Multi-colour LEDs: anybody tried these?

[Mark Hammer]

I saw some "RGB" LEDs on the Tayda site yesterday and ordered a couple just to see what they're like: http://www.taydaelectronics.com/leds/round-leds/rgb-led-5mm.html

Do these things produce other colours when two of the LED colours are selected, or do you just see a red and green, or green and blue pinpoint when using two of the enclosed LEDs?

Makes for an interesting alternative should one have a pedal with multiple modes selected by rotary switch, toggle, or e-switching.

[Earthscum]

I actually got 2 in about a week ago. Played around with just mixing the colors, but was contemplating trying each color off the first 3 stages of an AN6884, and use a pair of other LED's and see what it does. Actually, I'm procrastinating, because I'm staring at all the parts, just don't want to pull apart the breadboard at the moment. 

[Keppy]

They can be blended, though you always see the separate colors if you look close. The biggest issue is that one color (red in my experience) tends to overpower the others if you use the same current. You have to tweak if you want a good blend.

[Earthscum]

That's what I was getting. About a 2.2k on the Red cathode blended nice with 1k on the green and blue @9V.

[haveyouseenhim]

From what i understand you need a micro controller with pwm outs to have these work like they should. i like the 7 color led from radioshack it has a controller built in.

here's something i did with the 7 color leds:

http://www.youtube.com/watch?v=gp6eGD6iF5o

[PRR]

> green and blue pinpoint

I got some large frosted tri-colors and they do glow all over, not pinpoint.

As Keppy says, same voltage/current makes different eye-impact in each color, you may need 2:1 differences in current to get an in-between color. For some small set of colors, breadboard finds the right resistors. For a wide palette, the microcontroller may be less fiddly.

Even in clear package, I imagine that at foot's length the pinpoints would merge, just like the color dots on a TV or computer monitor.

[Earthscum]

You see a little rosette of the 3 colors around the outside of the center on these. Not hard to "frost" clear LED's, though. 00 or so steel wool works nice, gets all the way around.

Anyone reading this gets a neat trick. Pop your LED through the hole in your enclosure, mark it, and make sure you aren't going to cut through to the die. Then you can grind/sand/cut it off and "frost" it for a super clean flush look. 

[Mark Hammer]

Neat!  It's sort of what I was expecting, but glad to have my expectations confirmed.  Thanks.

[R.G.]

I've thought about experimenting with an LED that will announce the on/off state by blinking out the letters in Morse code. It could also do "SOS" to indicate low battery.

[CodeMonk]

I have done the grinding bit on LEDs for the Light Emitting Border thing, but never really thought much about a flat LED for the status.


Anyone ever tried it with square LEDs?









I have a few rectangular ones like these I ordered a few years ago by mistake

[Mark Hammer]

I've thought about experimenting with an LED that will announce the on/off state by blinking out the letters in Morse code. It could also do "SOS" to indicate low battery.

My ambitions are more modest.  I was thinking about something that could tell me from a distance which of a half dozen fuzzes in a rack panel were active at the moment, without having to mount and wire up all those individual LEDs.

For folks intent on using a PIC or Arduino as a modulation source, such an LED could serve as both a rate and waveform indicator.  I.E., when it's a sine wave, it blinks purple, and when it's a ramp wave it blinks green, etc.  I know Mike Irwin showed me a rate indicator he had made for a phaser some years back, where there were two LEDs to indicate rate, one for the positive peak and another for the negative.  It blinked twice for each cycle.  That was particularly helpful for slower modulation rates, where it could be a long time between successive positive peaks.

Or, you could just buy a few hundred thousand and make your own end-zone video highlights screen.