LED info needed. Custom Cluster Idea

Hey fellas, I'm looking to do a custom project with my spare gauge cluster. Here is a pic of what it it looks like underneath (this is another persons cluster… it is just to give you an idea of what it looks like underneath… obviously mine doesn’t have the glow wire.) What's under the gauges Anyhow, here is what I had in mind! please excuse my crappy GIF, but it helps give the idea :) Now, obviously my stock lighting was not meant for this type of work, but that is allright because the factory lighting is quite dim in stock form Anyhow. So what I wanted to do is get some circuit boards (that I can customize) that I can place some White LED’s on so that I can light up the cluster a bit better. As for the tach changing color, well I figured I could use some sort of shift light RPM switch. I just gotta figure out how I would go about making the white LED’s go off on the tach & then turn red at a certain RPM. Now I’m pretty new at this stuff, but I’m willing to give it a shot as this is a spare cluster of mine. So I have a few questions! *Where can I get some good pieces of circuit board that I can cut to fit my cluster? *Is there a particular type of LED that might work best for what I’m trying to do? *Would you guys recommend getting a Lot (100qty) LED’s from ebay? *Is there a certain way that LED’s need to be hooked up for them to work properly & last long? *Any ideas on how I could use the rpm switch to get the tach to light red? I mean I have some ideas… but it cant hurt to get some more input. *Also, when looking at LED’s I noticed that the LED’s had an MCD rating… which I’m not sure what that means… is that just to tell you how bright they light up? Examples: 27,000MCD 50,000MCD

out of topic but is that a mr2  turbo guage cluster by any chance?

No, it is an N/A MR2 cluster :). It's from my old MR2 that I parted out last year.

Any input, anybody?

mcd = millicandela = measure of luminous intensity = light output As for the other question I am a fan of relays, although there may be a simpler method to my madness at times.... I'd see if a small SPDT relay would be able to do the trick, use the RPM switch to trip it.

or you could find some way to reverse polarity, that way when you get to your rpm the polarity switches and white goes out red goes on, just an idea

Well, as far as the LED's on ebay, i have purchased a couple hunderd LED's from besthongkong or something. both orders were priced great and they work great. so it's worth a shot for the number you get. they were 12,000 mcd and work great in cars and dashes. That said, the biggest problem you'll have with LED's will be keeping the illumination on the gauge face even. the EL wire shown in the link would be a better option. They sell 12V sections of EL wire for computers and cars. That may be a better option for your base illumination. As far as getting the red, you could either pick up some red EL wire or try some LED's. You'll have to experiment to see if the red will overpower the white and look good. Also, if there is a turn-on delay associated with the EL wire then you'd have to overpower it with a cluster of red LED's. You can buy some perforated circuit board at any electronics shop and build your led circuit on that. you could even have the complete ring on a board with side-by-side LED's so you'd have great illumination. As far as you question about how to properly wire LED's you should just do some research. Teach a man to fish, give a man a fish kinds thing. A LED has the same characteristics as a regular diode (hence the acryonym light-emitting diode) so expect a voltage drop across it. Now, always remember that the intensity and life on an LED is directly proportional to the current you run through it. The voltage drop of the LED is only part of the circuit. you put a resistor in series with the LED in order to set up the amount of current through them. Without a resistor, the current will vary with voltage. follow Ohm's law and you will be able to calculate the necessary resistor value for a corresponding voltage drop. if you do not know ohm's law then please learn it before you just toss parts together. a correctly designed circuit will always work on the first try. For instance, the LED's i bought on ebay want 20mA to acheive 12,000 mcd for roughly 80,000 hours. And i measured a 3.3V drop across them. So if i put three in series i have 9.9V total drop. I design for 13.5V (even though 14V is possible, the LED's can handle 25mA without much difficulty) so i have basically 3.6V left. Divide 3.6V with 20mA and you get 180 ohms. so a 180 ohm resistor will provide 22.8mA into the LED at 14V but only 11.6mA at 12V. For your application this won't matter since your car will be running and have the highest alternator output at full rev anyway. Just use a volt-meter (or standard DMM) and calc the actual voltage drop of your LED's using a 470 ohm resistor in series with a single LED. And after you build your circuit, check voltage drops and current with your DMM to ensure the product matches the design. Like kardain said, you can always use a relay, but using a transistor as a switch is trick and uses very little current. of course, that would require a basic knowledge of circuit design or just a weekend with a book. but a relay with normally open and normally closed contacts would do it like a champ with a very slight delay. As far as triggering the needle, this may be accomplished mechanically with little effort. However, you may want to consider using a transistor or logic circuit circuit instead of a relay in order to keep the wires small. What i am brainstorming is this: when the needle makes it to your redline point, it physically makes a connection with a spring, thus providing an input to your logic circuit (a closed-contact or high-level input.) a spring isn't necessary thought, just have two wires or conductors attached to wires contact when the needle is at and past that redline point. i'd make sure to not provide too must resistance so you don't damage your needle though. just an idea. if you have something that already lights up, but is currently just a jewel light, then have the voltage at the jewel light power your relay to turn on, thus the normally open contact closes and you red LED's come on till the jewel light turns off and the relay turns off again. the normally closed contact could have turn off the white LED's (if that's your method). let me know if this was of any help peace Electrons behave like waves on monday, wednesday, and friday, like particles on tuesday, thursday, and saturday, and like nothing at all on sunday.