Roomba vacuum robots are great, but I got tired of my Roomba attacking my cat's food and water bowls. I used the “lighthouse” Roomba blocking units in the past, but the batteries failed and then the Roomba made a mess. 

This solution is to make 200 mm (7.8 inch) sections that fit together to create a bumper so the Roomba will not enter the cat food zone. Each section is keyed and might need a bit of glue to stay together, but it is a fairly tight fit so the glue depends on your use case. Each of the end pieces has a countersunk section that exactly fits a these large, Command velcro mounting stickers.  This allows for temporary removal for cleaning. 

The installation below has been hit many times by the Roomba and is still solid. Note that a very long version of this wall might need some more Command mounts as the center might not be stiff enough.