Lightbox? Teach me about LED's.

[walker]

So I want to build a 'lightbox'.  I saw one for sale on craigslist once.  Just an enclosure with a bunch of LED's on it, and a power jack.    I'd like to use an acrylic enclosure, a boss style 9v,  a rocker switch for power (or maybe a stomp switch), and a crapload of LED's.  The point would be to stick it under the riser on my pedal board and illuminate things.   

I guess along the lines of this: http://www.diystompboxes.com/smfforum/index.php?topic=80078.0  but much smaller.

Now my questions, after playing abound on my breadboard and frying some LED's (they smell nasty!).  A found that with LED's in parallel only the first one lit up, so they should be in series?   Does each LED need it's own resistor, or would one right out front suffice?  I know different colors need different resistance to be the same brightness, but I'm not worried about that.   To maximize brightness, what is the lowest value resistor I can use and not fry the LED's?  What color LED's would be best?  Can I just mix and match whatever odd sized LED's I find at RadioShack? 


Oh, brainstorm as I type... what if I used one power source, then wired a bunch of switches so that switch 1 would turn on a bunch of blue lights, switch 2 would turn on a bunch of red lights, switch 3 greens, etc.  Then I could mix different colors together etc.   Or use an LFO to make them switch randomly?   

[MikeH]

Check it:

http://led.linear1.org/led.wiz

[amptramp]

If you fry gallium arsenide LEDs and they smell nasty, that may be because you are inhaling arsenic or its oxide.  Arsenic is toxic (everybody knows that), cumulative (many people know that) and addictive (some people know that).  Don't make a habit of it.

[Taylor]

It's a bummer to be addicted to arsenic, since you'd be craving something, but have no idea what.

On a serious note, though, I did not realize that frying LEDs held such grave consequences. This should be made more well known. Are most LEDs gallium arsenide?

Edit: found this:

http://en.wikipedia.org/wiki/Led#Colors_and_materials

No arsenic in blue LEDs, but I'm not sure the toxicity of the other elements in there.

[phector2004]

If you fry gallium arsenide LEDs and they smell nasty, that may be because you are inhaling arsenic or its oxide.  Arsenic is toxic (everybody knows that), cumulative (many people know that) and addictive (some people know that).  Don't make a habit of it.

mmm... don't think so.

its not good for you, but it'll take a ton of arsenic to kill someone or even make you dependent. back in the age of enlightenment and the renaissance, people would be feeding tons of it to their enemies over weeks. breathing in LED smoke will at most damage a few thousand cells, but considering the sheer number of cells that make us up, if you want to be health conscious, you're better off worrying about more important things like cardio!

as for the LEDs, you only need one resistor if they're in series, but don't burn one out or theyre all gone! (think of it as when you hook up the christmas lights and they dont seem to work!)

[R.G.]

The temperatures needed to dissociate arsenic from gallium arsenide are far higher than the temperatures to boil and oxidize the thermoplastic lens/package. The organics in the plastic vapor and combustion products are nasty smelling enough, and probably mildly toxic. But I doubt there is much arsenic in the air from frying an LED.

[walker]

Haha, this isn't the direction I saw this thread going... but it sure is amusing!   So, deadly or not, a few thousand cells, or whatever... I won't make a habit of it.   Actually, I've been told that inhaling fumes from soldering is also pretty bad so I've thought about wearing one of those surgical masks while working with any electronics.   

Mike H thanks for that link, it was really helpful.  I read through most of that website, then went to radioshack for a pile of LEDs to play with.  Also found some acrylic boxes online, though designed more for bathroom nic nacks then electronics.    Anyone know a good source for acrylic enclosures?

So my idea for multiple switches controlling different colors.... anyone have a clue how I'd wire that?  I'm hoping somebody will see this thread that has tried something like this before. 

[MikeH]

Haha, this isn't the direction I saw this thread going... but it sure is amusing!   So, deadly or not, a few thousand cells, or whatever... I won't make a habit of it.   Actually, I've been told that inhaling fumes from soldering is also pretty bad so I've thought about wearing one of those surgical masks while working with any electronics.   

Mike H thanks for that link, it was really helpful.  I read through most of that website, then went to radioshack for a pile of LEDs to play with.  Also found some acrylic boxes online, though designed more for bathroom nic nacks then electronics.    Anyone know a good source for acrylic enclosures?

So my idea for multiple switches controlling different colors.... anyone have a clue how I'd wire that?  I'm hoping somebody will see this thread that has tried something like this before. 

Most folks here don't use acrylic enclosures because of their lack of shielding (which causes audio circuits to be noisy) and their lack of strength for stomping purposes.  I think hammond makes some nice ones, but they wont be cheap.

If you want to have a different switch for each color just work up a layout (using the link above) for each color.  Where you see the +voltage on each diagram you have a switch.  And the other side of each switch all connect together at the DC jack +.  Tie all of the grounds together and connect them to the ground on the DC jack.  Really you have several different circuits all sharing the same power source.

[alparent]

Inhaling smoke from burning LEDs and soldering is bad? No wonder I'm hooked!

