Our first blinky ball was monochromatic and run by an AVR driving some TLC5947s.  It worked very well but was a little expensive as each slice needed its own TLC IC.

If we had done the same setup for the RGB ball it would have been 3 times the cost in driver ICs as each 5mm LED has three light emitting junctions. 

For the LayerOne 2015 conference badge (and again in 2016) we had a PSOC4 driving WS2812 LEDs.  (Fun fact, the circuit comes from charliex's Christmas lights in 2014... when we like a circuit we really milk it.) This was great as you can make a 'serial block' on the PSOC4 that drives the LEDs and you get an ARM core all in one package.

Now if only you could mount the 5050 WS2812 LEDs on the edge of the PCB or if they made WS2812 LEDs in PTH that I could mount on the edge of the PCB.

Well it turns out they do make WS2812 LEDs in a 5mm PTH.  I got a couple of those and soldered it on to a LayerOne badge, and Yay! it worked perfectly.  First little part of the puzzle solved.

Next we need some power, the WS2812 LEDs need 5 volts the PSOC4 needs 3.3v and I want to use a 18650 Lithum Ion that runs a nominal 3.7v.  So what I would normally do is go through the TI catalog looking for a boost IC and a charger chip.  In fact that is what I did for the 2017 LayerOne badge.  It was a great power circuit, it let you charge the battery from USB and boosted the voltage to a nice steady 5V.  Unfortunately it cost about 10 bucks for just that little power section.  Charliex pointed out that what we needed was a battery bank and from there we tracked down some highly integrated power bank ICs that do boost/charge all in one chip.   So the Blinky Ball uses the same power section as the 2018 L1 Badge (same idea as the 2017 power section, with a less finicky power SoC).

And speaking of the 2018 L1 badge, the blinky ball has the same ESP-WROOM-32 for bluetooth and wifi connectivity and a mic and speaker.... for reasons.