I was not satisfied with either US eyes or a Ledmatrix.
With some -rather rough- modifications I was able to position the 16x8 Led matrix as a mouth underneath the eyes.

I studied ways to have US sensor, buzzer, pushbutton and ledmatrix and I found as the best way this wiring:

A0 = Pushbutton (switches to +)
D0 = GPIO16 US Echo pin
D1 = GPIO4 SCL (I2C)
D2 = GPIO5 SCA (I2C)
D3 = GPIO0 Right Foot
D4 = GPIO2 Right Leg
D5 = GPIO14 US Trigger pin
D6 = GPIO12 Buzzer pin
D7 = GPIO13 Left Foot
D8... (More)

Time to address this issue if we want to keep our lovely Neo pixels. Who does not love our Neos. (don't raise your hand).

The problem

"The single-wire control protocol used by NeoPixels requires a very steady data stream at 800 kilobits per second. There’s a tiny margin for error, but not very much. Bits must be issued at a precisely controlled rate…the Adafruit_NeoPixel library handles all this behind the scenes, carefully counting the time of each machine code instruction. For every pixel, there’s 24 of these:"

"Meanwhile, the Arduino is normally using small fractions of time here and there... (More)