Have LED's will travel...what do I need? [Archive]

edwood saucer

08-30-2006, 05:06 PM

Well, I got the LED's today - from Hong Kong vis ebay... and before I go to the next step of creating tiny little LED clusters - I really need basic advice.

What do I need in relation to a soldering iron? I need that and flux and soldering wire - anything else?

And more importantly - what advice does anyone have when doing this? As you can tell I haven't done anything like it.

On my light's & resistors it says "Observe Precautions for handling electrostatic sensitive devices."

Unlike a computer where I touch the chasis - these are small little things - what precautions should I take?

Thanks'!

Otaku

08-30-2006, 08:06 PM

Don't worry about handling the resistors or LEDs, you can't really harm them. The precaution is probably on all their packaging. What is a "tiny little LED cluster"? Is this like a SpookyFire blob with flashing LEDs, or are you making LED spotlights? Also, what voltage will your battery or power supply be for the LEDs?

edwood saucer

08-30-2006, 10:01 PM

LED Spotlights is what I mean...

edwood saucer

08-30-2006, 10:03 PM

Haven't determined the voltage - figured I could find that out before I start building... I really want them to be battery powered as I don't want to mess with electricity.

Zombie-F

08-30-2006, 10:14 PM

Well, in order to determine what size resistor you need to use, you need to know what voltage you'll be using. For the sake of convenience, I find 9V batteries to be an excellent choice. They take up little space and one battery can drive an LED spotlight for literally days.

edwood saucer

08-30-2006, 11:11 PM

Brad Green

08-30-2006, 11:21 PM

You'll probably find this link a big help in designing your LED array. It will give you the resistor size as well as design the layout you need. http://led.linear1.org/led.wiz

edwood saucer

08-31-2006, 12:25 AM

ah yes - I have more questions than answers - but let me soak it in and see if I can't figure some of it out - thanks!

mrklaw

08-31-2006, 05:05 AM

Oh - I figured that the resistors they sent with them would work.

If I attached one resistor per light - then attached them to a 12v - could it trigger the apocalypse?
: ^)

I would like - probably a 10 led bundle.

All the LEDs that I have bought on eBay included resistors for a 12 volt power supply so no apocalypse should occur. If you are worried though, use the online LED calculators to figure out the resistance for the power supply you want to use.

If you aren't going to use up the LEDs all at once, it might be a good idea to look back at that auction and write down the LED's specs including the forward voltage and forward current.

Zombie-F

08-31-2006, 06:13 AM

All the LEDs that I have bought on eBay included resistors for a 12 volt power supply so no apocalypse should occur. If you are worried though, use the online LED calculators to figure out the resistance for the power supply you want to use.

If you aren't going to use up the LEDs all at once, it might be a good idea to look back at that auction and write down the LED's specs including the forward voltage and forward current.

For almost every LED listed on those ebay auctions, the forward voltage is usually 3.4 VDC and the forward current is 20 ma. If you can't find the specs on your LEDs, those specs should be ok to use. Build one based on those numbers, and as long as nothing goes "pop" you're a-ok. :)

edwood saucer

08-31-2006, 09:45 AM

Gre*pop*at...

I will find those specs - they have ongoing auctions - won't be too hard.

edwood saucer

08-31-2006, 09:52 AM

All sorts of stats

Reverse Voltage: 5.0 V
DC Forward Voltage: Typical: 3.2 V Max: 3.6 V
Wavelength: 390-395nm
DC Forward Current: 20mA
Viewing Angle: 20±5degree
Lead Soldering Temp: 260oC for 5 seconds
Intensely Bright

50 PCS 5mm UV LED LAMP <395nm

WINNING BIDDER WILL RECEIVE THE

SAME QUANTITY OF

RESISTORS IN 510ohm FOR 12V DC!

http://www.fizzcreative.com/haunt/voltageChart.gif

Daughter of Darkness

09-01-2006, 07:19 PM

Does anyone know how to make the LED's blink? Not the standard constant blink but in a pattern like blinking eyes? I see some on ebay but they are a little pricey especially if you need alot of them. I need LED's for dummies book. I've read a few different tutorials but none of them I read gave inrstructins on how to do this specifically.

Any ideas or steer in the right direction would be most appreciated!

mrklaw

09-01-2006, 08:02 PM

heresjohnny has a great webpage about that
http://www.hauntforum.com/showthread.php?t=1858&highlight=LED+flicker

The spookyblue method (spookyfire) is probably the easiest for a beginner.

heresjohnny

09-01-2006, 08:33 PM

Darkness you would probably need a timer circuit so the leds would be on several seconds, then shut off .5 seconds or so, then back on. I have several flicker circuits that make an led look like a flickering candle. A quick google on 'blinking eyes circuit' gives several hits, this tend to be based on a 555 chip and require soldering. You can buy blinking eyes http://www.cowlacious.com/CaveEyes.htm for xample, and you can also build mechanical blinkers like http://www.frightfx.com/projects/rats_eyes/index.htm. Hope this helps.