I'm trying to quite but I don't have the will power......
I need some help..........
Maybe if I wrapped solder around my arm a couple of time that would help with the urges?



Sorry! Going back to my hole now.

[Skruffyhound]

A surgical mask won't help you much against the fumes, but it may help you to re-breathe the water vapour from your exhalations and slowly fill your lungs with water. Dust masks without valves should only be worn for max 20 minutes before taking a break of at least five minutes to clear some water out. That's what health and safety tell us here in Denmark.

[amptramp]

If you fry gallium arsenide LEDs and they smell nasty, that may be because you are inhaling arsenic or its oxide.  Arsenic is toxic (everybody knows that), cumulative (many people know that) and addictive (some people know that).  Don't make a habit of it.

mmm... don't think so.

its not good for you, but it'll take a ton of arsenic to kill someone or even make you dependent. back in the age of enlightenment and the renaissance, people would be feeding tons of it to their enemies over weeks. breathing in LED smoke will at most damage a few thousand cells, but considering the sheer number of cells that make us up, if you want to be health conscious, you're better off worrying about more important things like cardio!

as for the LEDs, you only need one resistor if they're in series, but don't burn one out or theyre all gone! (think of it as when you hook up the christmas lights and they dont seem to work!)

Even in recent history, some Yugoslavians living in the mountains near the Adriatic Sea deliberately consumed arsenic.  It works as a blood thinner that increases weight, strength and stamina, enabling people to carry heavy loads in the mountains.  It keeps the skin clear because it acts as a secondary immune system and it is a digestive tonic that stimulates appetite and also stimulates the growth of red corpuscles in aenemia.  People there used to live to a ripe old age and knock off suddenly, which isn't the worst way to go.  But arsenic will strip sulfhydryl ions (-S-H) anywhere it finds them and these occur in cysteine, an amino acid that shows up in protein and DNA.  0.06 grams is a dangerous dose, 0.2 grams is fatal for the uninitiated, but arsenic addicts tolerate as much as 0.4 grams in one dose with no noticeable effect.

I doubt having a single LED fireball would do too much, but if you have a stock of LEDs (most of us do) that somehow get exposed to fire, beware.

[philbinator1]

So I want to build a 'lightbox'.  I saw one for sale on craigslist once.  Just an enclosure with a bunch of LED's on it, and a power jack.    I'd like to use an acrylic enclosure, a boss style 9v,  a rocker switch for power (or maybe a stomp switch), and a crapload of LED's.  The point would be to stick it under the riser on my pedal board and illuminate things.   

I guess along the lines of this: http://www.diystompboxes.com/smfforum/index.php?topic=80078.0  but much smaller.

Now my questions, after playing abound on my breadboard and frying some LED's (they smell nasty!).  A found that with LED's in parallel only the first one lit up, so they should be in series?   Does each LED need it's own resistor, or would one right out front suffice?  I know different colors need different resistance to be the same brightness, but I'm not worried about that.   To maximize brightness, what is the lowest value resistor I can use and not fry the LED's?  What color LED's would be best?  Can I just mix and match whatever odd sized LED's I find at RadioShack? 


Oh, brainstorm as I type... what if I used one power source, then wired a bunch of switches so that switch 1 would turn on a bunch of blue lights, switch 2 would turn on a bunch of red lights, switch 3 greens, etc.  Then I could mix different colors together etc.   Or use an LFO to make them switch randomly?   

this is really interesting, and a great idea!  I'm definitely going to do this, being a fan of bright coloured lights/shiny objects.    re: your resistor question, i recently tested a colour-changing led with several diff. resistor values (it wasn't changing properly with higher values, intermittent) and eventually came to 330 Ohms as the best value.  didn't fry the led, and was really bright!  I don't think its specific to that particular led coz i tried it with others and it was the same...really bright, not too hot.  but if you were to try this in a circuit as i did with my BYOC reverb (with a 330 Ohm resistor) you may find it lowers the volume w/pedal engaged...anyone else care to comment on this?  anyway other than that 2K is a good value too, bright enough but not blinding.   

i definitely want to do this project; i think i'd build 2 boxes with colour-changing leds and put them under my riser as you said.  MmmMMm lightshow.   

[walker]

This is what I found for clear enclosures.. http://www.hammondmfg.com/dwg2c.htm   I picked one up from Digi-key. 


I also considered these too, because they're bigger then the hammond D style, but shipping costs were a bit excessive.
http://www.stacksandstacks.com/organizer-catch-all-box?id=176&sku=30411&utm_medium=shoppingengine&utm_source=googlebase

http://www.spacesavers.com/acrylicbox.html?utm_source=GoogleProducts&utm_medium=productfeeds&tum_campaign=Froogle



I have a handful of LED's.  But I'll need a bunch more, and bezels.   I'll also need some rocker switches. 

