what i've been up to, two

[willib]

Hi pepa , i got both 'ends' off , now i have two threaded shafts , one side has threads to mount the blades , i think i'll put the bolts back in attached to a chain and drop/though it down , if that dosnt work i'll try what you sugested and if that dosnt work there is allways the bottle jack just waiting to be built into a press.

[hiker]

hey willib......

watch you workin on..ceiling fan mod??

heres some info you might be interested in--i was watching the news a few days ago..

seems the army needs some help..each one of their soldgers packs around a ton of spare batteries for there electronics..so they have some contest going on to help on reducing

all that weight..they say what ever you come up with cant weigh over 9 pounds and has

to make at least 20 watts-they didnt mention at what voltage ..

seems like an easy celing fan coversion could work--hand powered..geared up??

or even a small dc motor.......i take it they want a battery charger of some sort.

thats all the info i have--dont no what the prize is--or even where to sign up for it..

i belive the contest starts next month...maybe someone else on the board could help out

with some more info...........

 

[RP]

Here's a link to the story.

http://www.cnn.com/2007/TECH/07/16/wearable.power.prize/index.html?iref=newssearch

[pepa]

it should work for you as i did two more today. thinking about ganging several together when i get time to play with them. pepa.

[hiker]

are you going to use on length of pipe with mags inside to power up that monster??

[hiker]

thanks for the link RP.........

[pepa]

i will make a post on this a little later, pepa.

[willib]

They don't say if the soldier needs to power/crank  the unit himself...

20 Watts average power for four days at 8.8 lbs with no input ,hmmm

my mini gen isnt too heavy , but it would need to be turned/cranked by somone..

[Capt Slog]

I once saw a "Jungle Genny" at a steam fair.  This was a smallish suitcase metal box which I contained a steamturbine generator.  They were apparently dropped with troops into Borneo during WW2.  If I remember rightly, it sort of folded out of the case; I never saw it running, it was display only and in pristine condition.

I remember wondering at the time what sort of noise it must have made.  It can't have been very popular with soldiers trying to keep their position secret and doesn't seem to have been a huge success because that is the only one I've ever seen or heard of.

I doubt it came under the 9lb limit, but it shows there's nothing new!

[vawtman]

Hmmm

 Now if one could use their normal walking motions to spin something.

 Just a crazy thought.

[willib]

it wouldn't have to spin..

a while ago i built a linear alternator , still have it ..

picture coils wound around a tube with magnets inside the plastic tube, it was origionally a super shaker alternator , i believe it produed over 300 mA , just by shaking it , the copper and tube weigh just under 2 lbs.

so 4 lbs on each leg could concieveably pulse an amp per step , with larger mags ..

[scottsAI]

Hi RP,

Very interesting!

20 watts * 96hr = 1,920 watt-hours.

The best Lithium ion polymer battery

http://en.wikipedia.org/wiki/Lithium_polymer_cell

Energy/weight 130-200 Wh/kg

10. kg to meet the requirements.
    
22. lb is 2.5x larger than the 8.8lb target weight.
    
    

A good example for conversation, reducing the power needed...

If half the weight is battery 2 * 200 = 400 Wh, just shy of 1 days power.

The other 2kg would need to produce the 1500Wh over the 4 days.

Using solders movements to generate 1.5kWh is possible.

Fuel cell looks like a possible solution, Searching:

http://news.softpedia.com/news/Fuel-Cell-Power-Source-with-Twice-the-Energy-Density-of-Lithium-Batte
ries-6787.shtml

energy density--about 450 watt-hours per kilogram

Very close not quite the 2.5x needed.

Most interesting link:

http://www.media.mit.edu/resenv/pubs/books/Starner-Paradiso-CRC.1.452.pdf

Basically petal power or power extracted from walking can produce 60w, requires 8 hr/day to make it work.

A Human can generate a lot of power beyond 1hp for a time. A long distance runner 900w/hr.

Have fun,

Scott.

[richhagen]

The PDF lists a bit on the requirements although it still seems a bit vague to me.  An incomplete summary:

Dual voltage, 14 and 28 volts

three and a half days of bench testing (discharge) with a varied temperature and discharge profile, with 200 Watts for five minutes being the largest power draw, and an average power draw of 20 Watts over that period.

after the bench testing, and without recharging/refueling, the unit goes through a half day of field testing

The lightest unit under 4kg that survives gets the prize.  

Rich

[hiker]

what about somthing like a handwarmer -with a thermocoupler to prouduce power..

could be diesiel powered--less danger of fire if hit by a bullet ........