Comment by lchengify | Hacker News Reader

Comment by lchengify | Hacker News Reader

Hi Brian! Big Tile user here with some chemistry backround, this is super interesting. Couple of questions:

1. Can you go a bit more into how the battery is integrated into the device? If it's integrated, is it still using standard anodes / cathodes and redox, or is it a capacitor, or is the battery still a separate component? This is normally the trickiest thing (vs the printed circuits on thin films) so this is why I ask.

2. How durable are the tags? Tiles can take quite a hit and still function pretty normally, which is why people use them for things like tagging cats. Do they work underwater? Do they work after element exposure? Any testing around this?

3. How flexible are the tags? Can I wrap them around round objects (this would be huge for me, since right now I am duct-taping tiles to things that are round, which is sub-optimal.

4. Do the devices broadcast how much battery they have left? Tiles have a great feature that tell me early on when they need to be replaced.

Thanks!!

Thanks!

— In the current ones we’re shipping right now, the battery is one of those thin lithium primaries, ~0.45mm. But, in the version that’s coming out, we’re coating the anode and cathode materials on two different substrates and laminating them together on a reel-to-reel process.

— They’re pretty durable, but they are labels (laminated polypropylene and PET) with a very thin layer of polyurethane foam less than 0.3mm. Water resistant: yes, but underwater, probably not. Those that are shipping now aren’t fully hermetically sealed, but the next version will be, as the lamination stack-up forms part of the battery pouch.

— Yes, they are flexible. The only issue we’re having at the moment is their thickness of 0.5mm and dissimilar materials of the stack-up causing some pulling-back of the laminates around really tight radii. But, we think we’ve solved this in the next version, targeting an overall thickness of 0.3mm and different materials.

— The battery level is something that’s included in the beacon message, and is updated once a day.

Thanks Brian! Sounds awesome.

EDIT: Found your website, ordering a few now. Can't wait for android support!

> Do they work underwater?

Bluetooth frequencies are absorbed (not sure if this is the right term) by water since the bluetooth frequency and water's resonant frequency is the same. This is why covering a bluetooth beacon with your hands drops the signal strength significantly (water in your hands absorbs most of the signal). Submerging a bluetooth device will probably significantly decrease the signals strength even if the device survives the submergence.

Do you have to re-apply the labels each year? If the battery dies, this wouldn't scale well for the labor involved to replace the labels each year?

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