Working evenings coming home from work without a light switch where I enter I could have just added that or bought a motion sensor light to make my life easier. I prefer to take the longer way and learn new things and had all the components needed at home to build this myself.
Lights On by Motion Detection (Warning High Voltage!)
Tired of stumbling on shit on my way in the house through the garage with no light switches. Solution light connected to a motion detector.