, and reduce energy consumption.
He says that his device offers a cheaper alternative to motion sensors when it comes to tracking human activity in homes.
Patel says that all that is required to make it work is a modification to a house's heating, ventilation and air-conditioning (HVAC) system that circulates air throughout the house using a system of ducts.
He says that air circulation reaches a steady state in an empty house, but the airflow gets disturbed when somebody opens and closes doors to move in or move out.
According to him, such tiny disturbances to airflow can be detected simply by placing five air-pressure sensors on the filter that lies at the centre of the HVAC system.
He says that the sensor data could be analysed using software to identify which particular door was active in a 10-20 room house 75 to 80 per cent of the time.
The researcher says that the software may also detect when a person walked through a particular door 60 to 75 per cent of the time.
"When a door movement event occurs, the pressure differentials are slightly different at each of the sensors," New Scientist quoted him as saying.
Patel says that his system may even help transform HVAC's into burglar alarms, which would be triggered when a door in an empty house is opened.
His idea has impressed of Massachusetts-based Mitsubishi Electric Research Laboratories so much that he is experimenting with "Big Brother" buildings stuffed with motion sensors as an alternative to CCTV.
"I really like this fresh and unexpected look at things. With machine-learning methods, one can observe how the pressure changes and then figure out roughly where it happened in the house," he says.
Patel is now testing the system on larger homes and office buildings.
He says that one big challenge before him is to make the system conducive to larger buildings that tend to have long ducts.
"The signature between two different locations might start to look very similar," he says.
He will make a presentation on the aircon surveillance system at the International Conference on Pervasive Computing in Sydney, Australia, this month.