Far Horizons: Tales of Sci-Fi, Fantasy and Horror. Issue #13 April 2015 | Page 17

Design Flaws of the iRobot
Roomba 500
Andrew Wade
The iRobot® Roomba 500 series is an automatic,
robotic vacuum cleaner (“robovac”). While it offers
completely automatic second-generation robot vacuuming capabilities at a price you can afford, it also
suffers serious design flaws. This document is purposed to enumerate these for the benefit of designers,
investment partners and other stakeholders.
Return to base
The iRobot® Roomba 500 series features the ability to
return to its charging station when its internal battery
runs low. This feature is a direct descendant of the
original Machina speculatrix designs by William Grey
Walter and as such, has not improved much since the
1940s, when it was first conceived.
Its base station beacon and corresponding receiver
on the robot are severely limited as they operate on
near-infrared frequencies and as such can only function in line-of-sight. This, combined with the robots
limited room navigation facilities, makes it possible
for the iRobot® Roomba 500 to become trapped in
another room, hungry and far from home.

power to operate its motors and calling the nearest
human for rescue at the same time. The operator then
has to pick up the unit and place it on the charger
manually.
Room navigation
As mentioned in the previous item, the iRobot®
Roomba 500 series’ room navigation capabilities are
severely flawed. The unit cannot tell the difference
between a temporary obstruction, such as a human
foot or a wheeled swivel chair, and a permanent obstruction such as a sofa or a parked bicycle. It also has
problems perceiving three-dimensional objects such
as bicycle wheels, leading to the danger of the unit
becoming trapped beneath one of the wheels of the
aforementioned vehicle.

1. Elmer and Elsie, Burden Neurological Institute,
1940. See An Electromechanical Animal, Dialectica
(1950) Vol. 4: 42—49

Furthermore, the unit can become trapped in programming loops leading to physical entrapment beneath
and between items of household furniture, i.e. wardrobes, occasional tables, coffee tables and wooden
chairs. While it usually escapes the programming
loops due to the modern software engineers voluntary non-use of the unconditional GOTO statement,
such entrapment can and does waste battery energy
and increase the likelihood of stranding incidents (see
above).

Only being able to use a limited repertoire of movements to escape, eventually the battery becomes
completely drained as the docking light flashes plaintively and the display glows a cherry red of desperation. Finally the robot becomes completely stranded
and plays a sad tune, indicating that it lacks sufficient

Also, the robot cannot logically vacuum the room the
base station is located in last, as it does not perform
adequate room mapping and lacks a long-term memory as such. Instead, the unit vacuums the home room,
then vacuums the room next to that, and so on until
the battery becomes depleted and it attempts to return

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