I am trying to create a project much like like a Marquee sign, I want to be able to control hundreds of LEDs from a set of chips.
From my research I found the 74HC595 chip and using a bunch of these would probably work, but it would be nice if I had the ability to change each intensity of each LED like each LED pin had its own PWM controller on each LED ?
Is there a chip-set out there that would do some thing like that ?
Thanks Sid.
"hundreds" means an array of 10x10 to 30x30 or so. This is not outside the realm of possibilities for a small MCU with enough pins. Even using a second MCU just to run the leds wouldn't be *too* tricky. Next up would be using an FPGA to run the matrix, since you have far more pins and hardware PWM options. At the top of the list would be an LED display controller perhaps? Or an OLED display driver?
TI has a range of LED display drivers, like the LP5890, if you can solder them. And obtain them ;-)
Or you could build your display out of smart RGB leds, like the kind they use on programmable led strips, and let them manage their own brightness.
DJ, The 'LP5890' chip has some nice features, it would work. Thank you for that. What did you mean in your last statement ? "... let them manage their own brightness." How would they do that ? Is the PWM feature built into the LED ? Sounds expensive.
Thanks
Yes. The LED itself has a tiny MCU in it with a serial port. For example:
Very :-)
Mike Harrison has a video from some years ago that explains a neat hack for doing that sort of job.
Cheers
Phil Hobbs
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