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> Does it get warm? > Brian S (Creator): Nope not at all. LED's do not emit much heat and the Titanium body of the eye offers great heat shielding from any hea

by flak48 4y ago

> Does it get warm? > Brian S (Creator): Nope not at all. LED's do not emit much heat and the Titanium body of the eye offers great heat shielding from any heat emitted. [https://www.tiktok.com/@bsmachinist/video/7132678375411584302?is_from_webapp=v1&item_id=7132678375411584302 https://www.tiktok.com/@bsmachinist/video/713267837541158430...]

deleted 4y ago
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dymk 4y ago
LEDs of a couple of watts do emit a noticeable amount of heat. Being titanium doesn’t mean anything - here the heat has to go somewhere eventually. Either out of the front of the eye where it’s “uninsulated” or it’ll get hot enough internally that the body will get warm.
- hamburglar 4y ago
  Being titanium means it acts as a heat spreader and a buffer that can absorb and dissipate the small bursts of heat you might expect from brief flashlight use. Rather than the LED touching one spot in your eye socket (which would probably be a noticeable amount of heat even if not uncomfortable), the heat is spread over the entire titanium body.
  - spookthesunset 4y ago
    Given the size of the battery I’d assume you could only pump out “max power” for a short time anyway. If that titanium does act as a buffer, things might be good. Honestly the heat thing was the first I thought of too. It would nice if the dude goes into more detail about it because I’m sure it is one of the top questions asked.
- xeromal 4y ago
  > Being titanium doesn’t mean anything This is a pretty confident answer, but I think you miss the point of the titanium. It can act as a heat battery and slowly let it dissipate all around vs a focused point of heat.
  - kragen 4y ago
    Titanium has much less thermal mass than the same volume of water. Water is 4.2 J/g/K and 1 g/cc, thus 4.2 J/cc/K. https://en.wikipedia.org/wiki/Titanium https://en.wikipedia.org/wiki/Titanium is 25.060 J/mol/K, 4.506 g/cc, and 47.867 g/mol, so 0.5235 J/g/K and 2.359 J/cc/K. I think water is also a better thermal insulator if you can keep it from convecting, and a better heat spreader (to eliminate "a focused point of heat", which I agree is a problem) if you do let it convect. But that's the opposite of titanium being a good heat shield.
    - xeromal 4y ago
      Thanks for commenting. I'm a layman here so providing hard numbers helps me wrap my head around the comparison. I think you're saying that water is roughly double a better thermal insulator? I wonder if the man could devise a water layer around what generates the heat in order to reduce the chance for burning his body? He probably has to weigh the chance for water to mix with the components vs a simple titanium hunk of metal. I guess that's what materials engineers are for?
      - kragen 4y ago
        I'm a layman too. No, I didn't provide numbers on thermal conductivity, just specific heat, though it is now unfashionable to call it that. Yes, putting some water inside the titanium would increase the thermal mass of the overall assemblage, and I don't know of anything that would work better than water for this. This would reduce the temperature to which the eye-socket tissue is heated by intermittent but high-intensity LED usage, reducing the risk of burns, because it smooths it out over time. If the LED is not at the top of the eye, or if the eye rotates, liquid water would also help to smooth it out over space. However, to minimize the temperature to which the eye-socket tissue is heated, it would also be beneficial to interpose thermal insulation between the tissue and the heat source, such as a thick layer of teflon around the outside of the eyeball (or saline-solution-soaked teflon foam). This will slow heat transfer from the hot eyeball to the eye-socket tissue, giving blood flow more time to convect away the waste heat and thus producing a lower temperature in the sensitive tissue. I think the more important issue here is that he's using low enough power with a low enough duty cycle that it isn't much of a problem.

by flak48 4y ago

deleted 4y ago

[deleted]

dymk 4y ago

LEDs of a couple of watts do emit a noticeable amount of heat. Being titanium doesn’t mean anything - here the heat has to go somewhere eventually. Either out of the front of the eye where it’s “uninsulated” or it’ll get hot enough internally that the body will get warm.

hamburglar 4y ago
Being titanium means it acts as a heat spreader and a buffer that can absorb and dissipate the small bursts of heat you might expect from brief flashlight use. Rather than the LED touching one spot in your eye socket (which would probably be a noticeable amount of heat even if not uncomfortable), the heat is spread over the entire titanium body.
- spookthesunset 4y ago
  Given the size of the battery I’d assume you could only pump out “max power” for a short time anyway. If that titanium does act as a buffer, things might be good. Honestly the heat thing was the first I thought of too. It would nice if the dude goes into more detail about it because I’m sure it is one of the top questions asked.
xeromal 4y ago
> Being titanium doesn’t mean anything This is a pretty confident answer, but I think you miss the point of the titanium. It can act as a heat battery and slowly let it dissipate all around vs a focused point of heat.
- kragen 4y ago
  Titanium has much less thermal mass than the same volume of water. Water is 4.2 J/g/K and 1 g/cc, thus 4.2 J/cc/K. https://en.wikipedia.org/wiki/Titanium https://en.wikipedia.org/wiki/Titanium is 25.060 J/mol/K, 4.506 g/cc, and 47.867 g/mol, so 0.5235 J/g/K and 2.359 J/cc/K. I think water is also a better thermal insulator if you can keep it from convecting, and a better heat spreader (to eliminate "a focused point of heat", which I agree is a problem) if you do let it convect. But that's the opposite of titanium being a good heat shield.
  - xeromal 4y ago
    Thanks for commenting. I'm a layman here so providing hard numbers helps me wrap my head around the comparison. I think you're saying that water is roughly double a better thermal insulator? I wonder if the man could devise a water layer around what generates the heat in order to reduce the chance for burning his body? He probably has to weigh the chance for water to mix with the components vs a simple titanium hunk of metal. I guess that's what materials engineers are for?
    - kragen 4y ago
      I'm a layman too. No, I didn't provide numbers on thermal conductivity, just specific heat, though it is now unfashionable to call it that. Yes, putting some water inside the titanium would increase the thermal mass of the overall assemblage, and I don't know of anything that would work better than water for this. This would reduce the temperature to which the eye-socket tissue is heated by intermittent but high-intensity LED usage, reducing the risk of burns, because it smooths it out over time. If the LED is not at the top of the eye, or if the eye rotates, liquid water would also help to smooth it out over space. However, to minimize the temperature to which the eye-socket tissue is heated, it would also be beneficial to interpose thermal insulation between the tissue and the heat source, such as a thick layer of teflon around the outside of the eyeball (or saline-solution-soaked teflon foam). This will slow heat transfer from the hot eyeball to the eye-socket tissue, giving blood flow more time to convect away the waste heat and thus producing a lower temperature in the sensitive tissue. I think the more important issue here is that he's using low enough power with a low enough duty cycle that it isn't much of a problem.