Controlling over 1000 rgb leds

[hicksynet]

Ok i think i have decided what way to go with, using a micros in conjunction with mosfet arrays. it will be fast, reliable and can handle high currents and as kchriste was saying if i design it right i can expand from this design.

The tricky part will be find a suitable micro, i have used atmel chips before and find them easy to use and code for. But i think i'm heading down the road of PIC processors, they seem to have everythink that is needed. Anyone have an idea of what to use ?

Also i want to try and keep each board to 16 RGB leds so thats 48 pins needed all with PWM and must be able to use a fast enough serial interface so there is no lag between boards. One more thing can i use the Arduino mega as i controller even if i'm using PIC chips on the boards ? Will they talk to each other.

 

[Pommie]

To be able to PWM 48 pins is going to require a pretty fast 64 pin chip. I would suggest something like an 18F6310. How good is your C? Writing the code to do software PWM on 48 pins at a reasonable speed is not trivial. I can help with the initial method but it is going to need debugging.

BTW, where about in Brisbane are you? I'm in Samford.

Mike.

 

[hicksynet]

Well i'm not really good at C, but i have a mate that is and he has been helping me with all the coding stuff.

Do you think to make the project easier i use 3 chips per board each controlling the different colors? that way i could use a simple chip like the PIC16F628 or if there is a Atmel equivalent.

 

[Pommie]

The 628 could manage 12 outputs at a rate of around 300Hz and a transfer rate below 150kBaud. It would have to be in asm though as it only runs at 4MHz. The 18 series chip I mentioned above runs at 32MHz and so can do a lot more.

If you do intend to use the 628s then I suggest you breadboard one with two ULN chips and 4 RGB LEDs to test it all out. Do you have a pic programmer?

Mike.

 

[hicksynet]

I have never used PIC before so its going to be all new to me, i don't have a programmer. I was hoping there might be a AVR i could use instead. But i have to try PIC sometime.

I live in Auchenflower

 

[blueroomelectronics]

More info needed
1 how big is the wall you want to light up? Feet / meters
2 what do you want to display? (static or full motion images) ie how many images per second
3 how do you plan to control it? custom PC software? *
4 how many levels of brightness? 4, 8,16, 256*

 

[Pommie]

I have a sneaky feeling it's a dance floor so probably more sensual than fast.

Mike.

 

[blueroomelectronics]

The OP said wall. But who can say. Don't need the complexity of PWM for a dancefloor. I'd think you'd want something bright like luxeons. You'll also need deep pockets.

 

[hicksynet]

I have already made the Dance floor Disco Dance Floor. I want to try the wall thing now.

 

[hicksynet]

So i think i want to go back to using 3 MC's per board to control 48 LED's any have a good suggestion on what to use? what is going to be easy to get hold of, and easy to program with. Like i said i have used Atmel before so pic is all new to me.

 

[Sceadwian]

I wouldn't use a 16F, almost any AVR is faster than a 16f. If you're going to start using pics I'd start with the 18F series otherwise you're getting a lot less chip, and unless you have some work related reason to start using a PIC there's no reason to switch from what you know. Any of the Mega series AVR chips will provide you with more than enough resources. Just go for something that has a large I/O pin count to maximize the number of LED's you can drive directly. Or use shift registers which means you can use pretty much any AVR chip you know how to program already.

 

[hicksynet]

The problem i'm having is finding a micro controller that can handle 16 channels of PWM or equivalent. I have been searching around on Farnell and cant find anything that looks like it would suit.

 

[kchriste]

You are probably going to have to do software PWM as mentioned previously. I doubt you'll find a cheap micro which does 16 channels of PWM in hardware. I could be wrong though.

 

[Sceadwian]

hicksey the current suggestion is to use a PIC at 5MIPS to do software PWM... As kchriste stated you will find no micro controller than can do 16 channels of hardware PWM. AVR's are extremely good at software PWM because of thier high MIPS per MHZ ratio.

 

[hicksynet]

Just a question, if I'm using AVR's for all the LED's and they are all linked by serial is there a limit on the number of AVR's. Also just wondering how to program them is there away to update them all via serial instead of putting every one into the programmer.

 

[Sceadwian]

The limit to the number of AVR's you can use it entirley up to how you link them in serial the protocols and hardware you end up using. You can use a single AVR or PIC to control as many LEDs as you want if the update rate is low enough, simply send data through a series of latched shift registers till they're full and then update them.

 

[hicksynet]

I was just searching around and found this site with a DMX 48 pin Control Board . Its just like i want to build, maybe a bit low on the handling current but im sure i could just add some fets to allow higher current. Does anyone no what type of chip they could be using ?