Latest El Reg project: Rise of the Robot Sheep

After seven years of faithful service, my lawn-clipping droid Mowbot has had to be retired... and a replacement is hard to obtain. Rather than face an ever-growing lawn, I've decided it's time to unlock the inventing shed and seek some reader advice. Robots were supposed to be doing pretty much all our manual labour by this …

[Chazmon]

If spinning blades are a less preffered option may I be the first to suggest fire?

I imagine a systematic flammable liquid spraying system followed by remote ignition and voila your grass is considerably shorter and neighborhood cats are as an added bonus probally going to avoid your garden for a while. Would need to be done less regularly than the conventional method therefore less maintenence.

[Elmer Phud]

Cat Sensor

Adding a cat sensor similar to those used for some cat flaps could also mean avoidance of the family moggie but dissuasion with predjudice for the rest of the local felines.

Yes, it's also the old joke about how you get a cat to go 'woof!'

Flameproof coat to hand . . .

[Anonymous Coward]

I like it!

The only way that could be improved is if it could also cover the garden with six inches of concrete to save on future mowing related expenses.

[ian 22]

Building on your suggestion...

Add the 'errant youf recognition' capability with the 150 decibel "GET ORF MOI LAWN!" message, connected to fire breathing capacity and flailing blades. World + dog will beat a path to your door (if they can get past the flames).

[Stoneshop]

Fire

Ah, the Burt Munro method

[Christoph]

Navigation

Equip the thing with a cheap cell-phone camera, use existing software which can locate and read bar codes or QR codes to find the codes stuck on a few things round the garden. Then triangulate off these. Should give you very accurate positioning.

[dotdavid]

Cellphone

As modern smartphones are basically portable computers full of useful (and not-so-useful) sensors, maybe have one of those with the appropriate software as the brains of the device.

[Vic]

> maybe have one of those with the appropriate software as the brains of the device.

You can do lots with a phone.

http://www.youtube.com/watch?v=_d0LfkIut2M

Vic.

[Mike Manes]

Sonar navigation

The buried wire is an elegant method, but it does incur some sweat equity, and after all, isn't that what we're evading here? The idea of using a mower-mounted camera an QR signposts is a great alternative that allows one to program alternate mowing patterns to avoid embedded streaks.

But it also requires some sophisticated optics, and could get foiled by obstructions such as trees.

I'd propose another alternative navigation system which retains the programming flexibility of the QR code / camera scheme, and that would involve planting ultrasonic transponders around the yard, and triangulating based on the time delay from the mower's interrogation "beep" to the receipt time of the transponders' response beeps. The slower acoustic propagation velocity will allow for high-precision location determination without requiring nanosec timing measurements.

Beacons could be identified by unique ultrasonic frequencies, and use of parallel -channel DSP could be applied to time-of-arrival determination. And the physical layer hardware would be trivial to implement. Beacons would require little power, and could run indefinitely given small solar panels.

[DJV]

Also...

Will it have a container for the clippings and, if so, then, when the container is full, can you get it to locate the compost bin (even if I have to stick one of Chistoph's QR codes to it), climb up it, remove the lid (optional, I may possibly be capable to remembering to do this before starting the mower) and deposit said clippings in the bin before carrying on where it left off?

[Svantevid]

"I've decided it's time to unlock the inventing shed and seek some reader advice."

---

Is Mr. Travaglia unavailable, down under in Aotearoa or some similar place with more vowels than is healthy? He obviously has more devious mind than your average El Reg reader, and if I ever wanted to build a killer robot I'd contact him immediately.

[Rob]

What about....

... a laser cutter for the grass and also a water pistol than can fire a stinging jet at unwanted cats, just don't get the 2 the wrong way round.

[Anonymous Coward]

Hot wire

How about using a hot wire to cut the grass? That is until light sabre technology is available.

[Eddie Edwards]

Roomba

Can't you take a roomba and add some kind of internal blade thingy to make it cut grass?

