Bhupendra Singh
Hardware prototype

रक्षा Rakshaprotection

A room that knows you are there. No camera.

Millimetre-wave radar reads movement, distance and the rise and fall of a chest. It can tell an empty room from a sleeping one and a sitting person from a fallen one, and it does all of it without ever forming a picture.

No lens, ever Nothing leaves the house mmWave radar

What it can tell apart.

Radar does not see shapes. It sees things moving toward and away from it, and how far off they are. Almost everything useful comes from that one measurement.

empty / occupied A room with nobody in it returns a still signal. A person breathing does not, even asleep and perfectly motionless otherwise.
upright / lying down Height off the floor is a distance measurement, so standing, sitting and lying are three clearly different readings.
moved / fell Lying down is ordinary. Dropping quickly to the floor and then not moving is the pattern worth reacting to.
one / more than one Two people breathe at different rates and sit at different distances, so they separate into two returns.

What it cannot do.

The limits are the product. A sensor that could do more of this would be a sensor I would not want in my mother's house.

Know who you are

There is no face, no voice and no gait signature precise enough to name a person. It knows a body is present, not whose.

and there is no version of this that adds it

Produce footage

Nothing recorded can be replayed as an image, because nothing image-shaped is ever captured. There is no archive to subpoena, leak or regret.

the reason the whole thing uses radar

Cover a whole house

One unit reads one room, and thick walls and metal stop it. A house needs several, and each one is another thing to fail.

range and wall penetration still being measured

Never be wrong

A large dog, a falling object and a person can look similar to a sensor that only measures motion and distance. False alarms are the failure mode that gets a device unplugged.

the thing that decides whether it ships

What is true today.

Raksha is a board on a desk, not a product. There is nothing to buy and no date.

Working on the bench

  • Presence and distance readings from a single room, live
  • Standing, sitting and lying separate reliably in a quiet room
  • All processing on the device, with no network and nothing stored

Not solved

  • False positives, which is the whole problem, not a detail of it
  • What a household should actually be shown day to day, when working looks like nothing happening
  • Enclosure, certification, and everything else that separates a board from a device