Reply to post: Re: One would have throught...

Re: One would have throught...

> You are suffering from 'one-bit mind'. This is where people assume that quantities which need to be represented by real numbers (or collections of real numbers) can be represented by a single bit, which is either true or false. It's a common problem among computing people: I suffer from it too.

I think it's more around the question: how useful is this information, and how many false positives will it trigger?

Class 2.0 Bluetooth theoretically has a range of 10m. Which obviously varies depending on location and device, but hey.

And it apparently takes a minimum of 1.28 seconds to get a response from a bluetooth device in low power mode, and an average of around 2 seconds.

(http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.1015.2811&rep=rep1&type=pdf)

And average walking speed is about 1.4m/s.

So. You have a bluetooth "bubble" around each person, with a 20m diameter. So if two people walk past each other, they'll be in each other's range for around 7 seconds, and the system will record that they were in "kissing" range for about 5 of those seconds.

Ping.

Or if one of the people is stationary, they'll be in range for around 14 seconds, and the system will record 12 seconds.

Ping.

Or if I'm sat upstairs at the back of a double-decker bus, and someone else sits at the back of the bottom of the double-decker bus, we'll be in range until one of us gets off the bus, despite having always had a solid metal barrier between us.

And that doesn't count the people we'll pass while sitting on the bus, especially if it's an inner-city environment where buses often travel at little more than walking pace.

Or if I'm at work, where many of the offices have full-height glass windows and thin partition walls. Yet more people I would have zero physical contact with, but could spend hours in range of their BT devices.

And so on.

I'm guessing there's ways to filter the results from these checks and reduce false positives. But it's a non-trivial exercise, and if the boy cries wolf too often, the usefulness of this application will rapidly dwindle.