[Doozer]

I tried changing roombas sweeper beater bar for a home made cutting bar... Only problem was that the missus wanted to hoover the hallway, didnt realise what I had done and shredded the carpet.

I was in the dog house and relegated back to hoovering again after converting her precious robo-sucker.

[Alfie]

Surely you could strap a mower to the front of Stephen Hawking's wheelchair. That would have enough power and weight to push stuff around, and it's covered in tech, so presumably it could be controlled remotely?

BTW I'm not condoning the hijacking of the Prof himself, but what the hey, he's not got anything better to do, and he could do any work remotely over the Wifi link while trundling around the lawn.

[Carl]

Ive got one.

General-purpose Autonomous Oral Turf-destroyer.

or "GOAT".

Works great. Doesnt even need lecky.

[Kevin Johnston]

Nice idea but.....(or butt even)

Goats only eat grass as a last resort which is fine if that is the only thing in the garden even remotely edible (be aware that goats consider anything they can fit in their mouth as edible).

[Audrey S. Thackeray]

Goats prefer to eat anything they believe you value so what's needed is a way of convincing goats that long grass is treasured even more than roses and laundry.

[Stoneshop]

@Kevin Johnston

Still, they're to be preferred over sheep. Goats clip the grass (provided they can be arsed to do so in the first place); sheep rip out the grass, roots and all. They're the bane of the still-arable regions around the Sahara

As far as I'm concerned, goats taste better too.

[Steven Roper]

@Stoneshop

You've got that the wrong way round mate. It's goats that rip the grass out by the roots, whereas sheep only crop the grass. I know because every couple of years or so we go out feral goat shooting up at my mate's farm because the bastards destroy the sheep paddocks, and it sure as hell ain't the sheep that do the damage. In fact even the roos do more damage than the sheep!

At the Gorge Wildlife Park near Adelaide, there's an even more vivid example: a series of small paddocks or large enclosures, each containing a few specimens of one type of animal. The one with the goats has been eroded down to more than a foot below ground level across *every square inch* of the enclosure. No other animal does this so destructively.

[Stoneshop]

@Steven Roper

That's because you're down under. Crossing the equator flips goat and sheep around.

[Anonymous Coward]

General-purpose Autonomous Oral Turf-destroyer is GAOT, not GOAT!

Try General-purpose Autonomous Over-engineered Lawnmower, and you may well end up GAOL if you follow too many of the suggestions in these comments!

[Anonymous Coward]

GAOT? That acronym

Blows Goats, I have proof

[Pete 2]

KISS

It sounds like you have already nailed the First of Larry Wall's Three Great Virtues of a Programmer (i.e. Laziness, for the truly lazy the other two are Impatience and Hubris - give yourself a a pat on the back for not bothering to look them up).

Impatience should require the use of Off the Shelf parts - possibly an ideal opportunity to buy a Raspberry Pi if/when they ever become available.

As for Hubris, I'd suggest giving the Mk2 it's own web interface, plus real-time webcam feed.

However, going back to Laziness for a minute. I don;' feel that having the device controllable from a phone or PC quite does it, for the truly lazy. Surely the object of complete laziness is for the device to do everything itself? Possibly up to and including re-ordering it's own SLA batteries when it detects the current ones are failing (shades of 2010 A Space Odyssey:, perhaps? Just keep it away from hard vacuum.).

One final point on the topic of a cylindrical cutter. Check out the blades that woodworkers use in planer/thicknessers. Apart from being scary sharp, really: SCARY sharp, they could be the sort of thing you'd be looking for. With a few adaptations, the Mk2 might even keep your hedges in trim.

[jai]

spinning blades are so imprecise

no matter how sharp your stanley blades are, and how fast or slow your spinning plank of wood, you'll never get all the grass at the same height.

So I suggest the use of lasers and small mirrors from the outside of a disco mirror-ball. position the mirrors all around the circumference of your lawn (reflective side inwards). Then set up one of those military spec lasers at the desired height on the top of a spinning lawn waterer gizmo. Switch on the spinning, switch on the laser, and presto, uniformly cut lawn. just make sure the lawn is empty before you begin the process, no responsibility will be accepts for any cats missing their paws below the kneecaps.

