The reason I'm asking this (when it's been asked before) is because I'm playing an Animated Armor, which technically HAS no senses. It's just magic in a shell. (Ghost in the shell, anyone?) So that begs the question, does something that's purely magical have the ability to see through walls? And if so, can it be stopped by that so many feet of wood, stone, iron, and lead? My question is stemmed off of the homebrew race (and the monster) https://www.dandwiki.com/wiki/Animated_Armor_(5e_Race)
Assuming you are talking about 5e-dnd:
A creature with blindsight can perceive its surroundings without relying on sight, within a specific radius. Creatures without eyes, such as oozes, and creatures with echolocation or heightened senses, such as bats and true dragons, have this sense.
The rule doesn't say what blocks blindsight generally, but I would rule it based on the type of sense. Vibration-based senses like oozes may be able to sense through walls and floors, while bats probably cannot sense behind solid walls. Scent-based blindsight may depend on the type of obstruction, with walls more blocking than bushes.
It's up to the DM to decide for the specific creature and environment.