SparkFun Forums 

Where electronics enthusiasts find answers.

Have questions about a SparkFun product or board? This is the place to be.
By sledhead
#179988
I'm a novice so forgive me if this sounds crazy. I want to use the red/green 8x8 led matrix as a baclight for an annunciator panel. I need to have all the LEDs come on steady, 1 of 3 colors depending on what terminal I power up with 12v DC. Any assistance on how to do this would be greatly appreciated.
By lyndon
#179991
Assuming you are changing all the colors at once, it doesn't look like there's anything to it besides wiring it up and possibly selecting an appropriate dropping resistor. How are you planning to select colors?

It might be much easier to use a single RGB LED and a diffuser panel if the area you want to illuminate isn't too big.
By sledhead
#179999
It would be set behind a 2x2" translucent panel with black lettering on it, the mechanism for setting the color would be 12 volt dc signals from a plc, 12volts to green when all is well, 12volts to both green and red (yellow) when getting into the danger zone, and 12volts to red when in alarm. Currently the desired effect is created using 6 12 volt incandescents (2 for each color) it is just getting to be a nuisance replacing bulbs all the time.
By Mee_n_Mac
#180000
What level of current can each 12v source supply ? If you want all 64 LEDs on at the same time, it'll take ~1.3 A. You'll also need some way to "convert" 12v down to the LED voltage. That can be as simple as some resistors or a more efficient DC/DC LED driver. A driver is more $$s and you'll need more than 1, but they can reduce the current needed from each 12v source.

Though in either case I'd have to pause and think about how to do it for your case (all on simultaneously). These displays were intended to be multiplexed, one row/column on at a time, but updated fast enough that a human doesn't see them being off 7/8'ths of the time.

PS : what (link) matrix is it ?
By lyndon
#180004
Simplest solution is probably a few inches of RGB LED "tape" It's rated for 12V out the box and has separate contacts for R, G,, B & ground. Worth a try.