[TonyHoyle]

Lateral thinking

A strip of monofilament wire anchored at both sides of the lawn. Press button, wire cuts lawn in 2 seconds flat.

Only downside is it'll do the same to pets, family members, etc. if they get in the way.

[jubtastic1]

Clippings

Emptying into a compost heap seems like it could get complicated, but how about interchangeable hoppers so it could simply drop one off when its full and pick up another, leaving the owner to empty the hoppers. These coud be combined into a drive through charging dock/kennel.

[Stoneshop]

The job for

Special Projects Burro?

[Dan Paul]

Do Androids Dream of Electric Sheep?

I for one want to be the first to welcome our new electronic Ovine Overlords.

May I suggest using a modified electric hedge clipper? Might be safer than whirling blades.

Also, tons of images and info on "Electric Sheep" on the web including life size Japanese robots with real wool.

FWIW, Arduino, Arduino, Arduino.... you won't have to reinvent the sheep!

[Evil Auditor]

Get a sheep!

Sheep eats lawn. Bill eats sheep.

[Peter Gordon]

In the spirit of Reg projects

named after classy ladies (PARIS, LOHAN), may I suggest:

Mowing Automatic Robot System Hack

(after Jodie Marsh)

[Jason Bloomberg]

Classy ladies?

SLAGS - Server Linked Autonomous Grass Strimmer

[Graham Marsden]

NAOMI

New Automated Optimised Mowing Invention

[Mike Moyle]

May I humbly suggest...

...the BRAZILIAN -- the Basic Remotely Accessed Zone-Inscribing Lawn Inhibitor And Network -- when you want to keep your lawn neat and tidy.

[Mako]

@Mike Moyle

That is utterly full of win!

[Locky]

Surely this is the name of the 2nd part of the project, the automatic bush trimmer?

[Anonymous Coward]

Gentlemen..

Heuristically Operated Lawn Leveling Yard Wandering Ovine Outdoor Device

or, HOLLYWOOD

Designed to efficiently and throughly remove grass from the front garden to the back garden.

[Mr Young]

That's enough!

Do you need to eat or something?

[Vic]

So I'm not the only one...

... Who's been looking for an excuse to buy a BigTrak :-)

Vic.

[Monkey Bob]

I nearly "accidentally" bought one while Xmas shopping online the other week, plus the £16 rocket launcher attachment.

Now I think about it why didn't I buy one? Damned fool.

[Mystic Megabyte]

Clippings, what clippings?

I have a John Deer self-propelled petrol mower that mulches the clippings.

In the right conditions it works very well although the build quality is crap.

It works best if the grass is dry and you only try to trim 1½" off the lawn.

The secret sauce is in the shape of the blade, it has a couple of twists on the trailing edge which AFAIK pulverises the clippings to dust.

The grass here is usually wet and too long so I'm working on the laser cutting version with mulching after-burner.

Laser Actuated Remotely Driven - Android Slave System?

[Swarthy]

OVINE

OVINE: Verdure INhibiting Engine?

Or, if using the luminous methods above: "Phillip" - Pulsed High-Intensitiy Laser Lawn Inhibitor Prototype. 'Cause who else would you name an electric Sheep after?

[Anonymous Coward]

Idea's

Proximity sensors (Laser against fence all 4 directions) and a pre-programmed layout would give exact position at all times, as long as you tell it never to go out of area, then proxmity sensors on bottom to stop it from hitting things. Set it all up on a RasberryPi with that being the controller. you know I might have a crack at this myself converting an electric one and using an upside down L shaped pole in corner to stop cable snagging.