Otaku

09-01-2006, 09:36 PM

Terror By Design also has a Blinking Eye circuit, the EyeFX 13.

http://www.terrorbydesign.com/cgi-bin/quikstore.cgi?category=Lighting_Effects

DeathTouch

09-01-2006, 09:40 PM

Daughter of Darkness

09-08-2006, 04:36 AM

Thanks for the links you guys. I think, I may just go ahead and buy a couple of these as they are cheap enough for what I need them for. I will try and build one of the flicker circuits though. Looks like I could handle the beginner version.:devil:

edwood saucer

09-10-2006, 10:25 PM

Zombie-F

09-10-2006, 11:04 PM

Help!

Okay - I soldered my resistors to my LED's - then soldered six together - hooked to a 12 volt battery and...nothing...

Here is my home made diagram to describe what I did. I gleened the knowledge from various sites and threads - however - I guess I missed something.

If someone would take a look and let me know - I'd be very appreciative.

The resistors are in blue...
http://www.fizzcreative.com/haunt/images/diagram.gif

For starters, what value is the resistor you're using? To me, it looks as though you're using too many resistors for the circuit you're using. You REALLY should use the Parallel/Series LED Wizard (http://led.linear1.org/led.wiz) to show you how to wire everything and to know what value resistor you need for your circuit.

Dr Morbius

09-10-2006, 11:05 PM

Are your LEDS leads on the correct polarity? Remember, LEDS are diodes. They have an anode and a cathode. See diagram:
http://i23.photobucket.com/albums/b364/DrMorbius02/180px-Ledcopy.jpg
The lead near the flat side of the LED, or Cathode MUST go on the NEG terminal of your battery, or it won't light. This is called a forward bias and if any one of your LEDS are backwards, none in your series configuration will light.

Dr Morbius

09-10-2006, 11:08 PM

Hmm I looked at your diagram more closely, and it looks like you have the shorter terminals biased correctly (-). Perhaps Zombie is right about the resistors.

edwood saucer

09-10-2006, 11:19 PM

Yeah - my diagram is right - and I was really careful about which poles I soldered to which. I read that it didn't matter which end of the resistor connected to the positive pole - so I made it consistant regardless.

I will go back and look at what zombie wrote. My thought - as an amateur electrician (a real amateur) was that since I was sent 50 LEDs and 50 lights - I had to connect 1 resistor to each light. My simpletone thinking.

Anyway - if you go to the top of page two of this thread - you will see all the specs from the lights and resistors that I was sent.

So I should just have 1 resistor (but providing the correct resistance for what I want to do) at the positive pole at the beginning of the chain? Not one in between each?

edwood saucer

09-10-2006, 11:26 PM

Here is what the wizard says based on the diagram of information provided with my LEDS (if I read it correctly)
http://www.fizzcreative.com/haunt/images/voltageChart.gif
http://www.fizzcreative.com/haunt/images/wizardResults.gif

heresjohnny

09-10-2006, 11:31 PM

For starters, what value is the resistor you're using? To me, it looks as though you're using too many resistors for the circuit you're using. You REALLY should use the Parallel/Series LED Wizard (http://led.linear1.org/led.wiz) to show you how to wire everything and to know what value resistor you need for your circuit.

Zombie is right edwood. The resistors sent by BestHongKong are the right value to use with 1 LED and 12V. If you use the calculator Zombie pointed you to, and use the values of 12, 3.2, 20 and 1 you will get a circuit using 1 LED and 1 470 ohm resistor (which is very close to the 510 ohm they sent you). If you are using the 510 ohm resistor in the circuit you posted, I don't think the LEDs will get enough current to come on. If you want to use 6 LEDs, plug in 12, 3.2, 20 and 6 on the calculator and you will get a circuit that uses 2 120 ohm resistors, build that and you should be fine. Docs diagram will help you get teh polarity right on the LEDs.

edwood saucer

09-10-2006, 11:59 PM

based on what everypone has said - here is the chart:
http://www.fizzcreative.com/haunt/images/revisedChart.gif

so - I will go out and buy the 120 ohm resistors which is fine (of course - I've never bought resistors before - I'm assuming I can find them at like a radio shack?)

Then it comes down to the wiring diagram. And a question:

Looking at that diagram - it looks as if I solder the two resistors together at one end and connect them to the negative terminal and then solder the positives together and connect them to the positive terminal? Is that close?

