How Pool Robots Find Their Way

A robotic pool cleaner doesn't know your pool. It can't look at a plan or a photo. It drives, it bumps or senses something, and it changes direction. That simple loop, repeated, is the idea behind how they cover a floor.

The controller is a small chip

Inside the robot sits a small computer chip. It runs the drive motors that turn the tracks. According to Wikipedia, the chip makes the machine change direction when it reaches a wall or the water surface after climbing the pool walls.¹

So the robot's whole "plan" is a set of rules. Go forward. Meet a wall. Turn. Go again.

Bumping and shifting over

Wikipedia says some machines may be directed by sensors in the bump bars. It also describes a reverse in direction with a small offset, allowing the machine to move one machine's width over on each crossing of the pool.¹

That's the idea behind lines and zigzags. It isn't magic. It's a turn plus a sidestep.

What a patent and a maker say

An older patent describes a gyroscope-guided cleaner that follows a series of straight lines, giving a zig-zag pattern. It also says that design must be oriented at a prescribed starting point.²

Maytronics says that rather than moving at random, its robots follow a systematic pattern. It says onboard sensors guide the robot along a systematic cleaning path.³

Maytronics also says every robotic pool cleaner cleans the pool floor, including corners, crevices, and the transition between the floor and walls.³

Climbing and turning around

Walls add a second job. Robots that climb need to know when to stop going up. Wikipedia says an internal mercury switch tells the microchip the unit has gone from horizontal to vertical. The robot then changes direction, from ascending to descending, at pre-programmed intervals based on the average height of pool walls.¹

That means the timer is set from the average height of pool walls, as the source describes.

Why the start matters

The patent above says its gyroscope-guided design needed a set starting point.² For where to place your own robot, follow your manual.

What this means for you

Don't expect a robot to "see" the pool the way you do. It reacts to walls, steps and drains as it meets them. Check your manual for how the maker wants the robot set up. If the manual is vague on this point, the maker's support line can answer it. Ask by the exact model name.

Why a robot's route sometimes looks messy is covered in Random and Planned Cleaning Patterns Compared. What each sensor does is in Gyroscopes and Sensors in Pool Robots Explained.