could you use your laser set up to determine if a car has entered a car park or garage for instance? that is, the laser is cut on entry and then established after the car has passed. in doing so, could you distinguish between a car and say a person breaching the laser?
You should be fine with most sensors as your application is indoor and short range. Search for laser or photoelectric retroreflector sensors. Find something in your price range.
😳... Why wouldn't you just use a old laser garage door sensor with the Arduino? Great that it works but just in the future if you're going to build a garden cart on a budget you don't have to design and build the wheels 🙄 You can just grab them off something else.
