Ambrogio robotic lawn mower

Some notes on our project to get Ambrogio 15L up and running. We got great assistance from our vendor at Notodden. He always answers your messages. Without him, we would have chosen another maker, like Gardena.

Why Ambrogio? It´s small and can operate in tiny spaces, it´s well built and should be durable. It´s not the cheapest brand around, but it´s used by professional users also. Which should vouch for quality.

If your garden is a rectangle of grass, then count yourself lucky. Otherwise, you will have to modify your garden for the robotic mower to be a success.

cobblestones are about 11×11 cm

Can it tackle a cobbled path or a stone path? Yes. Can it tackle several separate spaces? Yes, but there can only be one perimeter wire, so the spaces must be connected by a single loop of wire. Does it leave a wide margin? No, about 10 cms. Can it handle uneven terrain? Yes, but not so much surfaces that are loose, like bark. Here it can get stuck and dig a hole for itself.

Margin – about 10cms

How does it work?

The perimeter wire probably runs rectified AC, possibly straight DC. DC current runs in one direction meaning the magnetic field has a determined direction, and so Ambrogio knows the difference between clockwise and counterclockwise when it encounters the wire, and can steer accordingly – especially to return home along the wire.

Setting it up

We didn´t buy the garage, but built one out of wood. The model 15 (and probably 20) are a bit tricky to dock properly, and guides of wood on the side are needed to force Ambrogio to dock correctly. Initially it would not always charge. Tried some contact spray and adjusting the guides and now it connects every time.

Home-made garage

Laying down the wire was quite easy, but I would use a tool for burying it if I were to do it again. As it is, it´s held down by plastic pegs every 50cm or so.

Setting up the two separate areas required some talking to the vendor, and it boils down to a 20 cm wide corridor doing the job. Ambrogio can follow (straddle) the wire on one side down this corridor to get from one area to another. In theory, when it´s doing its normal criss-cross cutting it will never hit the 20cm gap and stray from one area to another. In practice this does happen now and then. Making a small bend in the wire at the entrance to the corridor, to make it narrower still at the entrance, might cure this problem.

The corridor: the guide wire is squeezed down, 2 cobblestones apart – invisible here

The knife is 15cm in diameter which sounds and looks tiny, but it works. I have changed the knife after one season, and maybe I´ll manage to sharpen the old one, there is lots of metal left! To change it is very easy.

The robotic mower doesn´t cut the grass by brute force, and hates twigs, wood, rocks and the like: it´s more like a razor than anything else. The lawn must be “perfect”. This also means it´s not fond of tall grass. It´s designed to cut 1-2 cm of incremental growth since last time it passed. Tall grass bends under it and is only partially intercepted by the knife. So if you are away for two weeks and Ambrogio has been stuck under a bush for 13 days, you can´t really set him to work again until you have, er, mowed the lawn!

You also need a tool for cutting the margins of the lawn.

Finally, there is the app. It´s not hyper-intuitive, nor is it bad, and it´s reliable. One thing that I miss is the ability to toggle auto-mode on and off. That has to be done by a physical button.

This leads to the following situation: you program the schedule in the app. You wait for the time to come up. Ambrogio doesn´t budge. After a while you realise you have to push the Auto-button on its top, and then it goes to work…

Nice result

Ambrogio manages this passage the following way: every day when he starts working, he follows the wire a set distance, which ends at the end of this section. Then he starts to work and zig-zags his way back out.

About 60cms wide

Finally, if you have a bush or something, you lay the wire around it and thus Ambrogio avoids it.

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