zakqwyStarted a repo for this one: https://github.com/zakqwy/RRRYYYYYgYgGGBgB
I like the idea of a double-stacked coin cell holder. Found a decent 2xCR-something-or-other clip online, so I'll need a regulator to provide 5vdc to the microcontroller and multiplexers. I found a tiny TI buck converter chip that seems like it'll do the trick with a few as-of-yet undefined passive components (pulled a ref circuit from the datasheet). The multiplexers can't quite handle the full complement of LEDs if they're all on, but we'll cross that bridge when we come to it I suppose.
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Not sure about the HC series specifically, but it's a pretty old series, and at the time it was de-facto to drive LEDs active-low (common Anode) since most chips can drive-low quite a bit more current than driving-high...
Also, that way you could probably drive 'em straight from the battery rather'n through the buck converter (Though, I suppose, that'd mean more power-waste through larger resistors, hmm)...
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Oh, also, I've a Blinky POV somethingerother that uses one of those stacked CR-something battery-clips... One day it started to lose the blue, but Red and Green were still fine... Turns out one of the batteries was at nearly 0V while the other was still 'round 3V! Guess blue usually takes nearly 3V anyhow... If you're putting a DC-DC in anyhow, what about two CR's in parallel and a boost rather'n buck? Just an idea.
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Great call! I've never designed or built a circuit with either (a) a switching regulator (buck OR boost) OR (b) a shift register, so these comments are excellent.
I'm putzing about with ATtiny88s for #NeuroBytes v05; ironically, I could probably make the circuit simpler and cheaper and smaller using that processor to directly drive each LED out of an individual I/O channel. But it is really stupid that I have never used shift registers in a project, so here we are...
Thanks for the suggestions, @esot.eric. I'll post a revised layout at some point in the next few days taking your suggestions into account...
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Heh, to be honest, I haven't done much with Buck or Boost converters either... And I know the shift-register method for driving LEDs is common these days, but honestly I've never done it either. So take my ramblings as merely idea-points rather'n suggestions.
That's some beautiful PCBing and dead-bugging in neurobytes, btw.
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Oh hey, you're rushing for the #The Square Inch Project! I bet you could ignore all my ramblings and it'd work ;)
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