This week I had the sad job of sending my beloved robot lawnmower back for service and upgrades. There is a lot of technology around the house, some of it even useful. The lawnmower is one device that just does its job and makes few demands on us other than to keep it clean. It has been a cold and rainy week and in truth the machine would be hiding in its garage all the time.
Like our neighboors, when we moved to this rural area we spent a lot of time outdoors cutting the grass. We have a small lot compared to some, but keeping it looking neat was not a small effort. Letting part of it go wild helped a bit, we now see wildflowers and attract a lot more birds than the prior suburban expanse. But the idea of having a robot keep it neat was very interesting, so four years ago we dived in.
At that time, there were two product lines available — the Lawnbott (made in Italy) and Robomower (by Friendly Robotics, an Israeli company). From a functional perspective they seemed similar — but the Robomower was about 4x the size of the Lawnbott Evolution and from the specs was much noisier. Both could be run like a traditional lawnmower, but the Evolution could also run autonimously. Since my wife works a crazy schedule — sometimes days, sometimes nights, there was a real benefit to a quiet machine that could run itself. And there was an interesting difference between them, besides noise level — in what happened when they encountered unexpected obstructions.
Both machines use a perimeter cable to define the mowing area. This cable is followed when they are heading back to the barn to recharge. There should never be an obstruction on this path — but sometimes there is. When the Evolution hits an obstruction, it backs up and makes a wide circle around it and continues on its path. This seemed to be a reasonable approach. But Robomower in the same situation just backs up and hits the obstruction and keeps doing this untill the obstruction gets out of its way. From their country of origion these differences in behavior seemed symbolic — and the world being what it is the decision to go around the obstruction seemed to be much more reasonable than just hitting it over and over.
So we are into our fourth year with the machine. In the Spring we put it out and turn it on. There are always a few new pot holes and other issues to be fixed — and when the grass is wet and the ground muddy it can get stuck. But for the most part it just cuts the grass as often as needed and we get to do other things. The robot wanders across the yard and cuts what is there. On a typical day we can get 4 to 5 hours of work on a single charge. When the battery runs low it heads back to the barn to recharge itself. Depending upon the state of the grass it may be out again later or wait untill the next day (or longer). The really clever thing about it is that it measures the power consumption of the cutting blade. The more power it takes per unit time then the more the grass has grown. When the grass is not growing very fast the robot reschedules itself to cut less often. This is a very different philosophy from how a human would do it.
Here in our rural area cutting the grass is a major activity for our neighboors. Saturday morning is filled with the chorus of lawnmowers — mostly big riding mowers or tractors with cutting heads. The roar is depressing in an otherwise quiet area. Big, powerful units are needed to cut the weeks’ growth. Robomower seems to follow the same approach. The Lawnbott takes a different tack — it is small and light and works by nibbling away regularly, mulching the grass in tiny pieces. In the years we have been using it this seems a good approach and is not very intrusive. We wish our neighboors would have the same consideration.
The down side of it all is that like most technical wonders it requires a technical touch to keep it going. On a weekly basis one has to keep it clean — the underside cruds up with grass at an amazing rate, probably because the Spring grass grows rapidly and is generally wet. There are error messages when there are problems, but it would get tiresome if we had to ship it off to Montreal every time there is a problem. So as much as I would like, my neighboors are not likely to get one soon. The predicted life for this robot is 7 to 10 years with likely one battery replacement. We are starting our 4th year so this seems reasonable. COmpared with perhaps twice that for a gasoline rider mower. But in our minds the real tradeoff is simple — we dont have to do it. The few hours that I spend cleaning it and sorting out the occasional technical issue are an acceptable tradeoff compared with the hundreds of hours I would have spent cutting the grass myself. But it will likely be many years before the robustness of the technology catches up. In the meanwhile, we hope that we can continue to afford this wonderful device — it has made our rural life far more enjoyable. Unlike so many peices of technology, it just does its job.