LED lighting tutorials?

[ilyafish]

Hey guys,

I have taken some interest in looking into creating my own LED lights and using them throughout the coach....can any of you guide me to some online tutorials that would basically take someone from having absolutely no knowledge of LEDs and not too much knowledge in anything electrical with the exception of the common basics, to being able to build and install an entire LED lighting system in a coach.

thanks!

-ilya

[boogiethecat]

Start here
http://www.theledlight.com/ledcircuits.html

It's very basic.  Note that it purposely mis-informs you of what is really happening by avoiding the word "current" as much as possible, because dealing with current electronically seems to be beyond even some savvy people ( ignoring voltage and controlling things by current is a hard concept to grasp for many).
Instead the writer explains it all in terms of voltage which most people do understand.  So although what they have to say isn't quite technically spot-on, it's done that way on purpose and in getting around it they've done a very excellent job of simplifying things enough so you can properly design LED systems without grasping the total tech of it.

Have fun

[ilyafish]

Thanks for the link!  Alot simpler than i thought :-)

[vaunter]

ive ben messing with leds alot lately for my bus
make sure you get the clear white not the blue tint leds....hart to tell from most sites what they are selling
allso when if you are playing with the led`s look into the lm317 varriable volt/amp regulators and some real nice in expencive 2k 25 turn turnpots instead of resistors ...that will make your life a lot easier

i plan on doing up some super simple to follow diagrams (how toos) for building 12v and 24v led lights and on extreemly inexpencive volt and amp monitors for 12v 24v and 110v with digital display.....how cheap....about $3

[WEC4104]

This is a pretty broad question, so I'll fire off a few assorted details, but I'll only be scratching the surface. I'll also limit this to a discussion of LED lights for interior use, and leave the LED taillights to another discussion.

I have messed around with building a few LED lights and currently use them in my bus. They have several key advantages that make them well suited for a bus conversion. First and foremost, they are very efficient and use very little power.  They also produce next to no heat, so they place no load on the cooling system. Lastly, they are rugged, have a very long lifetime, and handle voltage fluctuations pretty well. On the downside,  some of the higher output units can be a little pricey, and your would need many LEDs to match the light output of say, one halogen puck light.

I think LEDs are well suited to some, but not all, bus lighting needs.  I personally find that a mix of LED lights supplimented by other lighting, strikes an ideal compromise.

If you want to creat your own LED lights, so have several options.  You can buy ready-made "LED bulbs" that plug into regular 12VDC fixtures.  The unit is shaped like a regular automotive style bulb, but has several LEDs attached to the base.  

Or, you can buy a bag of LEDs and start building your own.  LEDs come in various colors, with the white ones used for many general lighting purposes.  Be aware that most white LEDs give off a very "cold" wavelength of light.  Unlike incandescent bulbs that have a warm slightly yellowish tint, most white LEDs lean toward the blueish-white.  To my eye, it looks very much like moonlight.  

Many discrete LEDs are designed for a voltage somewhere between 3 and 5 volts.  So if you are running your lights off of a 12V house battery system you need to take that into account.  This is typically done by putting a proper value resistor in place, or putting multiple LEDs in series, or both.

One of my favorite LED projects in my bus is my bathroom night light.  I always had a 12 volt fixture on the bathroom ceiling that was very bright.  In fact, too bright for those middle of the night excursions.  One day, I took it down from the ceiling and drilled two small holes into the plastic lens.  One hole was for a second on/off switch, and the other was a smaller hole just big enough to hold a single white LED.  I did a little creative wiring and remounted the fixture. At night, before going to bed I turn on the little LED. It stays on all night long (using negligible electricity).  If I, or one of the kids, gets up in the middle of the night to use the bathroom, it is just the right amount of light to see what you are doing, without being overpowering. Works great.  

Another link to check out ... http://www.superbrightleds.com/led_prods.htm

[Jeremy]

Given that there seems to be an almost infinite number of led 'bulb replacement' variants available nowadays to fit every type of standard light fitting (both domestic and automotive) I'm curious as to why anyone would consider building their own from scratch? Unless it is simply for the fun of the project, which I can understand.

I haven't done much with led lighting yet myself, but do intend to, so would be interested to know what people consider to be the failings of the plug-in bulb-replacement sort.