I'm glad my mache heads are going well!

: ^)

heresjohnny

09-11-2006, 12:09 AM

Just follow the diagram: solder one end of each resistor to the negative terminal. Then solder the other end of one of the resistors to the - lead (cathode) of one of the LEDs, solder the + lead of that LED to the - lead of a second LED, solder the + lead of the 2nd LED to the - lead of the third LED, and solder the + lead of the third LED to the + power source. repeat the same sequence for the open end of the second resistor, using the remaining 3 LEDs.

edwood saucer

09-11-2006, 11:12 AM

Cool - thanks. That will be this weeks task.

Well, that and the kid is buggin me about finishing the mache heads...

: ^)

edwood saucer

09-12-2006, 04:34 PM

Quick question...

Battery size?

Am I smarter to use something like a 6volt battery for a 6 LED spot or is that overkill for what I need?

Thanks in advance!

Zombie-F

09-12-2006, 04:46 PM

Well, you can use whatever battery voltage you want. You need to figure that out first before you can figure out what value resistor you'll need to use. I've used 9v batteries just because they're small and easy to hide. I've run a set of LED eyes off of one 9v battery for 3 days non-stop before. If you remember to disconnect the battery each night, you can probably get a week or more out of one battery.

edwood saucer

09-12-2006, 05:55 PM

I'm confused... I have a large battery - for a lantern flashlight - that is a 6 volt battery. Then - you look at the small transistor batteries and they say they are nine volt.

How can such a small battery be larger in cpacity than a smaller battery?

My logic is probably wrong here - but I know ziltch about how this stuff works.

Zombie-F

09-12-2006, 06:58 PM

Size has nothing to do with voltage. The lantern battery is likely capable of providing more current for, like for a lantern. You could never run a lantern off of 4 AA batteries but off of a large lantern battery... yes you can. I think the lantern battery is overkill for what little current an LED needs to run, plus they're large and difficult to hide.

edwood saucer

09-12-2006, 07:19 PM

yeah - but I want to bundle 6 LEDS together.

My thought is this - for my vaseline marble eyes - run a pair off a 9volt.

For my spotlights (a bundle of 6) - run them of my big 6 volts (I already have a few for other stuff around the house)

I have 50 LEDS total - I need 3 sets of eyes that leaves me enough (with spares) for 6 spot lights. Again - I'm thinking out loud.

mrklaw

09-12-2006, 07:38 PM

Large batteries just last longer.
A AAA battery has the same voltage (1.5 volts) as a D battery. D batteries just last longer. A large 6 volt lantern battery is kinda like four D batteries in a single convenient box.

There is no relationship between size and voltage. You can find garage door opener batteries that are 12 volts that are smaller than a AAA battery. They just wouldn't last as long if you hooked up a constant power drain as a larger battery.

Hope that helps.

Zombie-F

09-12-2006, 08:47 PM

Edwood, you can hook up loads of pairs of LEDs to one battery with no problem, it'll just drain the battery quicker. The lantern battery would probably work best for this as it will last longer than the smaller, easier to hide batteries. If you can find a good place to hide the battery, then go for it.

edwood saucer

09-12-2006, 09:31 PM

Thanks guys - thats sort of what I was looking for - batteries 101!

So I went into Radio Shack tonight and they have gobs of every kind of resistor and had 1-5pack of 150ohm resistors. What a crock.

Anyway - I've learned a heck of a lot and thank you all for it.

Zombie-F

09-12-2006, 10:09 PM

The best places to get resistors is eBay or Jameco. On ebay, just search for the value you need, same thing goes for the Jameco site. Typically, resistors sell for about $1 per 100 in Jameco's catalog (http://www.jameco.com).

For your application, 1/4 watt resistors will suffice.

edwood saucer

09-12-2006, 10:25 PM

Ah jeez - Radio Shack had 1/4 watt - but I was following directions and went for the ohms rating!

I will order them though. We still have plenty of time. Thanks!

Zombie-F

09-12-2006, 11:07 PM

The ohms rating is the more important! The wattage is how much power the resistor can handle before it goes "pop". The ohm rating determines how much power is dissipated into the resistor which is the more important rating.

Look at it this way, the LEDs themselves can only handle so much voltage before they burn out. The resistor knocks down the battery's source voltage to a level the LED can handle without burning out, so in essence the resistor "uses up" the excess voltage and only allows the amount needed by the LEDs to pass.

