A Lawnmower That Looks Where You’re Going

As a kid, one of the stories my dad told me was about mowing a fairly large field of grass on the farm with a gas-powered push mower. One day, some sort of farm tool was left in the field and the old industrial mower shredded it, sending a large piece of sharp metal hurtling toward his leg. Luckily for my dad, the large plastic wheel managed to stop the piece of metal, destroying the wheel. My grandfather was frustrated that he needed to repair the lawnmower but was grateful that my dad still had both feet attached.

Of course, this story was used as a lesson for me not to gripe about having to mow the lawn when it was my turn, but there was also the lesson that lawnmowers can be dangerous. [DuctTape Mechanic] took it upon himself to see if he could prevent that sort of accident altogether and has created an automatic safety shutdown mechanism for his family lawnmower. (Video embedded below.)

This uses an inductive sensor that can detect metal before it gets sucked into the mower itself. The sensor trips a relay which forcibly shuts the mower down by grounding the ignition coil. While it doesn’t physically stop the blade like other safety mechanisms, it does prevent a situation from escalating by turning off power to the blade as soon as possible. Getting to the ignition coil wasn’t easy as it required getting deep into the engine itself, but now [DuctTape Mechanic] has a mower that could be expanded further with things such as with a capacitive sensor or more smarts to determine if it is detecting underground or above ground metal.

Someday we’ll have robotic mowers, but until then, we laud the efforts of hackers out there trying to make the world a little safer.

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DIY Lawnmower Doesn’t Cut Grass Short

[nodemcu12ecanada] is serious about saving water, which is why they built this strange lawnmower that can cut grass taller.

Short lawns are one of those clever marketing victories, like convincing people to eat a lot of sugar, that’s been doing more harm than good ever since the victory was won. Short grass is weak grass, with shallow roots, weakness to weeds, and a lot of water requirement. On top of that the grass is always in a state of panic so it grows extra fast to get to a more “natural” height. It’s great if you want to sell fertilizer, seeds, and lawnmowers. Maybe not so great for the environment.

Most lawnmowers can’t even be set high enough for healthy grass so [nodemcu12ecanada] took three electric weed whackers and bolted them to an angle iron frame. It has a lot of advantages. It’s light. You don’t need to sharpen a blade. It’s quiet. It’s electric. It’s strange appearance will scare your neighbors off from borrowing any of your tools. We love it!

High-Speed Camera Plus Lawnmower Equals Destructive Fun

I hate gratuitous destruction videos. You know, the ones that ask “what happens if we drop a red-hot ball of Plutonium onto a bag of Cheetos?” There’s a lot of smoke, flames and a big pile of ad revenue for the idiots behind it.

This destruction video is a little different, though. [Tesla 500] wanted to mount his high-speed camera onto a rotating blade, but without destroying the camera. In this video, he documents the somewhat nerve-wracking process of building a rig that spins a $3000 camera at several thousand revolutions per second minute. It’s all about the balance, about building a rig that balances the weight of the camera and the blade properly at high speed.

It took several attempts to get it right, and [Tesla 500] shows how he tested and refined each version, including shifting weights to account for the different densities of the camera itself, which has the heavy batteries at one side. And then he drops things onto the blade to see what they look like when sliced. Naturally.

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Where Are The Autonomous Lawnmowers?

It’s impossible to know when society began to manicure its front lawns. Truth be told — cutting the grass was, and still is a necessity. But keeping the weeds at bay, trimming, edging and so forth is not. Having a nice lawn has become a status symbol of modern suburbia all across the globe. When the aliens arrive, one of the first things they will surely notice is how nice our front lawns are. This feature of our civilization could have only been made possible with the advent of specialized grass-cutting machines.

reel mower
Reel Mower [Public Domain]
It could be argued that the very first lawnmowers were live stock. The problem was they were quite high maintenance devices and tended to provide a very uneven cut, which did not bode well for families striving for the nicest front lawn on the dirt road. Coupled with the foul odor of their byproducts, the animals became quite unpopular and were gradually moved out of site into the back yards. Other solutions were sought to maintain the prestigious front yard.

The first mechanical lawnmower was invented in 1830 by a man named Edwin Budding, no doubt in an effort to one-up his neighbor, who still employed a Scythe. Budding’s mower looked much like today’s classic reel mowers, where a rotating cylinder houses the blades and rotates as the mower is pushed forward. Budding was granted a patent for his device by England, much to the dismay of his fellow neighbors — most of whom were forced to buy Budding’s mower due to the fact that everyone else in the neighborhood bought one, even though they weren’t actually needed.

