Breaking News
Comments
Newest First | Oldest First | Threaded View
<<   <   Page 2 / 2
ost0
User Rank
CEO
re: GravityLight – What a GREAT idea!
ost0   1/7/2013 8:26:47 AM
NO RATINGS
Simple and Genious! :)

RWatkins
User Rank
Rookie
re: GravityLight – What a GREAT idea!
RWatkins   1/6/2013 11:02:00 PM
NO RATINGS
Well, based on the calculator at http://convert-to.com/159/energy-units.html 100 ft-lb = 135.58 J, and by my calculations a 3V LED powered by a 100% efficient generator that draws 20 mA will stay lit for 37.7 minutes. I would estimate for the 3-LED system shown with a 50% efficient power conversion system would give about 6 minutes of light per 5 foot 100 pound lift. That is some big bag to hold 100 lb. The Gravity Light web page talks about a 20-pound weight, and says 18 to 30 minutes of light output per lift. I agree something seems a little off...

Steven.Herrrick
User Rank
Rookie
re: GravityLight – What a GREAT idea!
Steven.Herrrick   1/5/2013 2:30:25 AM
NO RATINGS
Has someone done the math on this? a 20 pound bag lifted 5 feet has 100 foot-pounds of potential energy. At an efficiency of 20%, how long will a 20ma LED provide light?

Paul A. Clayton
User Rank
CEO
re: GravityLight – What a GREAT idea!
Paul A. Clayton   1/4/2013 8:29:28 PM
NO RATINGS
There was an article on this at The Register a few weeks ago: http://www.theregister.co.uk/2012/12/12/deciwatt_gravity_light/ One advantage of this device is that, other than the LEDs (I think), it is relatively low tech and could be mostly manufactured or at least assembled locally (an economic advantage, not just a hand-out but partly a hand-up) and quite possibly maintained/repaired locally. I still think that the child-powered (merry-go-round) water well pumps are a little more clever in terms of exploiting an abundant energy source and providing fun.

<<   <   Page 2 / 2


EE Life
Frankenstein's Fix, Teardowns, Sideshows, Design Contests, Reader Content & More
Max Maxfield

Creating a Vetinari Clock Using Antique Analog Meters
Max Maxfield
55 comments
As you may recall, the Mighty Hamster (a.k.a. Mike Field) graced my humble office with a visit a couple of weeks ago. (See All Hail the Mighty Hamster.) While he was here, Hamster noticed ...

EDN Staff

11 Summer Vacation Spots for Engineers
EDN Staff
11 comments
This collection of places from technology history, museums, and modern marvels is a roadmap for an engineering adventure that will take you around the world. Here are just a few spots ...

Glen Chenier

Engineers Solve Analog/Digital Problem, Invent Creative Expletives
Glen Chenier
11 comments
- An analog engineer and a digital engineer join forces, use their respective skills, and pull a few bunnies out of a hat to troubleshoot a system with which they are completely ...

Larry Desjardin

Engineers Should Study Finance: 5 Reasons Why
Larry Desjardin
45 comments
I'm a big proponent of engineers learning financial basics. Why? Because engineers are making decisions all the time, in multiple ways. Having a good financial understanding guides these ...

Flash Poll
Top Comments of the Week
Like Us on Facebook
EE Times on Twitter
EE Times Twitter Feed

Datasheets.com Parts Search

185 million searchable parts
(please enter a part number or hit search to begin)