White LED appropriate for illumination?
in [Design]
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From: Rich Grise on Google groups on 11 Feb 2010 16:08 So, I'm going on a camping trip, and I plan to bring along some reading material for the time between sundown and the time when I get bored watching the stars and listening to the wildlife until I'm tired enough to sleep. So, I need some kind of lamp that's handier to operate than an ordinary flashlight, but will illuminate a page of print brightly enough to read "normally." And I specifically want a white LED (or LEDs), for battery life - that's another problem with an incandescent flashlight, even with fresh alkalines, notwithstanding that stupid spot - I need more of a flood, so I don't have to keep pointing the light at the passage I'm reading. I've heard tell of LED bike headlights and the like; what I want is some wide-angle "flood" light, that could illuminate an ordinary 8 1/2 x 11 page from about two feet (2/3M) away, while I'm at a normal reading distance (18-24" (1/2 - 2/3M)), brightly enough that I don't get eyestrain. Does anyone have any recommendations, or need more info? Thanks, Rich
From: David L. Jones on 11 Feb 2010 16:24 Rich Grise on Google groups wrote: > So, I'm going on a camping trip, and I plan to bring along some > reading material for > the time between sundown and the time when I get bored watching the > stars and > listening to the wildlife until I'm tired enough to sleep. > > So, I need some kind of lamp that's handier to operate than an > ordinary flashlight, > but will illuminate a page of print brightly enough to read > "normally." And I specifically > want a white LED (or LEDs), for battery life - that's another problem > with an incandescent > flashlight, even with fresh alkalines, notwithstanding that stupid > spot - I need more of > a flood, so I don't have to keep pointing the light at the passage I'm > reading. > > I've heard tell of LED bike headlights and the like; what I want is > some wide-angle > "flood" light, that could illuminate an ordinary 8 1/2 x 11 page from > about two feet > (2/3M) away, while I'm at a normal reading distance (18-24" (1/2 - > 2/3M)), brightly > enough that I don't get eyestrain. > > Does anyone have any recommendations, or need more info? > > Thanks, > Rich Get a proper book light, they are the most conveneient. I use one of these: http://www.mightybright.com/ The beam is prefectly round and even, purpose designed for reading. (I find them almost too bright with fresh batteries though) Alternatively a broad beam LED headlamp with a decent low power mode. Dave. -- --------------------------------------------- Check out my Electronics Engineering Video Blog & Podcast: http://www.eevblog.com
From: Ban on 11 Feb 2010 16:25 "Rich Grise on Google groups" <richardgrise(a)yahoo.com> schrieb im Newsbeitrag news:58c8de2d-d513-4b2d-9130-28c4bc047c59(a)e19g2000prn.googlegroups.com... > So, I'm going on a camping trip, and I plan to bring along some > reading material for > the time between sundown and the time when I get bored watching the > stars and > listening to the wildlife until I'm tired enough to sleep. > > So, I need some kind of lamp that's handier to operate than an > ordinary flashlight, > but will illuminate a page of print brightly enough to read > "normally." And I specifically > want a white LED (or LEDs), for battery life - that's another problem > with an incandescent > flashlight, even with fresh alkalines, notwithstanding that stupid > spot - I need more of > a flood, so I don't have to keep pointing the light at the passage I'm > reading. > > I've heard tell of LED bike headlights and the like; what I want is > some wide-angle > "flood" light, that could illuminate an ordinary 8 1/2 x 11 page from > about two feet > (2/3M) away, while I'm at a normal reading distance (18-24" (1/2 - > 2/3M)), brightly > enough that I don't get eyestrain. > > Does anyone have any recommendations, or need more info? > There are these flourescent small tubes 5W for camping use, they are more bright and need less power than LEDs and cost less.
From: David Drinnan on 11 Feb 2010 16:35 On Feb 11, 3:08 pm, Rich Grise on Google groups <richardgr...(a)yahoo.com> wrote: > So, I need some kind of lamp that's handier to operate than an > ordinary flashlight, > but will illuminate a page of print brightly enough to read > "normally." And I specifically > want a white LED (or LEDs), for battery life - that's another problem > with an incandescent > flashlight, even with fresh alkalines, notwithstanding that stupid > spot - I need more of > a flood, so I don't have to keep pointing the light at the passage I'm > reading. I bought one of these book-lights on a whim one day http://www.amazon.com/Reading-Light-Energizer-Trim-Lithium/dp/B000GOYMAE/ref=sr_1_1?ie=UTF8&s=hi&qid=1265923696&sr=8-1 because I thought it would be better than the lamp I was using when I'm reading in bed after my girlfriend has fallen asleep. The thing is so bright that she tells me to use the lamp instead. So it ought to do well for you. Though part of her complaint with the book-light is that the white light isn't as warm as the lamp's. Can't say how sturdy or long-lasting the book-light is, though, since... I use the lamp instead.
From: pimpom on 11 Feb 2010 16:53
Rich Grise on Google groups wrote: > So, I'm going on a camping trip, and I plan to bring along some > reading material for > the time between sundown and the time when I get bored watching > the > stars and > listening to the wildlife until I'm tired enough to sleep. > > So, I need some kind of lamp that's handier to operate than an > ordinary flashlight, > but will illuminate a page of print brightly enough to read > "normally." And I specifically > want a white LED (or LEDs), for battery life - that's another > problem > with an incandescent > flashlight, even with fresh alkalines, notwithstanding that > stupid > spot - I need more of > a flood, so I don't have to keep pointing the light at the > passage I'm > reading. > > I've heard tell of LED bike headlights and the like; what I > want is > some wide-angle > "flood" light, that could illuminate an ordinary 8 1/2 x 11 > page from > about two feet > (2/3M) away, while I'm at a normal reading distance (18-24" > (1/2 - > 2/3M)), brightly > enough that I don't get eyestrain. > > Does anyone have any recommendations, or need more info? > > Thanks, > Rich I don't know what's available where you are, but over here in India, there's plenty to choose from, mostly Indian and Chinese products. Too numerous to describe. Some have a dozen LEDs in a small table lamp type frame using AA cells at under $1 US. Some have 200+ LEDs in a 360-degree lantern type configuration with a built-in rechargeable battery for ~$50. Some come as direct replacements for mains incandescent bulbs with 10-100 LEDs, but run from rechargeable batteries in emergency light mode (~$3-10). Some have remote controls. Most of the ones I've seen except the flashlight types will meet the lighting angle you need. These are just a few examples of what we get here. I'd think'd be available almost everywhere else. |