LED Lighting.

[TireSpin]

Hi There Experts,

I would like to light up my life and my track with some LED lights. I need to be honest and state that I know absolutely nothing about electronics, amps, volts and so on. I don't know if there is any hope for me? If anyone could provide some links to sites or ideas of where I should start I would be very grateful. I know that forum member JJJ is very good with this type of thing so perhaps he can shed some light on the subject, pardon the pun.

Anyway, thanks in advance for any help.

Regards,

[JJJ]

Hey TireSpin,.

Yes I have helped other members with lighting their tracks, some of whom had no electrical know-how. Most seem to have been able to understand my teachings, so I'd be happy to pass on my knowledge and hopefully take your track to the next level. PM me with your requirements or at least a basic overview of your plan, and what you hope to achieve. Let me know your skill level with a soldering iron also, if any.

[dangermouse]

Hi Sensai JJJ

Does your teaching in the mystical arts of electronics include lights for cars?

cheers
DM

[1/32 slotter]

Hello
I think this is a very good topic idea. Now all we need is someone to post a basic how to.

[JJJ]

Hi Sensai JJJ

Does your teaching in the mystical arts of electronics include lights for cars?

cheers
DM

Ah Grasshoppa, hai, lights for cars, we can do that.

[JJJ]

Hello
I think this is a very good topic idea. Now all we need is someone to post a basic how to.

Be happy to post a basic how to. But not tonight, its Friday and I'm already thru a bottle of wine with the wife (wee bit tipsy) and friends are coming in about an hour (might even do some racing), so unless some sober expert can beat me to the punch, please give me 'til tomorrow, and I'll come up with something for ya.

[1/32 slotter]

Your making me jealous. Time to brake out the crackers & cheese

Joel

[RichD]

Here is the LED lecture. LEDs operate at low DC voltages and the use very little current (amps). The LEDs that I use take 20 or 30 milliamps each (0.02 to 0.03 amp). At 20 milliamps a 1 amp transformer can run 50 LEDs and at 30 milliamps the same transformer can run 33 LEDs. Red LEDs run at the lowest voltages, about 2 volts, the higher powered white or green LEDs run at about 3.5 volts. You can either use a variable power supply and set it for the voltage that you need or use a higher voltage power supply and put a resistor in series with each LED to drop the voltage to the required value. I like to wire all of the LEDs in parallel. Besides being available in different colors LEDs have different light intensities and viewing angles. Smaller angles like 15 degrees are like spotlights, bigger angles like 45 degrees are like floodlights. The brightness of LEDs is usually specified in mcd (millicandelera). The LEDs used for headlights in slot cars might be several hundred mcd, if you wanted to light an oval track for night racing LEDs rated at several thousand mcds would be used.
In order to use LEDs you have to look up their specifications. There is a typical operating voltage, a maximum voltage, a typical operating amperage, light frequency and viewing angle. In order to select the right dropping resistor you need to know the diode forward voltage and current plus the source voltage. There are websites that can do the calculation (here is one: http://led.linear1.org/1led.wiz) for you but it is fairly simple to do it yourself. I am building some lights for an oval track and using white LEDs with a 8000mcd output and a 45 degree viewing angle. The LEDs operate at 3.5 volts and use 30 milliamps. I am using a 13.8 volt regulated power supply. First off I need to know how many volts I need to drop across each resistor, that would be 13.8-3.5 = 10.3 volts. The voltage drop across the resistor will be proportional to the current that the LED uses so dividing the voltage drop by the current in amps will give you the resistance needed. In this case 10.3/0.03 = 343 ohms. The nearest available resistor would be 390 ohms and it would be best to use a 1 watt resistor. Since LEDs are diodes they only conduct in one direction, the longer of the two leads is connected to positive.

[JJJ]

Addendum on LED Lighting

Hey TireSpin, seems like your post has generated some interest, good thread idea. Thanks Rich for your input. I thought I would add some more info and hopefully make it seem a little less daunting.
First an answer to a general question, "Why LED lighting vs incandescent?". Several reasons: 1) Best reason is that LEDs (Light Emitting Diodes) last far longer than incandescents, virtually forever. 2) They require less power to operate and put out virtually no heat.