[NG]

OWL

Over-engineered Wireless Lawnmower

[NG]

iMow

Internet Mower Operating Wirelessly

[Cmas7]

Electrolux where are you

I have had a Electrolux Automower for 5 years. While the iPhone gets out a new version every year and gets lots of interest, this stuff doesn't change. I have been ready to buy an update for the last 2 years but are still using the old one. The first and really simple upgrade would be the necessity of guide wires. The machine already measures how far it goes by counting wheel rotation plus it has programmed direction changes so it know the angles of direction changes. Even without a GPS it should easily construct a map of the lawn, and with todays flash prices keep up to date where it is and have been (sharable by wifi). Second and equally simple upgrade is to get rid of need to reprogram timing between spring and autumn. The machine already measures necessary force on cutter so it should easily be able to find out where grass is growing fastest and visit accordingly and rest when it is not necessary to cut. Thirdly a camera with color analysis should be able to tell where and what kind of fertlizer is missing. Fouth the machine should be able to deliver this fertilizer. Fifth doing the lawn edges would give time to drink even more beer on Saturdays. Electrolux, I am ready any day to test a beta.

[Nada]

PORTMAN

Probably Overengineered Robotic Turf Mowing Autonomous Navigator

[CowardlyAndrew]

Freaking lasers mounted on the head of a squirrel is what I want, and I want it now.

[Swarthy]

An Idea for the mowing

I'm thinking a cylinder wrapped around a rotini-like spiraling blade.

Start with a sheet metal tube, cutting a section out of the tube to make it more of a "C" shape. Line the tube with chicken wire and cover the gap (grass gets in, but not toys, kitties, etc). Have the spiral blades fairly close to the CW. Lining the tube with the chicken wire with a close tolerance for the blades will mulch the grass, so no need to worry about bins, composting, or such.

By putting the tube/grate opening slightly forward of bottom-dead-center, the tube would also bend the grass, making the coveted lines (or words). Or put the tube on a servo, moving the opening fore/aft/center and adjust the whole cutting assembly up and down on the fly and you could program it to do patterns. A happy face, I think, to let all know I am glad I didn't have to mow this.

[Flocke Kroes]

The obvious name is Kusanagi, but I have to start cooking now, so I cannot pick a backronym.

[IR]

Paradigm shift

How about instead of treating lawn mowing as a once-per-week or so activity, treat it as a constant thing. As soon as a blade of grass gets to a certain length, zap the top off with a laser. Constant scanning as a specific height means one or so shots per minute, with some software to avoid shooting larger objects such as children.

[Anonymous Coward]

Arduino(s) FTW.

DGPS should be fine right up to the point where the 'merkins find out somebody has oil and decide the people should be freed from the shackles of their dictatorial regime, hammering the accuracy of the GPS signal on the day they invade (yeah, I know they said they'd not degrade the accuracy again but if they have to pick a fight with someone their own size who knows)

Seriously though, bump sensors and/or ultrasonics for detecting small objects on the grass, a gimballed scanning laser on top with retro reflectors in corners of the grass, a map and a bit of maths should be a fairly good way of working out where you are.

Plus it'd look uber cool on a misty day if you chose a visible laser wavelength.

[Anonymous Coward]

Oooh,

and can I have the duff old one?

[Anonymous Coward]

dreams

when I was a child 30+ years ago, I had a book about the future, jet packs with head up displays, bountiful energy from nuclear fusion, instead we got the solar powered parking meter.

[Steven Roper]

Solar powered parking meters

They're really just solar powered? Awesome. Think of the fun I could have with a thick black texta or a can of black spray paint... ;)

[Boris the Cockroach]

Can I program

it to go on a killing rampage if it gets bored of going up and down your lawn

I would do that to the robots at work, but the boss, rather unsportingly, will fire me for it....

[Peter2]

Wouldn't it be easier to simply start with a lawnmower and fit a propulsion and guidance system?

I mean, no need to completely re-invent the wheel completely. I'd very much like to see the first person with a working model though.

[ElReg!comments!Pierre]

All the lawnmowers I've seen recently actually have a propulsion system (a small electrical motor driving the rear wheels, usually not sufficient to move the thing but easing the work somewhat).

