Is it possible to sync Bangle.js 2 time to smartphone time?

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malaire

@myownself

I think connecting will result in a much more accurate time than relying on the right advertisement being picked up at the right time.

I thought so too but in my tests that connection takes several seconds while advertisement-solution can be improved down to e.g. 50ms delay between updating advertisement, so using connection is a lot worse for some reason.

@fanoush

bluetoth timing is strict, advertising packets are timed/spaced in deterministic way

No it's not deterministic - Bluetooth protocol has builtin random delay for timing which is around 10 ms or so, so accuracy better than that is not possible using normal API. (But yeah it's good enough.)

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fanoush in reply to @malaire

No it's not deterministic - Bluetooth protocol has builtin random delay for timing which is around 10 ms or so

Oh, you are right for the advertising, there is delay indeed. Decribed e.g. here https://www.argenox.com/library/bluetooth-low-energy/ble-advertising-primer/ didn't know this. Makes sense. However it is not like that for the rest, the rest has strict timing so receiver device can wake at the precise moment sender is supposed to send the packet, that is part of the 'low energy'.

But anyway even with advertising the timing for scan response packet may be better. This is with active scanning, it is second packet for advertising data.

EDIT:
Scan response is more deterministic, see https://devzone.nordicsemi.com/f/nordic-q-a/29719/beacon-scan-response-request-and-packet-timing

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