I need some recommendations for ways to discretely control 180 leds. what I want to build is a circle, circumscribed with 60 RGB leds (180 leds total) .
right now I'm thinking about eight shift registers per color group, that'll give me 64 channels, times three, for a total of 192. I seem to recall seeing a 32 bit shift register from MAXIM or maybe it was someplace else - probably cost more than 8 74hc595's would cost.
I'm thinking I'll make up a circuit board to hold the 24 shift registers, and then use headers / cable harness to wire up the leds. Or I might need to make three circuit boards, with just 8 registers each - it depends how messy the routing becomes.
I'm wondering how to calculate the update rate I can expect shifting out 192 bits of data with a 20mHz pic.
Is there an easier way I'm overlooking? I thought about some sort of multiplexing or matrix building, but the leds kinda prevent that - they'll either be common anode or common cathode depending on the cost from the supplier.