The problem with that plan is that the whole thing will have to be modified so much that it is probably easier to start almost from scratch (of course existing motor blocks can and should be used; that's outside of the gardenshed-boffinry limits). Fitting a propulsion system on something that was not designed to accept one is going to be a major problem in itself; then there is the direction; then you need to get rid of the dead-man security system; etc...

Unless you want to start from one of these assisted-direction little tractor-like things? That would be an easy job (I believe all that would be needed would be to crack the control system for the assisted direction and throttle, and plug it into a control server) but that's going to be a huge machine, and hugely expensive, too.

[ElReg!comments!Pierre]

Obvious choice

The base should be an Oldsmobile Delta Royal 88, modified to run on steam, with big spinning blades at the front.

Also, there is a typo in the article. You typed "avoiding children" when you surely meant "chasing".

More seriously, chasing high grass in real time sounds fun but it is probably simpler to enter the lawn's geometry beforehand and calculate the optimal path (step-wise, should be a doodlewith the right optical encoders), with a sensor to detect obstacles (with path re-calculation of course). Whatever system you use to decide of the path, keeping track of the position by the optical encoder steps, not by triangulation as suggested higher up, is probably the way to go. Of course you will need a calibration step first (so that the control system knows the dimensions of the area in terms of encoder steps), but it will make the programming much easier (basically logo-turtle-like). I know, it's no fun, but it is simple, and in software "smart and fancy" often means "likely to fail". Plus, that will make writing "tasteful" messages (or stripes, for the unimaginative) very easy.

I don't have any suggestion as to which kind of encoder/microcontroller combination would be best, as the one I am working with, although reliable and durable, won't last long in a vibrating, dust-saturated environment. You need some heavy-duty stuff. I wonder what they use in the metallurgical industry...

[Hawkmoth]

of sheep and mowers

I was thinking a reel mower would be safest until I read Dan Paul's idea for a hedge clipper. Either could work and you'd want to go with whichever is easiest to keep at the right height given your lawn's micro-topography and the mower's wheels/suspension. Everyone knows that lawns need less fertilizer if you leave the clippings on them rather than bag and remove them, so that should be your goal. Reel mowers work best if you mow frequently and that would be best for mulching. If you find yourself building up thatch, you'll have to invent a robot aerator/de-thatcher, which could be a lot of fun in and of itself. As to guidance, my first thought was to use a system that triangulates using those mirror balls people put in their gardens. If the robot had a bright light on it, the spherical mirror would reflect it at a very precise point, no matter where the robot was. Use three different color balls and lenses with three different filters to allow the robot to distinguish among them. If the cameras were at the top of the robot pointed up and there were rotating 45 degree mirrors mounted above them, then the camera would get a flash whenever the mirror pointed at its ball. The bearing to that ball could be read from the rotor on the mirror and a computer should be able quickly to determine the mowers location every full mirror rotation. I believe that early IR seeking anti-aircraft missiles used similar devices.

[jmo]

Stripes

The stripes come from the rear roller, NOT from cylindrical blades!

Most (petrol driven, user holds handle at the rear) mowers also use the rear roller for drive because it is heavy and has a large surface area (compared to the front wheels) and therefore traction.

[psylent_bob]

a bot by any other name...

in keeping with the reg ideal of naming spb items after media friendly ladies I humbly suggest:

Generally

Autonomous

Garden

Assistant

[Killing Time]

El Reg Project Naming Convention

How about -

IMOGEN - Independent Mowing Operation Garden Environment Navigator -

There is a 'turk' (south wales expression) 'bint' who meets the criteria of previously honoured ladies of ill repute.

[unreggi]

Recycling

"...but we'll not be recycling any other parts of the old chap any more than we'll be building a chassis out of granddad's femurs. That also means anyone else who wants to have a crack can use our designs without having to buy a Mowbot first..."

That also means...granddad's femurs are still available for your other projects.

[Donald Miller]

Cylindrical? Get reel!

The stripes are left by the roller on the mower, not the blades. My 3 circular blades, 6' total width, are followed by a 6' roller, so I can leave stripes that can be seen from space, but striping is for stupid suburbanites with too much time on their hands. (And I can mow most such yards with one pass up and one pass back, so it's not very well striped.) Meanwhile, I'm composting the clippings back into the yard, thickening the sod.

