Build Your Own Clone Message Board

I'm making a few light plates for my existing pedals, but I have no idea how to add another LED to it. In effect, having 2 LED's -- one on the top, one inside the enclosure shining thru the light plate on the bottom.

Any help would be appreciated.

Easy, you can wire them either in.parallel or.in.series. you may wish to adjust the CLR to get the brightness where you want it. Try googling "LED series calculator". There are web pages that design the network for.you and tell you what resistor(s) to use, etc.

"CLR"? Sorry for the n00bness!

Current Limiting Resistor.

Make no apologies for n00bness, bro. Make apologies for not asking questions and learning.

so i guess the question at hand is:

how many leds can you add to a project before you start to sap power away from other more non aesthetic portions of the circuit?

at that point could you add a larger power supply and a voltage divider (or regulator??) or something to drive the leds and the circuit independently?

Ive been kinda toying with this idea a bit, got my first arduino recently and had the idea of adding stuff like LCDs and junk to a uber pedal and have been stymied about the power issues.

Really, I only need to add one or two at the most. Not sure what I need to do, I' m really better with a visual aid [hint-hint].

here are some basics.
LED's in series:

In series wiring the forward voltage drops are additive, but the current requirement stays the same..........for example, if each red led has a 2 volt forward voltage drop and a maximum 20 milliamps, and you put 2 in series, then you will need 4 volts at 20 milliamps to drive the leds to maximum brightness........If you had 6 red leds in series, then 12 volts at 20 milliamps is required

LEDS in Parallel:

In parallel wiring, the current requirements are additive, but the voltage drop remains the same; for example, if each red led has a 2 volt forward voltage drop and a maximum 20 milliamps, and you put 2 in parallel, then you will need 2 volts at 40 milliamps to drive the leds to maximum brightness........If you had 6 red leds in parallel, then 2 volts at 120 milliamps is required

i do know that one of the methods drains your power supply more rapidly ( hence my question about how many before things start getting iffy)
but i will defer to more intelligent heads on the subject.

I'd need to lower the resistance to the LED's depending on the number of them. Ok, I think I get it now. Thanks very much, guys.

Ok, so I've been working with the above for a few days now. Specifically, I added an 8mm high brightness orange LED to the underside of my old-version BYOC tremolo, poking through a plexi sheet cut to size. The existing CLR is 10k, I lowered it to 4.7k, making both LED's a tad brighter. I then lowered it to 1k, and there's an interesting thing happening. Both LED's are fairly bright now (although I may try to go even lower and see what happens), but the LED will go to solid -- meaning non-blinking -- if the rate is turned all the way down or up. Switching the effect off and back on again will reset it, but will re-occur when you min or max the rate.

Something to do with the CLR or something else entirely? I don't want to brick my pedal by messing with something I don't really understand!

I don't know if you want to go any lower than 1k - you don't want to burn up the LED.

I see. But isn't having 2 LED's wired in series essentially "sharing" the load?

I've made builts with up to 5 leds in them, 2 separated and 3 in serie.

For the grouped 3 i did'nt really noticed a big difference, from a single one with 1k CLR or the 3 together with a 1K CLR....

You need to raise the value of the CLR alot to notice a major difference.

Yes, they are.. But there's still a limit on how low you can go with the resistor. I have no idea what that limit is, though, so please take what I say with a grain of salt.

using this calculator might help:
http://led.linear1.org/led.wiz

it typically produces a design with the lowest possible value for the CLR. For example, for two LEDs in series, with forward voltages of 2V and forward currents of 30mA, you can use a single 180 ohm resistor. The calculator suggests a 1/2W resistor, but realistically you'd be just fine with a "standard" 1/4W size - it only needs to dissipate 162mW.

Something to be aware of is that if there is a significant difference in the forward voltage of the two LEDs used (i.e., a standard 1.7V red diffused LED on top and a superbright 2.2V on the bottom), then you can still wire them in parallel, but each branch should have its own CLR. This will prevent the bigger LED from using up most of the current and dimming the smaller one.

Here's some more useful reading on the subject:
http://www.kpsec.freeuk.com/components/led.htm

The calculator above suggests a series array, but you could figure out the numbers pretty easily for a series array if you're handy with basic algebra. Just remember that voltage is the same in parallel, so each branch of the LED circuit will use 9V. I can try to draw you a schematic if it would help.

Yes, please, and THANKS! You said "basic algebra" and I nearly did a spit-take on my monitor. Haven't used algebra since college and can't recall any of it!

Ok, we have a new wrinkle to this discussion:

Messing with the CLR for my BYOC trem (old version) has rendered it broken. Signal passes through, LED lights, but there is no trem at all.

Any ideas?