Boundary wire vs wire-free robot mowers
Updated
Among the 65 robot mowers in the Botsize dataset, 11 need a boundary wire and 54 work without one. Wire-free is now the larger group, and it splits into three families with different needs.
| Family | How it finds the edge | What your garden must offer | Models |
|---|---|---|---|
| Boundary wire | A signal in a wire laid around the lawn | A wire pegged or buried along every edge and bed | 11 |
| Satellite positioning (RTK) | Satellite positions corrected to a few centimeters, against a map drawn in the app | Open sky over the lawn, and often an antenna at home | 36 |
| LiDAR | A laser scanner that measures the distance to everything around it | Fixed objects to measure against | 15 |
| Camera only | A camera that tells grass from everything else | A clear border between grass and the rest | 2 |
| Other | A system the maker does not describe as one of the above | See the model page | 1 |
Families overlap. A satellite model often carries a camera to see obstacles, and some LiDAR models use satellites too. The table puts each model in the family that decides what your garden must offer: a satellite model with a camera still needs the sky. 49 models in the dataset carry a camera of some kind.
Boundary wire
A thin wire runs around the edge of the lawn and around each bed or pond, and both ends connect to the charging station. The wire marks the area the mower works inside. Worx asks for pegs about 80 cm apart and the wire 10 cm from an open edge, kept in close contact with the ground (Worx installation guide). Husqvarna lists what breaks a wire: long grass at installation, sharp bends, stakes that rise in soft or dry soil, and stones. It suggests burying the wire 1 to 20 cm deep as an option (Husqvarna support).
- It asks for: an installation along every edge, by you or a dealer, and a repair when a spade cuts the wire. Moving a bed means moving the wire.
- It does not ask for: sky, mobile data or an antenna. The wire works under trees and between houses.
Satellite positioning (RTK)
Plain GPS in a smartphone is accurate to about 4.9 m (16 ft) under open sky (GPS.gov), far too coarse to keep a mower off a flower bed. RTK, short for real time kinematic, adds corrections from a fixed reference: an antenna you mount at home, or a network of stations reached over mobile data. GPS.gov notes that receivers with augmentation can position to within a few centimeters. You map the boundary in the maker's app instead of laying a wire.
- It asks for: open sky over the lawn and over the antenna. Trees, walls and roofs block or reflect satellite signals. Some models need an antenna mounted at home, others work from a network correction service.
- It does not ask for: a wire, or work when you change a bed. Redraw the map instead.
The antenna and sky view guide covers where an antenna goes and how much sky is enough.
LiDAR
A LiDAR scanner measures the distance to walls, fences, trunks and hedges with a laser and builds a map from them. The mower places itself on that map, so it does not depend on satellites and needs no antenna. A lawn surrounded by fixed objects gives it the most to measure against. Makers publish little about how a scanner copes with a wide open field with nothing near the edges, so read the manual if your lawn has no fixed borders.
Camera only
A camera system looks at the ground ahead and keeps to the grass. It needs no wire, antenna or mobile data. It relies on seeing where grass ends, so a lawn that runs into paving, gravel or a bed with a clear edge suits it better than one that fades into a meadow or a neighbor's grass.
Which one suits your garden
- Big trees or tall buildings over the lawn: boundary wire, LiDAR or a satellite model that also carries LiDAR. Check a satellite only model carefully.
- Open lawn, no wish to lay a wire: satellite positioning. Check whether the model needs an antenna at home and where it would go.
- A lawn bordered by walls, hedges and beds: LiDAR or camera models have plenty to work with.
- A lawn that blends into rough grass: a wire or satellite model draws a firm line where a camera may not see one.
- A layout that changes often: any wire-free model. Redrawing a map beats moving a wire.
How the sizer handles navigation
The mower sizer asks whether you want a wire. With "no wire", every model that needs one does not fit. With "wire is fine and preferred", nothing is ruled out and wire models come first in each result group. It also asks how much sky the lawn has. Under heavy cover, a model that steers by satellite positioning alone, without a camera, LiDAR or wire to fall back on, gets the warning that satellite positioning needs open sky. 4 models in the dataset are in that group. Under some trees or buildings the same models get a softer note.
To compare the two directly, see robot mowers without a boundary wire and robot mowers with a boundary wire.