I found this old Roomba iRobot and it was quite nice inside so here are the photos

You can find a list of the top vaccum robots around at the bottom (iLife A4s Monoprice Strata Smartvac 2.0 Samsung Powerbot R7070 LG Hom-Bot Turbo+ iRobot Roomba 690 iRobot Roomba 960 EcoVacs Deebot N79 Eufy RoboVac 11)

the brushing system

The Roomba iRobot control unit

These pcbs is very nice and well-designed. the engineers of Roomba have done a good job

Some of the favorite Vaccum Robots around
iLife A4s

Monoprice Strata Smartvac 2.0

Samsung Powerbot R7070

LG Hom-Bot Turbo+

iRobot Roomba 690

iRobot Roomba 960

EcoVacs Deebot N79

Eufy RoboVac 11