sidmonster

LED matrix games and animations

2 posts in this topic

Hey guys, I've been looking at some of the pre-made 8x8 LED matrix available, and I think I'd like to use one of these for a clean, simple installation.

A few questions:

1. is it necessary to use transistors? Or can I simply hook them up as shown in the default DOUT wiring schematic? (MBSID) What is the advantage of using transistors?

2. I have seen computer software for some simple LED matrix projects that allows you to program animations and simple graphics to display on an 8x8 matrix, would it be possible to play these on the midibox somehow? I know it's possible, but would it be realistic for someone who has no assembly language experience?

3. As a workaround, I have considered getting a bi-color matrix and hooking the second color up to a dedicated control board that would allow me to play little animations and graphics when I'm not using it for midibox, since both colors share a pin (either cathode or anode) would this cause any damage to my DOUT?

4. Check out some links that got me inspired:

http://www.youtube.com/watch?v=JqH4_tATKhc

I look forward to hearing your thoughts on this!

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Transistors in this application are used for "current sinking". Normal LEDs connected to a 74HC595 won't really need transistors, but ultra bright or grouped LEDs may draw more current than a 74HC595 can handle. In that case you need transistors, which act sort of like solid-state relays for this purpose.

As for games and animation: dude, I just started trying to make a few simple modifications to MB-808 (PIC assembly) in the past few days. I've got a sharp aptitude for programming, but I'm finding myself constantly stumped with the simplest of tasks.

Nothing is too much to take on, but it's all about how far "down the rabbit hole" you want to go! In PIC assembly, you won't accomplish much in an evening if you don't already know anything about it.

The STM core, however, is fast enough to do almost anything you could want in C, so you don't need to use assembly language. It's arguably easier to work in C.

Regarding your third question: if your DOUTs can handle your LEDs for MIDIbox, then they can handle your LEDs for anything. If you're in dout (pun intended), try your circuit on a solderless breadboard first! 74HC595 ICs cost approximately a dollar each (probably much less). If you fry a DOUT, you are out $1 and you need transistors.

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