Telling people apart by weight

A bathroom scale shared by a household reports a number and says nothing about who stood on it. The ANKO integration has to decide.

First, decide what the reading is. A scale broadcasts continuously while someone steps on, shifts and steps off. A reading counts once three consecutive advertisements agree within 0.5 kg inside five seconds, or, failing that, the last stable ones after five seconds of silence.

Then decide whose it is. Each person has an expected weight, kept as a moving average that gives the newest reading a weight of 0.3. A new reading goes to the person whose expected weight is closest, provided it is within 5 kg or 7% of it, whichever is larger, and provided the next closest person is at least 2 kg further away.

Otherwise, do not guess. A reading that fits two people, or nobody, is held as pending and raised as a repair for someone to assign by hand.

Two things changed after the first version. People moved out of the scale’s configuration into their own entry, so a household with two scales has one set of people. And the diagnostics download stopped including names, which it had been leaking.

The limit is plain: two people of similar weight cannot be told apart this way.