Ok great,
I will look into your suggested POE injectors, etc...
So here is my rough draft of RPi parts to buy...
@jthornton @Mouthpear
https://www.adafruit.com/product/3782 encoder for position. If I understand correctly, from door open to close it should be able to count the "windows" or interrupts for motor to turn on OR off. I just don't understand how it would know where "zero" or start is... in automotive, crankshaft sensors have teeth (same as the "widows") but one is missing, and when the sensor see the missing tooth, it knows it as "zero"
https://www.adafruit.com/product/3985 for encoder wheel for position
https://www.adafruit.com/product/3766 motor wheel for movement
https://www.adafruit.com/product/3802 motor, but looks like a tight fit to get the encoder and interrupter and motor wheel all on the 1 shaft... I picked this motor because of the all metal gearing, gear ratio, resulting in higher torque but slower rotational speed .
OR
https://www.adafruit.com/product/3777 gives more room to mount parts due to two "shafts"
Next part would be which RPi, the Pi zero ($14.00) is great, but not POE without adding an ethernet HAT/Splitter($8.00),($10.00) one micro USB, speaker Bonnet with speakers ($15.00)...etc I like it because of the size BUT it ends up being more expensive than a Pi 3 B+
($35)... which has POE via splitter($10.00), 4 × USB 2.0 ports . Having that many USB ports I can run 2 USB cameras,( as well as the Pi ribbon camera) and USB speakers.
A Pi 3 case with a fan is $10.00...
Again open to suggestions/opinions...