Four 5mm NeoPixels are now installed on the prototyping board. Individually, they work well with the TrinketPro as a controller. Software development is in progress to produce the most usable display. To be most useful, the code needs to make it easy to independently adjust the hold times for full inspiration and full expiration, as well as the times for letting the breath in and out.
The next hardware task is to test the power supply. I've chosen the Adafruit Pro Trinket LiIon/LiPoly Backpack Add-On and a 105mAh Li-Ion battery. A 500mAh battery is also available if more capacity is needed. The NeoPixels can draw quite a bit of current, but maximum brightness is not needed for the application. In fact, it would most likely distract from the purpose, so we'll be running the LEDs at lower current levels.