Since my build is slow, I figured I'd share something cool that I figured out with light pipes.  I'm using a deep frame, and I wanted the ambient light sensor to be as unobtrusive as possible.  I wound up using this product ( https://www.amazon.com/gp/product/B01M7ZFV01/), which has a couple of cool features.  It's a light pipe, and it has a molded Fresnel lens at the top, so it transmits off axis really well.  Even a light from the side is directed down the pipe.  The other thing that's neat is that the lens at the top acts as a slight flange, so it can be inserted into a hole but won't go all the way through.  It's less than $3 for a pack of 10.

I drilled a hole in the top of the frame, and the light pipe is not very visible at all.  Here's what it looks like if you can see the top of the frame:

But more likely, you'll be looking at the frame edge on, and you can see that it barely sticks up above the frame.

I used the 1" length light pipe, which just barely sticks out through my thick frame.  The trick was to mount the light sensor to a board so that the light sensor is up against the light pipe.  I did this by mounting the light pipe about halfway deep in the frame, and then using a pair of angle brackets to hold a piece of hardboard with the light sensor at exactly the right spot.  In this photo, you can see the light from above being sent down the light pipe.  The input to the light sensor is well enough controlled that it only detects light from the top of the frame.  The board shields it from any light from the LEDs on the map, and the deep frame casts enough of a shadow that the only light that reaches the sensor is through the pipe.

This particular light sensor ($7 for 3 off Amazon, I think) has a small screw hole, so a #4 screw holds the sensor to the hardboard.  The sensor has two lights.  The right light is for power, and will always be lit as long as you supply voltage.  The left one is the digital out reading.  If the sensor detects light, the left LED will be lit.  If it doesn't, the LED will be dark.

As you can see, I built a JST connector.  On the Raspberry Pi end, there's a 3 position connector that supplies 3.3V (yellow), ground (black), and the digital out signal (green).  I crimped a 4-position connector on this end, and as long as I remember that I'm not using analog out, I know which pin should be left unconnected.  This lets me disconnect the light sensor easily should I ever need to do so, and of course the other end is also crimped so it's easy to pull off from the Raspberry Pi/breadboard when I need to do troubleshooting.