All About LED's
 

How about a thread that deals with LED's, like wiring, mounting details, resistors and where to find them. I'm thinking about lighting my truck up but have no idea where to start. I do have the tlu-01 installed and I ordered some LED's for the cab lights, but I'd like to ad some more. Any info would be greatly appreciated.

Re: All About LED's
 

So out of the 25 people that have visited this thread, noone has anything to offer as to info that I need to get some LED's on my truck?
Just something, Anything?

Re: All About LED's
 

OK you asked for it :D duh I don't know hehe I'm in the same boat just be patient grasshopper :rolleyes: some nice fellow will come along and help also google may help :p

Re: All About LED's
 

I tried google, there's too many darn links. I like reading Novels, not endless Bull****. Lol.

Re: All About LED's
 

A place I like to buy because they have great variety of sizes:

http://led-switch.com/
I can also obtain them locally at Fry's Electronics so check electrical supply places for those that don't like waiting. :D

A wizard to help you design your layout:

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

The basics are that LED's are lower voltage around 1.5-3.3V. This means they need a resistor to lower the voltage and keep them from blowing out. You cannot hook them direct to your RC battery voltage.

Wire in series is hooking a string of diodes like building a battery pack, positive to negative with 1 positive lead and 1 negative lead out of the array. It is the least amount of wires but the voltage drops across each diode (LED) so it limits how many you can hook together. Wire in parallel is separate wire leads to each diode from the source voltage which would need a resistor for every diode. This might be the simplest but it makes for a lot of wires and the resistors essentially waste your energy stepping the voltage down. The best design is one that keeps the resistors to a minimum and means arrays of diodes in series hooked up in parallel.

Plug some numbers in the wizard link earlier in this post. Source voltage of 7.2V (std 6 cell) 3.0v diode forward, 20 diode forward current, and however many lights you want. Choose wiring diagram because it is pretty well illustrated for non-tech folks. Your array will be displayed. :)

The same concepts apply whether you are hooking up chicken lights, headlights, blinkers, tail lights, etc. You CAN wire more lights to your MFU. I don't have one, but I have seen it done. Hopefully someone with experience at that will chime in.

Re: All About LED's
 

I'm no pro, but I'll tell you what i know. I've never used a tlu-01, but I build my own helicopter blades with LEDs on them to fly at night.

Leds require a specific forward voltage (Vf) to light up. It's usually 2-5 V, but there are some that run on higher voltage. If connected backwards the LEDs won't light up, but they won't be damaged. The current draw is generally around 20mA, but it can vary by color/size/make. Check the datasheet provided by the vendor. There are lots of different size/shapes of LEDs. I usually work with surface mount (SMD) which come in 4 digit size codes (ex. 0603 which is 0.063" x0.031"). Other sizes are 3mm and 5mm round like what's usually at radioshack. Visible angle is another important feature. Some LEDs have very narrow light beams like 20 degrees. That might me fine for headlights, but if you want lights along the side of your trailer something with 130 degree or more would be better.

How i build an array is first select LEDs with a Vf lower than my battery i'm going to use. I use off-the-charger pack voltage instead of the nominal voltage that's printed on the battery pack. A trick i use is to connect various LEDs in series until the sum of the Vfs is about equal or a little higher than the battery voltage. This will let me run the LEDs with no resistor. There is a little risk to this as if my wiring shorts out there will be no resistor to reduce the current. I killed one of my 160mAh lipos when my blade mounted LED/wiring came loose and shorted out the battery pack. The standard/safer method is to use a LED calculator where you type in the Vf, current and battery voltage then it'll tell you what resistor you need. There's also a version that handles multiple LEDs by the same people.

If i want to add a ton of LEDs with all kinds of colors and sizes i break the work into small pieces. Say i'm using a 3S lipo thats 11.1V nominal, 12.4V fully charged. If i wanted eight amber LEDs and the each had a Vf of 3.1 V, I'd make a string of 4 LEDs in series. Then make another string of 4 amber LEDs and connect the two strings in parallel to the battery.

Key features:
Vf Forward Voltage
Size/ mount type
viewable angle
brightness measured in mcd (milli-candela). I like 100-200 mcd

The cheapest LEDs i've found are from china :rolleyes: Ive never ordered from SatisTronics personally, but a few of the heli guys have. They are considerably cheaper than Digi Key, Superbrightleds or Allied Electronics. I'd encourage you to order a few and just play around with a soldering iron and a battery. You'll smoke a few LEDs, but they're only a few cents each ;). I use conductive copper tape and solder to connect SMDs and small wire with headsrink to connect the round LEDs.

