Bluetooth Connectivity

I had recently purchased the dev kit package for the PineTime watch (one unsealed, one sealed) and have been having a lot of fun playing around with it. It's a new area for me and I've definitely learned a good deal from it!

With that being said, I want to stress that I'm by no means an expert with things like Bluetooth. I understand how it works and how to interact with it via code, but I couldn't tell you all the truly intricate details of it.

For reference, any tests or scenarios I mention below are using InfiniTime 1.6 with a custom app I had put on it to act as a simple remote control. I based the structure of the app off of the Music app's play/pause button implementation since that was essentially what I needed, just for a different use case that connects to my PC. It has been working perfectly fine and doing exactly what I expected in terms of functionality.

However, the one issue I've had is in regards to the Bluetooth cutting out more than I would've expected it to. There are times where I'm in direct line-of-sight of the adapter for my PC, standing approximately 12 - 15 or so feet from it, and it would start to get more latency and then typically disconnect. It would then reconnect intermittently until I got closer to the adapter, at which point it would be fine again. This would also happen if I was right below the adapter in my kitchen (maybe 7 or so feet, with only a few 2x4s separating the top of the kitchen from the floor above).

So, I tried the following to diagnose it:
  • Connected to my phone instead of the PC adapter. Had the same results
  • Tried a different PC adapter. Same results
  • Tried using both the sealed and unsealed watches in the same situations described above. Had the same results for both in all cases

At this point I wasn't too sure what to think. I know that the connectivity varies on every device and some devices just have shorter ranges, so maybe that was just a limitation. Then, for some reason (I don't really even remember why I thought this), I figured "I've been wearing the watch in all these tests. What if I just hold it by the strap?"

I walked over to one of the places that I had these issues at and held the watch by the strap, and noted that there was barely - if any - latency. I moved my hand around holding the watch (lifting it up, moving it down, further away, closer, etc); still no issues. I figured this may just be a lucky fluke, so I tried other places I had issues at and to my surprise, still had no problems.

To see if I had finally lost my mind, I took the other watch and tried the same tests. I had the same results when holding it from the strap: no notable issues.Then, I took the watch, and laid it over my arm (didn't strap it on, just laid it down), and suddenly the connection died off.

I repeated the above experiment several times, with both watches, and every time I had the same results. Whenever I put the watch on my wrist, the connectivity would be cut off to a pretty extreme amount. I know that Bluetooth can't travel through water, and given that we're just walking, talking water sacs, it does add up that my body blocking the watch would reduce signal.

As another experiment, I bent the end of the Bluetooth antenna in my dev watch upwards a bit so that it was more vertical inside the case. My main reasoning was (rather simply) that antennas typically seem to point vertically from their base, so I have nothing to lose by trying that here. To my surprise, this actually seemed to reduce the issues I had while wearing the watch by a significant amount; not a complete fix, but certainly much better. Conversely, the sealed watch still had issues where the dev watch no longer did.

So with all that out of the way, my main questions:
  • Is wearing the watch supposed to affect connectivity? Like I said above, I understand that our bodies block signal, but it seems kind of bizarre that wearing the watch - one of the main functions of it - would decrease connectivity by such a noticeable amount, no?
  • Does it really make sense that my slight bending of the antenna would've increased performance to such a noticeable degree?
  • Is there just something else here that I'm overlooking, or other factors that are just making this a red herring?

I also apologize if this is the wrong sub-forum. I figured since after all my tests it seemed hardware related, I would ask here.

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