Reel mowers require a LOT of torque, and are very finicky about being razor-sharp and closely-adjusted against the bed knife. I recommend a flail mower segmented finely, so each section can closely follow the ground, but spinning swords require the least power.

Incidentally, goats have the largest stomach-area/weight ration of any grazer and don't like anything close to the ground, probably an evolutionary adaptation to parasites, so they eat the roses before the grass. And, having had hundreds of ovines, you can only eat a lamb if it has no name. Once the kids name it, it's a pet, not lunch, and you can't house-break sheep. (At least they only leave pellets, about the size of rabbit berries, but they do piss bright yellow.)

[TeeCee]

"...I'm composting the clippings back into the yard, thickening the sod."

Allowing the clippings to remain on the lawn creates what's referred to in gardening circles as "thatch". This causes waterlogging of the surface, which destroys the root mat and kills the lawn.

Compost the clippings elsewhere and dig the results into the flower beds where it'll do some good. Best thing for the lawn is to go over it with a fork, making rows of holes, followed by a light dusting of sand. This then washes into the holes made by the fork tines and improves the flow of moisture through the surface, preventing waterlogging of the root mat.

No, I do not know how I know that.......

[Wilco]

Stripes

The blades don't do the stripes, the roller does, so a rotary cutter won't help.

You need a heavy roller to flatten the grass to give that stately home effect. Or a light roller pushed down with a load of lead acid batteries, perhaps.

[Ministry of Truth]

Get hold of an old flymo

Cause the blades are metal, sharpenable, potentially lethal, and very effective. And they cut in any direction. Might even have an old spare one somewhere...

The cylinder doesn't give you the stripes, and cause it relies on having a second blade to pass against, it one directional and takes more effort to spin.

It's the roller that gives you the stripe, and you'll need to work out a turning technique so not too much of the stripe is lost at the tops and bottoms. But of course rollers will take way more energy to move around.

Mulching is ok, saves collecting stuff, and what about a feeder/seeder to add to it for that really lustrous green lawn?

You can always add a flame job to the paint if it's too lame for you...

How adverse would you be to having the controls electric, but the power from a petrol engine? A little moped engine would give you more than enough grunt to run a 6V circuit too?

[boffles]

think small, think cluster

If I can make a small suggestion. If you are going to do all the hard work off the robot, make small and multiple. If the robots are cheap and dumb, then they are cheap. Bigger lawn more mini bots. If someone should take one, you can much easier to replace then one expensive one.

[StephenC]

StephenC

The stripes are produced by the roller - not by the cylindrical cutter. I have a rotary mower that produces stripes this way.

[Matthew 3]

Yes, the use of a cylindrical blade is normally to cut very close to the ground. It's usually reserved for the kind of mowing associated with bowling or putting greens.

Much as I'd like a lawn that good I think a normal rotating blade and roller will do the job. Although it will also need a strimmer attachment for the edges...

[Win_termute]

Some thoughts

How about buying one of those weed cutters that has a plastic wire spinning at high speed? It should cut grass just fine but probably just convince the owner of any fingers put in it's path that they (the fingers that is) would be better off somewhere else. If you bought a wireless one you would get both a battery and a charger for the lawnmower as well.

As for guidance, how about having the mower emit an infrared pulse every few seconds. You would then have tree strategically placed recievers that would look for their own pulse (one, two or three short pulses, possibly after an initialization pulse to make sure they are looking). The recievers would then emit an ultrasound pulse that the mower would hear. It would then calculate the distance to each reciever. Poor man's gps. It should then be a simple matter to program the path the mower should use.

I agree with previous posts that the arduino would be a perfect fit for this project

[mb2038]

eco friendly ...

what about using some of that high water psi drilling kit to cut the grass; then it gets watered as you work

[evs]

Turf Uniform Reduction Networked Equipment - Reel-type

I would suggest a small reel (perhaps 3" dia 6" long) with guard wires parallel to the rotation and no capture of clippings...basically a Mad Max Dirt Devil. If you make the reel small enough, it won't need enough power to sever toes and whatnot and the guard would let the grass through (and even guide it for cutting) without allowing curious paws to get any more than a manicure.

