Passive RFID Tags Can Identify Human Behaviour In The Home

Passive RFID Tags Can Identify Human Behaviour In The Home

The system, dubbed IDAct, uses ‘long-range’ (a few metres) 900MHz passive UHF tags and a single antenna in the ceiling of each room.

Tags were attached to household items such as a knife, vacuum cleaner or pickle jar, and volunteers performed 24 activities including: blend a smoothie, roast chicken and potatoes, climb the stairs, mop the floor and brush their hair.

Data came from dynamic changes in received signal strength and received signal phase as objects were moved by the volunteers, or when the body of a volunteer changed the electromagnetic environment around stationary objects, or a combination of both – made richer because the reader frequency-hops five times a second, giving multiple strength and phase parameters.

“In the 26 hours of data collected with 110 objects across 10 participants, our analysis shows that IDAct can detect user presence with an F1 [accuracy] score of 96.7%, and recognise 24 different daily activities with an F1 score of 82.8%,” according to the IEEE paper ‘IDAct: Towards Unobtrusive Recognition of UserPresence and Daily Activities‘, which describes the work, and goes on to say: “Our approach does not require extensive training for specific objects or the sensing environment. The interaction detection algorithm utilised allows it to adapt to different user and RF environments, lowing its deployment barrier.”

The team tested the technology by outfitting a volunteer’s apartment with a series of RFID readers and then tagging household objects with (radio frequency identification) RFID tags. They collected 26 hours of data from each room while users were present, and also collected two hours of data from empty rooms as a control.

For the experiments, machine learning, then algorithmic object classification and movement classification, was performed on a laptop, but the team sees this processing being built into a suitable RFID reader.

The whole paper is available free, and contains a lot of clear detailed information, although sadly appears to have had a trip through a marketing department – forgive me if I am wrong on that last part.