Body-heat powered flashlight

[880arm]

You can count me in. Whether or not it turns into a viable product, I commend her efforts.

 

[phoneguy]

" Bright" little girl there !!!

Bryan

 

[RetroTechie]

The concept of using thermal body heat to power a flashlight is not new, but the embodiment with interior metal tube insulated from the hand with one contact point for the hot side is interesting. That provides a thermal mass for the cold side that makes the concept work. It would be interesting to see at how high an ambient temp it does work. They discuss 5 and 10C, but not warmer. The article said that it provided steady light for 20 minutes. I wonder if this was the limit of the test or that was the point at which the interior tube became too warm for the system to function?

No, the concept as far as I understood it, is centered around "hollow".

You have your hand, wamer than ambient temperature. Temp difference will generate heat flow. Take hollow tube, and it will provide an easy pathway for heat to flow (cooling by air passively flowing through the tube). Put a Peltier in between -> electricity.

So it works forever as long as you're warmer than surrounding air. Energy output is very small (mW range), but enough to make a LED light up.

Mostly liked her methodical approach. Got an idea in her head, 'simply' worked out what would be needed, did the math and found that it should be possible. Worked out the details, built it, and indeed it worked. More engineering than science, really. Obviously a smart girl, that methodical approach should let her go far I hope. I bow to my fellow nerd. :bow:

For easy to remember: the thing to Google for is "hollow flashlight"

 

[Brave Little Toaster]

Maybe in a hundred or so years we'll have fabric with that fancy material that captures our heat to power electronics

 

[radioactive_man]

NASA uses something similar on deep space probes: Peltier elements around a rod of plutonium. One side of the Peltier elements is exposed to the warmth (due to spontaneous fission) of the plutonium rod, the other side is exposed to the cold of deep space.

I propose to upgrade her light by sticking a plutonium rod in it. What could possibly go wrong? Now excuse me, while I go patent my idea.

...

What?

 

[RoBeacon]

I want one.


Sent from my iPhone using Tapatalk

 

[RetroTechie]

Me too! The nuclear powered one, that is.

+ Safe as long as you don't grind it in half, or dissolve in acids & drink that
+ Good lumens output
+ Runtime measured in decades
+ No batteries needed
+ Also good as a handwarmer
- Bulky/heavy (and thus, no good as EDC)
- Expensive
- Customs might be fussy about shipping one
- Not good to keep in your pants pocket
- In hot weather, makes you sweat even harder
- Power source keeps being depleted 24/7, regardless of the on/off switch (if present)

 

[matlocc]

what do you guys think about this kid?

http://news.yahoo.com/blogs/this-co...hlight-could-change-world-182121097.html?vp=1

 

[silentlurker]

Re: what do you guys think about this kid?

Probably won't rival the brightest of the bright, but there are obviously tons of applications for this kind of light. Bravo!

 

[easilyled]

Re: what do you guys think about this kid?

Amazing and it can probably be tweaked to produce greater output.
Imagine how useful it would be if trapped underground (or in a cave, for instance).
The girl is a genius.

 

[carrot]

Re: what do you guys think about this kid?

This would be really cool in headlamp form!

 

[parnass]

Re: what do you guys think about this kid?

Bravo. Wonder to what extent her flashlight cools your hand at the same time it is absorbing heat.

 

[StorminMatt]

Re: what do you guys think about this kid?

Given that thermoelectrics require a good heat sink in which to dissipate heat, I wonder how long the light will run before it becomes 'heat soaked'. I would imagine that performance will probably suffer in warmer weather. On the other hand, this light could become a whole lot more viable with the development of more efficient thermoelectric materials.

 

[Lampbeam]

Re: what do you guys think about this kid?

A damp spongy sleeve could be used around the outside as an evaporator in hot dry climates. It wouldn't take much water. Maybe a solar panel to give it a boost. The possibilities are interesting. She deserves the recognition. It could help a lot of people.

 

[Mr. Tone]

Re: what do you guys think about this kid?

That is cool and impressive. There is definitely a lot of potential for this. Bravo to her for being the first on record to think of this and bring it to fruition!

 

[callmaster]

Re: what do you guys think about this kid?

She is certainly changing the world. Good for her, too bad about the output though but pretty decent for everyday application I think. You never know what could be tweaked though. The human body is rather err mysterious.

 

[JulianP]

We should send this girl a CPF "recognition of achievement certificate" and offer to buy lights from her if she ever needs some funding. We'll have to weed out demands for titanium and trits, though...

I would be careful about this. She might end up a full flashaholic and spend all her scholaship money on Polarions, Maelstroms XM18s, Titanium mods, Maxabeams etc etc. "I...need..more...lumens..."

 

[oKtosiTe]

 

[moozooh]

One side of the Peltier elements is exposed to the warmth (due to spontaneous fission) of the plutonium rod, the other side is exposed to the cold of deep space.

Wait, that actually works? Do you have a link on hand or something?

I mean deep space cold isn't like your typical Arctic cold. It's more like vacuum, where free-flowing particles aren't remotely abundant enough to carry the heat away efficiently like, say, air does it. I would expect the elements to overheat eventually, if not instantly. What am I missing?

 

[RetroTechie]

Heat transfer happens by:

1. Conduction (also through solid materials)
2. Flow (like how hot air rises up & takes heat with it)
3. Radiation (works equally fine in a vacuum) <- what you're missing