- Reflection sensors send out light and measure how strong the reflected light is. The send out a ray of light and shift the intensity with time, so by measuring the phase shift of the returned light it can estimate distance.
- Time of Flight sensors measure the actual time delta between when the light was emitted and recieved - however this only works if you have very high speed electronics and are working at a scale of a few meters at least, otherwise your results will be uh… less than reliable.
- Ultrasound sensors work like Time of Flight sensors but can send out a big pulse instead of just a ray like the light sensors - which makes it good at detecting very small objects since it doesn’t need to aim right at it.