[phector2004]

If you fry gallium arsenide LEDs and they smell nasty, that may be because you are inhaling arsenic or its oxide.  Arsenic is toxic (everybody knows that), cumulative (many people know that) and addictive (some people know that).  Don't make a habit of it.

mmm... don't think so.

its not good for you, but it'll take a ton of arsenic to kill someone or even make you dependent. back in the age of enlightenment and the renaissance, people would be feeding tons of it to their enemies over weeks. breathing in LED smoke will at most damage a few thousand cells, but considering the sheer number of cells that make us up, if you want to be health conscious, you're better off worrying about more important things like cardio!

as for the LEDs, you only need one resistor if they're in series, but don't burn one out or theyre all gone! (think of it as when you hook up the christmas lights and they dont seem to work!)

Even in recent history, some Yugoslavians living in the mountains near the Adriatic Sea deliberately consumed arsenic.  It works as a blood thinner that increases weight, strength and stamina, enabling people to carry heavy loads in the mountains.  It keeps the skin clear because it acts as a secondary immune system and it is a digestive tonic that stimulates appetite and also stimulates the growth of red corpuscles in aenemia.  People there used to live to a ripe old age and knock off suddenly, which isn't the worst way to go.  But arsenic will strip sulfhydryl ions (-S-H) anywhere it finds them and these occur in cysteine, an amino acid that shows up in protein and DNA.  0.06 grams is a dangerous dose, 0.2 grams is fatal for the uninitiated, but arsenic addicts tolerate as much as 0.4 grams in one dose with no noticeable effect.

I doubt having a single LED fireball would do too much, but if you have a stock of LEDs (most of us do) that somehow get exposed to fire, beware.

what have you been smoking?

aside from the DNA damage, all of that is false. there is no such thing as a "seconday immune system" nor does arsenic counter anemia (in fact, some its effects mimick it!). arsenic is not used for ANY medical purpose whatsoever.

Arsenate (AsO4 3-), the less harmful arsenic ion, is very similar to phosphate, PO4 3-. It competes with it in a step of glycolysis and forms 1-arseno-3-phosphoglycerate instead of diphosphoglycerate. This unstable ester degrades and becomes 3-phosphoglycerate. In English, you're skipping a step in glycolysis that involves some energy production so any "increase in strength" you mention is completely false.

Arsenite (AsO2 -) is the more harmful ion as it clings irreversibly to the lipoamide moiety of the pyruvate dehydrogenase complex. This stops entry of pyruvate, which we get from glucose from our food, into the Kreb's cycle. In English, you stop most of your production of energy in cells and you eventually die...

the point is, you DONT need to worry about "arsenic fumes", as RG made obvious that the plastic burns more readily than the arsenic will dissociate from its salt.

anyways, lets try and keep this on topic!

[walker]

 

[phector2004]

lol i shut up on dates...

[Taylor]

what have you been smoking?

aside from the DNA damage, all of that is false. there is no such thing as a "seconday immune system" nor does arsenic counter anemia (in fact, some its effects mimick it!). arsenic is not used for ANY medical purpose whatsoever.

To be fair, just because there is no legitimate medicinal purpose for doing something, this doesn't always impede people from doing it for medicinal purposes. There are people even today who believe that grinding up awesome seadragons and making them into tea will cure their narcolepsy or whatever. It is so commonly believed in Tanzania that albino body parts have healing powers that the president has had to publicly declare war on albino hunters. So while you're probably right about all your facts (I have no idea, but you relate them with authority) it could still be the case that people do this.

Sorry for the even further derail folks...

[walker]

alright, so any suggestions on what rocker switches to get?  Also, what LEDs to get.  Radio shack is great for a single light, but pricey if getting a whole bunch.  The high brightness ones jump out at me.  Are they worth it?  Digikey and mouser are difficult to navigate and figure out what i'm actually getting.   Smallbear is easier and has pics and bezels.  Same with pedalpartsplus.    What's this business about T-1 3/4,  T-3 1/4, etc.  what does it all mean?   

I had the idea to line the bottom of the enclosure with aluminum foil, or if I had a piece of mirror that would fit.  Maybe toss some lights in the middle, not mounted anywhere, just tossed in the box.

[.Mike]

For bezels, you should check out these at Mouser: link. I like them a lot, and am surprised that more people don't use them.

They're 5mm clear mounts. They fit in a 1/4" hole, and you push them in from the outside. The LED then clips in to the bottom. They have fresnel lenses that cause the LED to be visible from a wider angle, and protect the LED very well. I think you can get them without the fresnel lenses if you want, and there are also a few other styles available. I bet they would be really cool-- clear enclosure with clear mounts.

The LEDs snap in, but they sell two accessories to make them stay in better. One is a spacer, for use with thinner enclosures (link). The other is a clip that slides over the mount, applying a bit of pressure around the LED to make it very secure (link). You could easily skip those two parts and use a piece of clear tubing from a hardware store to maintain the full clear thing.

You can get the whole outfit for $0.42 each when you buy ten or more, or just $0.26 each if you use a piece of clear tubing for extra support.

Mike

[walker]

Update,  this is the best deal I've found on LED's, without buying thousands of them.  .20 to .30 cents (depending on color) for 5mm super brights, with resistor!   

http://www.effectsconnection.com/oscommerce/index.php?cPath=28

They also have good prices on resistors and caps, but in quantities of 10 or 25.