TRUST ME. PLUG IN YOUR LED'S NUMBERS INTO THE LED ARRAY WIZARD (mentioned a few posts back) AND BUY THE RESISTOR VALUE IT TELLS YOU. It's foolproof. Then, just wire it up the way it tells you to and you're good to go.

edwood saucer

09-12-2006, 11:22 PM

Ha - I did that today based on all the feedback. But I didn't read past the "150Ohms"
Right below it it says
"the wizard thinks 1/4W resistors are fine for your application."

my bad.

Thanks!

dynoflyer

10-22-2006, 11:02 AM

I'm also new to LED's and wiring, but here's a thought.

I rec'd a bunch of LED's from Hong Kong, red, blue, green and UV. For power, I'll use 'wall warts' from old phones, dead mp3 players, etc., instead of 9V batteries. I use the LED wiring wizard to design the schematic (see above posts for the link).

I can wire up a dozen or more LED's per circuit as spotlights without having to unplug the batteries to turn them off each night. Now I can plug the wall wart into the timer and it's automatic shutoff feature does the work for me.

Aha! I can use an outdoor motion sensor on the circuit to turn on the wall wart for that startling effect, have one under the work bench, too! Highlight my son's zombies out in the yard when the Tot's walk past! (evil lol!)

For the spots, I'm using sections of pvc pipe, spraying the inside silver, the outside flat black and mounting onto pieces of 2x4.

If I never post another message on this forum you'll know it didn't work ;-)

UnderMan

10-16-2007, 01:12 PM

A technical word about resistors. Resistors "resist", or reduce, current flow. The LED's are sensitive to high current and voltage and will burn out quickly if directly connected to anything over 3v. In limiting the current that gets to the LED the resistor acts as a voltage drop as well. If you were to measure the voltage across the LED and then the resistor, you will find that the sum of the voltages equal the total input voltage. The trade-off is that the resistor needs to be of a proper wattage in order not to heat up and burn out. A 1/4 watt resistor is fine to drop a smaller amount of voltage and current, a 1/2 watt can disspate twice as much heat. There are also 1 watt, 2 watt, and wire wound resistors, but those would be overkill and large.
Heck, by hooking up several LED's in series you could practically eliminate the resistor(s). But if one burns out they all turn off.
Hooking them up in parallel would require a resistor on each.
Using a combination of series and parallel would cut down on the number of resistors, using one per series circuit, just hook a bunch of series circuits in parallel. Kind of a trade-off.

UnderMan

10-16-2007, 01:17 PM

A fantastic sight to take any guess work out of building LED circuits. Good job.

UnderMan

10-16-2007, 01:27 PM

#1 check the polarity of each of your LED's. If even one is backwards there will be no way for the current to flow. LED's are polarized. Most LED's have a flat portion to the plastic lens at it's base which indicates (generally) the negative terminal.

#2 you may have too many resistors. connect jumpers to them, basically shorting out the resistor(s). I'd have used one resistor in the entire group, soldering each LED to the next (observing proper polarity).

I believe it's a combination of both problems.

UnderMan

10-16-2007, 01:32 PM

1 resistor is recommended to make the circuit function properly. It makes no difference where the resistor is in the circuit, it's a matter of asthetics more so. Most people do put it at the beginning, but it makes no difference. If you are worried about too much current flowing, add another resistor in parallel to the first. This will share the current flow and reduce the heat to be dissipated in half for each resistor. This won't affect the amount of voltage they need to drop.

UnderMan

10-16-2007, 01:58 PM

Voltage of a battery has very little to do with size. The larger the battery the larger the capacity, or longer it can power a circuit. Stringing four 1.5v AAA batteries together to get 6v would run a lantern for a few hours at best, while the 6v lantern battery is good for several days, maybe even weeks. It's like filling a quart container with water and filling a five-gallon bucket. Make the same size hole in each and the quart container will empty quicker than will the bucket.

"D" cells last a lot longer than a "AAA" cell. It becomes a trade-off of portability and size compared to lasting power.

Batteries are built from "cells" of differing metals and di-electrics. This can only produce 1.5v. By stacking several cells together in series, manufacturers give you batteries of varying voltages. So a 6v lantern battery has four cells stacked, a 9v battery has six, a 12v has eight cells.

A 9v battery doesn't have as much capacity as does a 6v lantern batter, a 6v lantern battery doesn't have as much capacity as a 12v car battery. You may run a car stereo off a 9v and two "D" cells, but it would only work for a few seconds, if it will fire up at all, because the radio takes lots of current. Two 6v lantern batteries will work, but will die quickly, after a couple hours. Best bet would be a 12v battery as it can handle the current flow best and will last significantly longer.

Capacity has to do with the size of the plates, the metals used, and the di-electric used. Voltage deals with the number of plates stacked together in series. Small plates, small battery, higher voltage, lower capacity.

Hope this helps somewhat.