LEDs come as either 5mm or 3mm. I tend to use mostly 3mm as they are smaller and will fit into more spaces. Here's a picture showing the difference:

LEDs are powered by DC voltage, which means that a positive (+) wire and a negative (-) wire will have to be identified and the wires of your power supply must be identified as + or - as well. See from the pic above that you can identify the + lead of the LED by its longer leg, and the - lead by an indent in the plastic near the bottom. OK, decisions about power supply should be based on what you can find around your house. Most people have DC power packs laying around from old cell phones and electronic gadgets. Look around and see what you can find. It must be a 120VAC (house receptacle power) to xVDC transformer something like this one:


From the first picture, I stripped of whatever connector was attached and exposed the bare wires. By now you will have bought/ordered the correct resistors for the transformer you found (or bought), you can use an LED online calculator for this as Rich mentioned. Input the source voltage, the LED current (20mA), LED voltage (3.3V) and 1 LED. The program will give you resistor value. Now you must determine which lead on your transformer is +. If you don't have a voltmeter, you will have to make a little jig from an LED soldered to a resistor. For 5VDC, a resistor around 100 to 220 ohms should work. For 12VDC, use 470 ohms. When the LED lights you will know the correct polarity by the markings on the LED above. Wrap a piece of tape to mark the + wire. Note the specs listed: Input AC 120V, Output DC 5.0V, 800mA. Each LED is 20mA, so 800mA will power 40 lights.

LEDs can be bought as warm light or cool light, just like fluorescent bulbs. The warm light is like incandescent tending to off white brown shades, the cool white is harsh white light like a fluorescent, so buy the one that mimicks what you are trying to duplicate in miniature. Buy the LEDs tht say "bright", for streetlights, at least 5000mcd like Rich says. I use these for cars too.

OK, we already talked about soldering, and this is an important tool. Buy a good one like the one below with a holder and a sponge. The sponge should be moistened with water to clean the carbon off the tip once in a while. These irons are about $15 from your local store. Also buy the resin core solder and a tin of flux:

Every wire you join should be stripped to bare wire (about 1/8") and apply a little flux to it. Touch the tip of the hot iron to the solder just enough to get some on the tip, then apply the tip to the 2 wires just for an instant, you'll know when its worked. Practice a bit with some spare wire.

Well that's about it. Wire your track LEDs in Parallel like Rich says, which means for example: run 2 lines of copper tape (+ & -) around the bottom of the track table. Solder your transformer leads to one end and then wire each LED light with a resistor (resistor can be soldered to + or - lead) to the copper tape at its location.

Next: car lights. These I wire in series. Stay tuned.

[1/32 slotter]

Triple J it sounds pretty good to me. I'm sure that I will have 1000 more questions when I start. And I don't see any pics.
RichD thank you for the calculator. I didn't know who had one on the net.

Joel

[JJJ]

Hey Joel, thanks for the heads up about the pics. I can still see them, can anyone else not see them too?

[Rush2112]

I don't see any either on Firefox.

[JJJ]

Here they all are again as attachments. Now you got me wondering about other posts, hmmm.

[scrjon]

thats great JJJ now I can use those other LEDs you sent me thanks I see all the photo

[TireSpin]

Wow, Rich D & JJJ thanks for all your input. You make it all sound so simple. I think I read both of your replies about 3 or 4 times and I think I have half an idea of what you are trying to teach.

To give you a little back ground on what I would like to attempt is I would like to light my track like Nascar does. That is to say that I would like to have both track lighting like JJJ does with the Bic handle lights he has around his track and I would also like try something I have not yet seen by anybody.

I would like to light the track by using the inner track wall with small mirror box's that would reflect the light across the base of the track much like the real thing in Nascar. As I stated before I have no electronic experience.

I have managed to use a soldering iron without being rushed to emergency or having the Fire department stop by (so far).

It looks like I can get started on my first homework assignment by finding what I have available to me for power supplies?

Can you PM me with any links you may have to where you would purchase your LED's and resistors?

I am glad to see that other people where interested in this subject as well. Maybe we can all learn from the experts on these forums?

I am very grateful for all of your replies.

Thanks Much