I did see something which was new to me just the other day - a plug-in replacement for a standard puck light bulb which contained a tiny flourescent tube rather than leds - was supposed to be brighter than leds yet still very low current consumption

Jeremy

[vaunter]

because leds are pennies ea and you can build to fit your desire

[Jeremy]

Ok........but the type of puck bulb replacements for instance that I'm thinking of can be bought for a couple of pounds each (say $3.00 each, no doubt less if you're buying lots). I realise the cost of the leds inside is only a fraction of this, but what's your time worth trying to reproduce what is a mass-produced item?

I realise there may be some situations where you cannot buy an off-the-shelf bulb that will do the job, but given the huge number of variants available now I would think you've got to try pretty hard to have no option other than making your own. No doubt some of more unusual types do cost a lot more that a few dollars each though

Jeremy

[LegalEagle82]

this question made me think of all the LED xmas lights we bought this year.  I would love to cut off few lights and run them on my 12 volt interior lights.  how possible is that.  a few well directed dash lights would be nice.  what is the result if cutting off the 110 plug and power up the line with 12 volts.     the xmas lights have some type if in line resistor etc.  the lights come down in a week!

[boogiethecat]

Christmas Led lights are usually wired together in a way that can't be modified, that pretty much only runs on 120 volts.  They put so many lamps in series that it's impractical to try using them on 12 volts.

That said, if you buy a string and figure out how many leds are actually in series, then cut 1/10 of that number off, you could probably use that 1/10 long strip on 12 volts with a properly calculated resistor in series with the short string.  You have to be careful 'cause often they create multiple series blocks and tie them together in creative ways.... just make sure you've traced them out correctly.  Ok, if you didn't: poof...no big deal though cause they're cheap, right? 

Another approach is to just plug your leds into 120 volts using a cheap 12v inverter.  On ebay you can get Vector 70 watt inverters for 10-15 bucks with shipping  (ie Item number: 110328284329)
or 75 watt ones for $15 (search "75 inverter").  They are so cheap that they can be considered throwaways, and though they are cheep square wave units, they work great for led strings. I use lots of them this way at Burning man.

[Lin]

This started me thinking (obviously not a good sign).  I currently have some lighting valences with simple, plug-in fluorescent fixtures behind them.  They work, but it is a very dated effect.  I was wondering about trying strings of LED's instead.  As "tis the season" there are strings of white LED's available dirt cheap and I could see how I liked the effect with a simple plug-out, plug-in installation.  One question though is how many 10mm LED's would in take to replace a two foot florescent? 

By the way, thanks to the spellchecker, I have used two different correct spellings of the same word.  Gee, Mr. Wizard...!

[Jeremy]

By the way, thanks to the spellchecker, I have used two different correct spellings of the same word.  Gee, Mr. Wizard...!

Different words, apparently. Thefreedictionary.com says that florescent / florescence means "A condition, time, or period of flowering, from the Latin 'florscentia'" whereas 'flourescent' in this context is defined as "emitting light during exposure to radiation from an external source".

Another similar example is silicon and silicone - often interchanged but actually mean completely different things.

As you've guessed by now, I do have a bit of an interest in language.

Jeremy

[Lin]

Thanks you for the correction.  As one who is spelling challenged to begin with, I may not apply them properly in the future, but at least I will know that I have a 50% chance of being right/wrong.  So which is correct fluorescent bulb or florescent bulb and how many LED's equal the light of a two foot one?

[Rick Brown]

The amount of light a device produces is often specified in lumen.  An American 100 Watt bulb produces about 1700 lumen.  The brightness of leds is usually specified in candela/1000 or mcd with an associated viewing angle.  You can calculate lumen from candela and viewing angle at http://led.linear1.org/lumen.wiz and thus compare devices if you choose to build your own.
The best I've found thus far is at http://lc-led.com/View/itemNumber/328.  That comes in at about 40 lumen/watt compared to 17 lumen/watt for the 100 watt bulb.  I haven't bought this yet (but plan to) and so am not endorsing it.
-RickBrown in Reno, NV

[Jeremy]

John

'Fluorescent' is correct when taking about bulbs. Please don't think my earlier post was trying to be clever or critical by the way - I was just interested in a word I hadn't seen before so I looked it up.

Regarding how many leds you would need to replace a two foot fluorescent tube, that is of course a 'length of string' question because leds vary wildly in terms of size and power - for instance, Lexus now has a model with led headlights, which are obviously hugely powerful. I would think you would need quite a few of the Christmas tree sort to get an equivalent amount of light to the fluorescent, but if as you say the existing light is behind a valance it might be more for 'effect' anyway, and so it is perhaps less critical. Why not experiment by sticking a set of Christmas tree lights there temporarily and seeing what happens?

Jeremy