Faraday Flashlights aka Shake Flashlights

gwenyi · Post by **gwenyi** » Fri Sep 08, 2006 8:38 am

faraday's law : an instantaneous emf will be produced when there is a rate of change of magnetic flux linkage .

Post by **VinSnr** » Fri Sep 08, 2006 8:38 am

maybe they should have this concept for cars. Considering the high fuel prices now, I don't mind doing some hand exercises by cranking the car and store some "initial power" somewhere.

I think back in the 50-60s, you need to crank the engine before you can start the car.

siahheng · Post by **siahheng** » Fri Sep 08, 2006 9:12 am

maybe they should have this concept for cars. Considering the high fuel prices now, I don't mind doing some hand exercises by cranking the car and store some "initial power" somewhere.

I think back in the 50-60s, you need to crank the engine before you can start the car

Hi, I think the cranking was to start the car which is now powered by the car battery. The new hybrid cars now can recharge and store electrical power in the batteries when the car is going downhill. Saw one the other day, noticed him becos he cut in and out of several lanes which using his signal lights - must be trying to save on battery power....

river · Post by **river** » Fri Sep 08, 2006 9:48 am

get a head light, you can wear it on your head so that you free your hand for some astro work. Extra hand in the dark is always a plus.

kingkong · Post by **kingkong** » Fri Sep 08, 2006 11:14 am

i saw one at megallan observatory near goulburn australia. the owner, me and me mrs were walking back in the dark to the house (yes, it was cloudy, drizzling in fact, like last night....). he was shaking his touchlight all the way and my petzl tikka headlight was providing light for all three...
i thought of getting one myself before that...

wAi_kiT · Post by **wAi_kiT** » Fri Sep 08, 2006 10:01 pm

Hmmm... So the most reliable one is the NightStar? Its quite ex... $51++ Anyone knows where else can I get these flashlights?

mrngbss · Post by **mrngbss** » Sat Sep 09, 2006 10:42 am

wAi_kiT wrote:Hmmm... So the most reliable one is the NightStar? Its quite ex... $51++ Anyone knows where else can I get these flashlights?

I can help you. Cost me $15-$18 per piece. I bought about 100 pieces for the school. You wind for one minute, then use for 45 mins. Nice design and very bright.

This design has three lenses in front of the LED, which helps to focus the LEDs into one single bright spot.

I've used the shake version before, but you need to shake 5 mins, use 25 min. Brightness is no fight for the winding version.

Cheers!!

rlow · Post by **rlow** » Sat Sep 09, 2006 8:46 pm

There are also battery-less torchlights (squeeze type) going for only $2.05, available from those "$2 value shop".

siahheng · Post by **siahheng** » Sat Sep 09, 2006 11:07 pm

Hmmm...So how much is it? Does it work fully on Faraday's law? And whats the brand?

Hi, the torch I bought is from "Sound-Tech" and it cost me S$31. It sounds similar to mrngbss's torch which is wound rather than shaken. Mine comes with 3 LEDs but no lens to focus the beam.

Post by **weixing** » Tue Sep 19, 2006 10:19 am

Hi,
The cloudy night got a review on one of it: http://www.cloudynights.com/item.php?item_id=1510

Have a nice day.