By the early 1930’s, the cold war started by Budding and his neighbor had spread to almost every front yard on earth, with no end in sight. Fast forward to the modern era and the lawn and garden market did 10 billion in sales in 2014 alone. Technological advances have given rise to highly advanced grass-munching machines. For smaller yards, most use push mowers powered by a single cylinder IC engine. Many come with cloth bags to collect the clippings, even though everyone secretly hates using them because they gradually fill and make the mower heavier and therefore more difficult to push. But our neighbors use them, so we have to too.  Larger yards require expensive riding mowers, many of which boast hydrostatic transmissions, which owners eagerly brag about at neighborhood get-togethers, even though they haven’t the slightest clue of what it actually is.

Us hackers are no different. We have front lawns just like everyone else. But unlike everyone else (including our neighbors) we have soldering irons. And we know how to use them. I propose we take a shot-across-the-bow and disrupt the neighborhood lawn war the same way Budding did 85 years ago. So break out your favorite microcontroller and let’s get to work!

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Converting A Lawnmower Engine To Run On Compressed Air

Our most likely exposure to a steam engine these days will probably come courtesy of a railway locomotive. A machine capable of immense power and probably with significant complexity and engineering  in its construction, something the majority of us will only ever be able to see at second-hand. But there was a period when steam engines were much more accessible, before internal combustion engines and electric motors took on the task of automating hard work you would have found small stationary steam engines in all corners of industry.

These engines are on a scale much more easily embraced by hackers and makers, and though vintage stationary engines are thin on the ground these days there are a significant number of people pursuing their construction by converting modern petrol and diesel engines to a more old-fashioned medium.

[Lindsay Wilson] has a lawnmower engine which a few years ago he converted with the addition of a sleeve valve to run on compressed air. It’s not a steam engine because creating a safe and legal steam boiler is an expensive process, but despite this it amounts to the same thing. The engine in question is a small sidevalve single cylinder Suffolk Punch lawnmower engine from which he has removed and blocked the valve gear, and added a sleeve valve powered by a linkage from the crankshaft and using the spark plug hole as an inlet and outlet. He provides a lot of detail on the sleeve valve’s construction, and it really is a surprisingly simple arrangement. We might look for a harder metal than copper pipe for the guide in which it runs though.

The video below the break shows the engine being run up after a period of storage. It’s an effective device, easily capable of taking more air than his compressor can supply.

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Reverse Engineer Your Robot Lawnmower

Your home is your castle, and you are king or queen of all you survey. You’ve built your own home-automation system from scratch. Why would you possibly settle for the stock firmware in your robotic lawnmower? [Daniel Wiegert] wouldn’t either, so in Project Landlord he has started to reverse-engineer it.

You can hardly blame him. The Worx Landroid‘s controller board uses an NXP LPC1768 ARM Cortex-M3, and the debug pins are labelled on the backside. The manufacturer didn’t protect the flash memory. It’s just begging to have its firmware dumped. So far, [Daniel] has managed to both brick and unbrick the device, and has completely mapped the controller’s pinout, so he’s on his way to complete control.

Right now, he’s got a working proof-of-concept firmware on his GitHub that’s able to drive the machine around a little bit and set the brakes. It’s running FreeRTOS, and [Daniel] is looking for other people to get in on the project. He’s done the hard initial work, so get in there and reap the rewards! Just don’t neglect to remove the blade before custom firmware.

Will custom firmware in a robotic lawnmower change the world? Probably not. But it is awesome, and will certainly make a difference in the lives of people whose robot mowers continually get stuck behind the hydrangeas.

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RC Lawnmower Has No Grass To Cut

They say laziness and necessity is one of the greatest drives for invention. Whoever said that didn’t think about what happens when inventors are bored. [The Random Mechanic] decided to build himself a remote-controlled lawnmower, despite the terrible drought he’s been having — resulting in literally no grass to cut.

To make the lawn mower remote-controlled, he cobbled together a gas lawn mower, with the remains of an electric wheelchair. This ended up working really well. He’s using an old RC car remote and its two servos to remotely control the original wheel chair’s joystick. Simple, but super effective.

The wheelchair mower is fast, nice and heavy thanks to some lead acid batteries, and very maneuverable with the front wheels being casters. It’s a shame he doesn’t have any grass to cut!

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