3 ms·

Bluetooth LE uses a client/server (called "central" / "peripheral") model; think of "server" like "web server", typically the client is your smartphone. I coul

by jmah 13y ago

Bluetooth LE uses a client/server (called "central" / "peripheral") model; think of "server" like "web server", typically the client is your smartphone. I could believe that a single peripheral can't simultaneously connect to multiple centrals (I'm just getting started with BTLE), but the typical pattern is for e.g. the heart rate sensor and smartwatch to both be peripherals of a smartphone. The first article you reference says: So for folks that may use one device for cycling and another for running, this could cause issues if both devices tried to connect to the heart rate strap at the same time. As long as you're not cycling and running at the same time, this isn't an issue.

nl 13y ago
I'm pretty heavily in this field (both as a user and occasional developer). I understand the models pretty well, and BTLE has this wrong, because of their smartphone-centric view of the world. For casual fitness stuff they can get away with that, but as you get more hard-core it breaks down pretty quickly. After all, Garmin has built a multi-billion dollar business building devices that where a smartphone can handle 90% of the functionality. For that extra 10% you still need an extra device, and that extra 10% is often the rich, passionate end of the market. Some specific examples: In a triathlon you are unlikely to take your watch off after the swim when you get on your bike. The HR strap will remain paired to the watch and not your bike display (and given than the swim->bike transition and bike->run transition are often in different locations taking it off isn't realistic either). People use gym equipment with built in ANT+ displays, but want to record their workouts on their personal devices. These are both big markets (Garmin/Timex/Sunto/Polar all have specific devices just for them) and BTLE doesn't work in these scenarios. I wish it did, and I hope they will fix it.

by jmah 13y ago

nl 13y ago

I'm pretty heavily in this field (both as a user and occasional developer). I understand the models pretty well, and BTLE has this wrong, because of their smartphone-centric view of the world. For casual fitness stuff they can get away with that, but as you get more hard-core it breaks down pretty quickly. After all, Garmin has built a multi-billion dollar business building devices that where a smartphone can handle 90% of the functionality. For that extra 10% you still need an extra device, and that extra 10% is often the rich, passionate end of the market. Some specific examples: In a triathlon you are unlikely to take your watch off after the swim when you get on your bike. The HR strap will remain paired to the watch and not your bike display (and given than the swim->bike transition and bike->run transition are often in different locations taking it off isn't realistic either). People use gym equipment with built in ANT+ displays, but want to record their workouts on their personal devices. These are both big markets (Garmin/Timex/Sunto/Polar all have specific devices just for them) and BTLE doesn't work in these scenarios. I wish it did, and I hope they will fix it.