[chbot] CovidCard implementation - how expensive should it be to manufacture 1M of them?

[Robin Gilks]

>      *   broadcast once per minute its own ID and nothing else

Do you think that is often enough? I would have thought closer to once per
second otherwise you miss the very close contacts that don't last very
long.

Bluetooth Low Energy can beacon quite comfortably at this rate but the
scanning takes more effort (and power) as there are 3 channels to check
and they need to be continuously listened to (within the confines of the
BLE frequency hopping) otherwise again you miss close contacts.

Assuming just using RSSI to determine distance, orientation will affect
the signal by up to at least 30dB but at least the transmit power can be
turned right down as only 2m radius is of interest. Multiple reading
averages will still have to be used due to signal strength fluctuations.

It also tricky finding a cheap solution that can do both Central and
Peripheral roles simultaneously.

-- 
Robin Gilks