Robomow RX12U The Affordable Robotic Lawn Mower

Unusually for me, I'm going to lead with the price: £499 on Amazon.

I'll just let that sink in.

At that price -- which I'll admit is still a lot of money -- the Robomow RX12U begins to compare pretty favourably with a regular lawnmower.

It looks pretty good, the charging station is low profile, and you even get a natty app so you can talk to it from your mobile rather than having to bend down over a badly lit LCD screen.

Okay, so it won't mow the largest of lawns. In fact, it's limited to something between 150 and 250 square meters of grass.

Part of the reason for this limitation is that it can only mow for an hour and a half before needing a full 16 hours to recharge itself.

And, obviously, with these limitations, it also prefers a squareish lawn without too many complicated turns. Otherwise, it's going to miss areas repeatedly, and result in an uneven cut. The grass, in the growing season, can get quite unruly after only a few days.

Still, the result on a regularly shaped lawn of about 200 square metres is likely to be pretty good. The novel design means that it will go over the edges, too, so you'll get a crisp finish. Just make sure that you follow our Perimeter Wire Tips and Tricks, to get the best results.

Specifications and Installation

For the technically minded, the cut is provided by a single blade, and replacing it doesn't look to be a cheap: going purely on the price of blades for other models (the RM, for example) they seem to cost between £35 and £60. They do, however, look pretty solid, unlike the Indego and Automow (Flymo) variants.

Installation looks easier than most, too, since there's no return wire, and the docking station just sits on the perimeter wire. Now, when it comes to fault finding, I'm a big believer in using the return wire to test for breaks in specific sections (see The Perimeter Wire Revisited), but there's no reason that you can't use the perimeter wire loop instead, for small lawn areas.

One key drawback is that there's no anti-theft device fitted on the RX12 series, which will concern some people: especially as it doesn't seem to be locked to the base unit either, like some of the other brands, and doesn't need to be unlocked with a PIN, either.

Robotic Mower Alternatives

So, aside from building an Arduino based robotic lawn mower yourself (by the way, that's not a cheap option, which I'll explain in a future article), what are your alternatives?

It turns out that if you're willing to go with an older generation, admittedly bigger, bulkier (and uglier) than the little Robomow, for £100 more, you can get the Flymo 1200R.

Here's some advantages: the blades are cheaper to replace, there's a full anti-theft device (beeping, PIN codes and coded base station), it has a guide wire, so you can tell the mower to start at a specific place, and it can always find its way home, and it doesn't need 16 hours to charge.

In fact, our Gardena R40Li, which is the same machine, doesn't seem to need much time at all to recharge, and is almost constantly buzzing quietly around the lawn. Okay, so it's based on the Husqvarna Automower 105 style technology, but there's on big advantage that comes with it: Husqvarna invented the mass market robotic mower, and is still probably the market leader in Europe by some margin.

So, if you have a small, enclosed, secure lawn, go for the Robomow. Otherwise, that big orange robot represents a very good alternative, and at almost half price on Amazon may just be an opportunity that's too good to miss!