Radar-based systems adaptable to smart homes – New Electronics (blog)

Is the concept of living in a smart home making people excited enough for it to become really important to our lives and, perhaps more importantly, for those working in high-tech industries, a solid and sizeable market?
The transition from dumb buildings to smart buildings was always going to be slow. Services such as lighting and heating tend to have very long lifetimes. Adding smart technologies incrementally, or integrating these with existing systems, can be difficult or impossible. On the other hand, a major upgrade project is always expensive and disruptive.
In workplaces or commercial buildings, upgrading to smart technologies can make perfect sense. These types of buildings are often refitted, for example when a new company moves into an existing building, or as part of major reorganisation or rebranding. Budgets can be unashamedly large, and a new headquarters packed with smart technologies can bring valuable corporate kudos.
In contrast, a sizeable number of consumers can be somewhat more reluctant to splash out on smart tech for the home. Some can simply be difficult to persuade that it’s worth spending a lot of money to save turning lights on or adjusting the thermostat themselves. Maybe the smart home needs to do more for us if it is to be really compelling. Put simply, smart homes need to get smarter.
A smart home that takes care of our personal safety could be more attractive to some homeowners, particularly the elderly or people who need to balance work commitments with caring for ageing or sick family members. It could be a while before walking and talking robots are able to take on these types of roles, so a smart home that cares could be the answer. But how can sensors in the home detect when someone inside needs help?
Currently, occupancy detection remains the preserve of the trusty passive infrared (PIR) sensor, these have become well established over many years in security systems, and the latest models are much smaller as well as more controllable and dependable than their predecessors. Even so, PIR detectors continue to depend on changes occurring in the surveyed scene to detect the presence of a person, and although this can work well to prevent a burglar making off with the family silver, it is less effective if the homeowner has had an accident while alone and may be unconscious or unable to move.

Radar to the Rescue
A Digi-Key’s TechZone article Making Smart Home Sensors Tell Us More‘ takes a look at how radar technology could provide an answer. It may sound outlandish, but the automotive market has driven the development of radar modules used in driver-assistance systems such as object detection and collision avoidance. The technology is now available within miniature form factors and low power consumption, and – crucially – is affordable for consumer applications.
After briefly reviewing the state of the art in PIR sensors, the article moves on to discuss the capabilities radar-based occupancy sensing may bring to the next generation of smart homes. TechZone being TechZone, there is also a look at the architecture of a radar-based occupancy sensor built with components that are available in the market right now.
Some of the advantages of radar-based sensing are that the technology is not dependent on movement or temperature differential in order to detect occupancy. On the other hand, it is capable of detecting minute movements such as tiny gestures or even the motion of an occupant’s chest due to breathing. This is ideal in the event that an elderly person, for example, has had a fall and has been lying still for some time unable to get up. If a pair of sensors are used, the position of the occupant can also be calculated. From this data, the controller can generate an alarm and provide useful information for relatives, carers or emergency services. The information is detailed and reliable, and yet is gathered in a far less invasive way than, for example, video surveillance, which is generally considered unacceptable in the context of in-home care.
Miniature, consumer-class radar enabling smart homes to take better care of their occupants could help to improve quality of life and make a stronger case for smart building technologies in the residential market.

To read the article, follow the link: Making Smart Home Sensors Tell Us More

Author profile
Jason Gums is product manager of semiconductors at Digi-Key Electronics.

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