HowTo use Raspberry Pi & OpenCV to track objects & turn servo

How I made my Halloween skeleton head turn to watch people as they walk by using a Raspberry Pi Zero, servo, camera, and OpenCV python library.

Parts:
Pi Zero W (with wireless): https://www.adafruit.com/product/3708
PWM Servo bonnet: https://www.adafruit.com/product/3416
Servo: https://www.adafruit.com/product/2307
USB to Barrel Jack cable: https://www.adafruit.com/product/2697
Pi NoIR Camera (camera without an IR filter that's better at night): https://www.adafruit.com/product/3100
camera cable that fits Pi Zero: https://www.adafruit.com/product/3157
USB Hub: https://www.adafruit.com/product/2991
mini HDMI to regular HDMI adapter: https://www.adafruit.com/product/2819
BYOS (bring your own skeleton)

Guides I followed:
https://circuitdigest.com/microcontro...

https://learn.adafruit.com/adafruit-1...

https://singleboardbytes.com/647/inst...

https://www.instructables.com/Automat...

https://pysource.com/2021/01/28/objec...

running python programs at startup: https://www.dexterindustries.com/howt...
(note you have to turn off the camera view in the code!)

Sourcecode:
https://github.com/curiousinventor/sk...