It won't be an issue. I have a Roomba 535 and it routinely travels from the dining room to the kitchen, which requires mounting the new kitchen floor that is 3/4" to 1" (depending on the side of the doorway you are on :)) above the dining room floor. Been meaning to install that threshhold for about a year now. . .
As it is, it's a completely vertical square-off hard surface obstacle.
If Roomba heads straight-on into the transition, it will bump it with the forward obstacle sensor, and turn. But if it approaches from an angle, there is just enough space for the new floor to squeek under the bump bar, and then Roomba will climb into the kitchen.
For a carpet I can't imagine a problem.
When you first use a Roomba, you get a sense that the design process over the years has been very intense with a LOT of testing and customer feedback which led to improvements.
Have you seen the wheels on a Roomba? They are about 2" in diameter, solid plastic wheels with checkerboard rubber for tread. They are deeply recessed into the body, on spring-loaded swing arms which probably balance about 90% of the body weight, with on-wheel drive motors. They are either stepper motors or they integrate some kind of optical rotation sensor, because Roomba can run kinds of complex patterns.
When you put it in spot mode, the growing spiral pattern is impressive enough when you watch the machine trace its previous revolution perfectly, incrementing the radius. Then when it hits long obstacle on a tangent, turns outward, and retraces the next redius increment in the opposite direction, you are all
