The display will operate evenings in December, from 5:30 P.M. until 9 P.M. Light outside on the sidewalk will vary from bright dusk to artificial illumination only. Viewers on the sidewalk will be lit by a post top street light and display illumination shining through the store window.

Here is a sketch of the situation.

In a normally lit room, the AIY vision camera can detect a face as much as 20 feet from the camera. This distance decreases as the level of lighting decreases. My first attempt at a "blinder" for the child zone works to about six feet from the window, but adults can be detected standing at 8 feet (possible if they are standing by the tree, but not in the street). I taped a sticky paper to the "blinder" and adjusted it to increase the adult cutoff distance. Essentially, if you can see the lens, it can see you.

I'll need to modify the blinder.