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1.8 Defining Obstacles-Perimeter Islands
Many obstacles can be left in the lawn without consideration to excluding them using the perimeter wire.
The basic rule of thumb is that the obstacle must be at least 6 inches (15 cm) high from the ground and the
obstacle must be relatively rigid. Good examples of these kinds of obstacles include many trees, phone
poles and power poles. When obstacles like this are encountered in the lawn, it is easiest to allow the
Robomow to bump into them, causing the bumper sensor to activate and assist in navigating around them.
Young, sapling aged trees are not good examples, as they are not very rigid. Other obstacles that are not
rigid and at least 6 inches high (15 cm) must be protected from the Robomow using the perimeter wire.
This is done as part of the setup process and is commonly referred to as a perimeter island. Good
examples of these types of obstacles are flowerbeds, islands, small trees and low bed edging.
The Robomow is designed to easily work in the lawn with both types of obstacles, however, for the most
gentle and silent operation, it is preferable to demarcate all fixed objects in and around the working area. If
you are unsure about a particular obstacle, it is best to exclude it with the perimeter wire. It will have no
effect on the efficiency of the mower and can later be removed if not needed.
To create a perimeter island, take the wire from the perimeter section closest to the obstacle and peg the
wire around the obstacle, returning back to the same spot of the perimeter. There are two keys to setting
up the perimeter wire to exclude an obstacle; 1) place the wire going
to
the obstacle from the perimeter
and the wire going
from
the obstacle to the perimeter adjacent to one another. This area is between the
obstacle and the normal lawn edge where the perimeter wire is set up; and 2) follow the direction of
installation when going to the interior of the lawn to exclude an obstacle. While the picture in figure 1.12
may appear to have the wires leading to and from the island set up with a space between them, this is for
illustration purposes only. A proper placement of these two wires is to have them touching one another,
but in no event should they be farther than 1/8 of an inch (3 mm) apart from one another. For the best
results, place both wires under the same peg when placing them in the lawn around obstacles. Placement
of the wires as described allows for the signal in the two wires to cancel, but only in the area where they
are installed adjacent to one another and touching. By canceling the signal in this section, the Robomow is
free to cross this area but will still recognize the signal of the perimeter island. See Figure 1.30.
Perimeter
wire
Flowerbed
While the picture shows two
wires separate, they should be
adjacent and no more than 1/8
inch (3 mm) from one another
Perimeter switch placed at least 3 feet
(0.9 m) from perimeter. Wires to
perimeter switch should be placed
adjacent, the same as wires leading to
an obstacle.
Direction of
set up
Figure 1.12 – Excluding Obstacles With the
Perimeter Wire
Direction of set up
followed around
obstacle
