3 ms·

This was a huge turn-off for wearables like the the Oura ring. When you do metal work, you take off rings because if a bead of molten metal gets on your very co

This was a huge turn-off for wearables like the the Oura ring. When you do metal work, you take off rings because if a bead of molten metal gets on your very conductive gold ring, you won't be able to get it off, and it's a quick way to get a second-degree burn. Also, "degloving." My fear with these rings is if the battery goes, it's burn time. I can't find enough specs to know if the battery holds enough energy to do this, but my fingers are worth too much to me to take this chance. Edit: the battery is .0777 Wh. If that burnt up in 10 seconds, that'd be 30 W concentrated on a square cm of skin, then distributed around the ring. I think that's a burn?

londons_explore 5y ago
It's a burn, but not a very bad one.
- L_226 5y ago
  that's 300 Joules, a typical .22 long rifle round delivers about 180 J
  - londons_explore 5y ago
    Cycling on a gym bike for 1 second is also 300 Joules... It all depends how it's delivered!
    - L_226 5y ago
      So IEEE 1584 actually defines the boundary for second degree burns to unprotected skin at > 5.0 J/cm^2 [0]. Assuming the parent comment parameters of 0.0777 Wh discharging thermally over 10 seconds into ~1cm^2 of finger, that is ~27 joules per cm^2 per second for 10 seconds. I think you would probably lose the finger. Please correct me if I am wrong. [0] https://en.wikipedia.org/wiki/Arc_flash#Distance https://en.wikipedia.org/wiki/Arc_flash#Distance
13of40 5y ago
A few years back I had a Samsung smart watch, and one day I was sitting at my desk and started to feel an uncomfortable burning feeling from it. It managed to give me a little first degree burn on my wrist before I got it off. I rebooted it, and shortly afterwards it did it again, so it's been sitting in a drawer ever since. The only thing close to an explanation I found online was that if it needs to do something intensive like sync 100 SMS messages it can overheat. TBH, though, I think walking around with a cell phone in my front pocket all day is more of a risk.

londons_explore 5y ago

It's a burn, but not a very bad one.

L_226 5y ago
that's 300 Joules, a typical .22 long rifle round delivers about 180 J
- londons_explore 5y ago
  Cycling on a gym bike for 1 second is also 300 Joules... It all depends how it's delivered!
  - L_226 5y ago
    So IEEE 1584 actually defines the boundary for second degree burns to unprotected skin at > 5.0 J/cm^2 [0]. Assuming the parent comment parameters of 0.0777 Wh discharging thermally over 10 seconds into ~1cm^2 of finger, that is ~27 joules per cm^2 per second for 10 seconds. I think you would probably lose the finger. Please correct me if I am wrong. [0] https://en.wikipedia.org/wiki/Arc_flash#Distance https://en.wikipedia.org/wiki/Arc_flash#Distance

13of40 5y ago

A few years back I had a Samsung smart watch, and one day I was sitting at my desk and started to feel an uncomfortable burning feeling from it. It managed to give me a little first degree burn on my wrist before I got it off. I rebooted it, and shortly afterwards it did it again, so it's been sitting in a drawer ever since. The only thing close to an explanation I found online was that if it needs to do something intensive like sync 100 SMS messages it can overheat. TBH, though, I think walking around with a cell phone in my front pocket all day is more of a risk.