geekhack

geekhack Projects => Making Stuff Together! => Topic started by: HeroXLazer on Wed, 01 March 2017, 20:32:15

Title: RGB LED PCB Help
Post by: HeroXLazer on Wed, 01 March 2017, 20:32:15

So, I want to use a LED driver with RGB LEDs, and I want to use SMD RGB LEDs that only have four pins. They have a R pin, a G pin, a B pin, and a VDD/VCC pin. The driver I'm going to use uses Charlieplexing, and I'm confused on how to Charlieplex with single pins. I figured out to do it if you have two pins on each LED, but not with one pin. Could someone please explain how to wire it to the driver?
MCU: http://www.atmel.com/Images/Atmel-7766-...ummary.pdf LED Driver: http://www.issi.com/WW/pdf/31FL3731C.pdf RGB in LED Driver Example: http://www.issi.com/WW/pdf/31FL3732.pdf RGB LEDs: http://www.lumex.com/sml-lx0404siupgusb

Title: Re: RGB LED PCB Help
Post by: poang on Wed, 08 March 2017, 22:24:59

why don't you use ws2812b？

Title: Re: RGB LED PCB Help
Post by: pomk on Thu, 09 March 2017, 01:20:10

Quote from: poang on Wed, 08 March 2017, 22:24:59

why don't you use ws2812b？

My guess would be cost and more importantly the lack of reverse mount option or some other size constraint.

Title: Re: RGB LED PCB Help
Post by: HeroXLazer on Thu, 09 March 2017, 08:23:59

Quote from: poang on Wed, 08 March 2017, 22:24:59

why don't you use ws2812b？

I was going to, but then I thought about assembly.

Title: Re: RGB LED PCB Help
Post by: cribbit on Thu, 09 March 2017, 12:19:28

Charlieplexing is really, really hard to describe.

A ws2812b is just as hard to stick on as a normal SMD LED.

You're going to have an easier time just using a standard matrix.

Title: Re: RGB LED PCB Help
Post by: HeroXLazer on Thu, 09 March 2017, 16:36:21

Yeah, because of that I just decided to use the ISFL3733, it's not charlieplexed. The hardest part is going to be firmware.