Re: All About LED's
 

It's been awhile since I've bought or researched into LED's. I know I posted links somewhere, I'll see if I can dig them up. I had found a great domestic seller for LED's, cheap, bulk and multi packs and fast shipping, and a few good How To:'s for LED wiring.

Re: All About LED's
 

This is a very good idea. Thanks.
And thanks to everyone else for all the info. This is going to be very useful, exactly what I was looking for.

Thanks Again,
John

Re: All About LED's
 

Thanks, I'll be waiting to see if you find the links an post them.

Re: All About LED's
 

Okay, I guess the pressure's on now.....
:D

Re: All About LED's
 

Ready, Set. . . . . . . .GO!!!!

No hurry really. I was hoping to have some lights for Brookville but it's ok if I don't. I do have the TLU-01 in it now. Figured I'd better start slow and figure out what I'm doing first before I go gung ho. To be honest, it was Rod's White Stretch that did me in. That truck looks awesome. So I figured some lights on my rig would look cool, if I do it right. Now I'm trying to think of an easy way to hook up the trailer lights to what I have.

Re: All About LED's
 

Okay, here's what I've found so far. I have probably a couple hundred favorite links from older computers I'll try to look through this weekend if I have more. I think this at Instrctables was the best I found for wiring though.
http://www.instructables.com/id/LEDs-for-Beginners/
And the past few times I've bought LED's I got them here:
http://c-leds.com
This place is great, they have LED drivers, and as well know quite a bit about LED's. They've answered several questions for me via email and as well put together variety packs for me.

Another thought for some of you truckers handy with fine soldering, is SMC LED's. Those are the surface mount ones you find on circuit boards and what not, very small, about the size of a match head. Seems they might be great for running board lights, marker lights, cab lights, all sorts of things that might be lit but not room for a 3mm LED.
Not RC, but here you can get an idea of size and tips for soldering.

Re: All About LED's
 

Thanks Thor. I'll have to read more this weekend.

Re: All About LED's
 

Give me a little time and I'll see if I can draw up some actual wiring schematics for you to check out. I'll make a couple different versions. One of a truck without an MFU, one with an MFU, for those wanting to add extra lighting, and one for a trailer.

Re: All About LED's
 

Nathan, That sounds great. And I will repay you by keeping the knowledge I learn and passing it on to the next newbie that needs the info. Someday, somewhere someone will be in need.

Re: All About LED's
 

Hmmm, somewhere back in this thread it was stated that each LED requires a resistor!
Not True! I have two flatbed trailers each with 10 clearance lights (5 each side) and only 1 resistor.
I have the infrared lighting system from SS-Tronix and the whole thing is powered by a 7.2v pack mounted between the rails. Power comes up from underneath feeds to a 1/2 watt resistor then loops in and out of each led in parralel down the left side and back up the right. Works beutifully using 3mm high brightness orange LED's in chrome bezels.
If I get a chance I will show some pictures of the setup.

Re: All About LED's
 

IDontKnow, you also gotta tell us where you got the LED's, and especially where to get the chrome bezels. I can only find black bezels...

Re: All About LED's
 

Corbett, no problem at all. I'll try and get something up by the weekend.

There are a couple ways to wire LEDs. If you wire them in parallel, then each LED definitely needs it's own resistor. If you wire them in series, then you can get away with using one resistor for each set of LEDs in series.

Out of the two methods, I wire LEDs in series. The reason being that it is a more efficient circuit and the total current draw will be less then a parallel circuit. I'll go more into depth with this explaination as soon as I get some drawings whipped up!

Re: All About LED's
 

I am sorry, but you are incorrect there. If wiring in parallel you can do it with only one resistor as long as the wattage is high enough as in 1/2 to 1watt resistors.
10 LED's on my flatbeds both wired in parallel with 1 resistor and been working perfectly for the last 6 months! No overheating of anything all LED's are bright and uniform in light output. Current draw? Minimal Charge the 7.2 volt 4000mAH battery about once every two to three months. The resistor size is 330ohm 1/2 watt
Will post details on the Bezels and LED's when I find it again

Re: All About LED's
 

As requested, this is the place where I got the Chrome bezels from and also the LED's.
http://stores.ebay.com/Asia-Engineer

As to the Bezels I used on my flatbeds, these ones:
http://cgi.ebay.com/50-pcs-5mm-Chrom...item563f6e5421