system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How does a roomba work without damaging itself, such as falling down stairs etc?
gpt
The roomba has proximity sensors and spends its time mapping the room. It knows where hazards are and can avoid them. Just don't pick them up, or they might accidentally fall down stairs if it's not where they expect itself to be.

And yes, they do actually clean, although not as well as a traditional vacuum. It's good for a daily cleaning so that dirt doesn't accumulate, but it won't get rid of deeply embedded dirt.