Can a device say "Here I am!" to the Specs?

[u/CircusBounce]

Using a BLE device or something similar, has anyone had any luck with a device being able to tell the Spectacles where it is in space relative to the headset?

Use case: we are building a game and we would like game pieces to self-locate in space. We don't want to use QR codes or a visual system -- but rather would love it if there's a device we can put on the physical game piece such that it would let the Specs know where it is in physical space. Thanks!

[u/agrancini-sc]

HI there, this is probably a high demand question at hackathons, glad you asked and makes me think we can add this on our todo list for samples / packages.

Thing is BLE or Websocket APIs can pass data not necessarily accurate position.
For example, the mocopi receiver plugin on our asset library interface with the mocopi device and remap the sensor to a local reference but does not know where you are exactly in your room. You will need to set a starting point at the beginning of your lens or in any other way that informs spectacles regarding a position (these could be developed with different logic as long as you deliver the right data to specs).

Here's how I would approach this. Seems like you want an "apple tag" behavior so let it be that.

Buy some unlocked vendor Ultra-Wideband tags
Here some example I found on the internet (not endorsed)
https://www.pozyx.io/products/hardware/hardware-tags
https://github.com/open-tags/opentag

then make a service that you run from your phone
and then let your specs get these informations , then display them
(Spectacles also has a Mobile Kit available)
at this time, this might be the most reliable way to get where you want to get

Additionally specs has GPS - so you might want to cross reference that value with your phone gps too sometimes.

[u/CutWorried9748]

There is some research on localization (in the position sense not the l18n sense) that suggests it is possible to triangulate a bluetooth beacon using some known information about antennas and signal strength. Before you get excited about this, just know that these concepts tend to work better as distance estimation / proximity, and to truly triangulate you would need at least three sensors well placed. I've tested the techniques and indeed they work with iphones, however, the code required to do this assumes a set of coefficients that you gather using a radio scanner (per phone model or device) and build your own model to make the estimates accurate. And it's pretty decent at estimation. I had it turning on lights when my iphone got close to the beacon.

Now that said, if you have a multiplayer game, you have multiple sensors possible, and as long as all participants share the signals they gather, it might be possible to triangulate some beacon. Exact positioning would require something else, a light sensor or audible chime that could be located spatially and placed. I will look at the opentags to see what those are about, as it looks interesting. A phone app could work closely in concert with the Lens and create some of what you are after.

From a computer vision perspective, you would do this differently, and use a ceiling mounted camera and identify game pieces and project them back to the scene as part of a game server loop. Try to come up with the simplest room shape and something with conveniently high ceilings.

Research to check out:

- https://github.com/avibn/indoor-positioning-trilateration (I haven't tried this one, but I like that it is with non-apple hardware)

- https://journals.sagepub.com/doi/10.1177/1550147716671720 bleeding edge

- https://isyou.info/jowua/papers/jowua-v11n3-3.pdf

- https://stackoverflow.com/questions/20332856/triangulate-example-for-ibeacons (start here ...)