Or you could put your whirling death machine inside a mesh ball.

[MarkCX]

Why not try...

Guinea Pigs. Forget goats, sheep, rabbits etc. Guinea Pigs will give a nice even cut and fertilise at the same time.

[Richard 12]

They taste good too

Similar to lamb - mmm, cuy...

[ElReg!comments!Pierre]

Brain of the beast

I think the path calculations should be done locally (i.e. hardwired, not on a remote server as suggested somewhere in the article). Remote control is just asking for problems. What if you lose the link? There can be a remote oversight, but the core of the control should be local. Also, for safety reasons, if contact with the remote control channel is lost the mower needs a local system so that it can park itself safely, say, on the nearest Iranian desert*.

I suggest using a Ben Nanonote as the local brain. It's cheap, relatively inexpensive (100 bucks), resilient (I dropped mine a few times while in the tube; it takes 1.5 m falls on concrete -with forward momentum, even- without a complaint), fully copyleft, flashable at will, it has ethernet over usb or can be fitted with a WiFi microSD card (if you can find one). 336 MHz MIPS-compatible chip, 2GB NAND, 32 MB RAM, with a small colour monitor and a full-featured keyboard for in-situ interaction if needed; what's not to like?

http://en.qi-hardware.com/wiki/Hardware-Ben

There's plenty of space to put your -legally obtained- music tracks, so attach a 50 quids sound system from Costco -with a massive subwoofer- to the lawn-mowing core and presto!, you got yourself an efficient neighbour-angerer.

The current shipped image is an OpenWRT with Python2.6, Lisp, 4th, gforth, perl I think, etc (and of course C). Even Octave, the open-source MatLab clone! so it could be used out of the box; of course it's all open source, so the sky (and your cross-compile toolchain) is the limit.

If you keep the microSD slot for wireless comm, the only possible channel to control the mowbot would be the USB port of the Ben (I'm guessing ethernet over usb would be the most convenient way to talk to whatever board is talking to the microcontrollers - and encoders, but what do I know? see disclaimer below). I can submit a tentative circuit board design if needed**. I do know my way around optical encoders, microcontrollers and such, and high-level languages are not a problem, but I have litterally zero experience in linking both through USB, so YMMV, as the cool kids say. The datastream needed is really more a datatrickle, so the Ben's USB 2.0 will be plenty fast. That's a good start, right? RIGHT?

*Nah, just kidding

** Caveat lector: all circuit board designs I might submit will be heavily inspired by pre-existing, proprietary designs belonging to various companies, all of which are long dead -but some might have been bought by Oracle, some of the angles might be rounded, which I hear is patented by Apple, and component colour might involve brown, so beware the Zune patent pool; your status = warned. The designs predate the "patent the obvious" goldrush, which is good, but almost always involve a 386 chip, which is bad. Well, for some values of "bad".

[ElReg!comments!Pierre]

Patch

:%s/cheap, relatively inexpensive/relatively inexpensive/g

# Obviously.

[ElReg!comments!Pierre]

side benefits

There is a nethack port for OpenWRT on the very Ben NanoNote, so in theory it could verily be used to draw your very own nethack levels. On your very lawn. How very cool is that?

(this message sponsored by VerY Inc., proud owner of the "very" trademark. VerY Inc., now a part of Oracle. Expect some rebranding as soon as you're used to the price hike)

[Eddy Ito]

Go ahead with a big cylindrical reel mower. Start with a 36 inch wide snow blower with tracks, change the blades, up the gearing and power it with an old air cooled VW engine. It will sure keep the lawn tidy if the second stage is up to tossing everything, even the neighbors cat, into the neighbors yard.

[Purlieu]

Brazilian ?

No no no, that would mow the lawn clean all over, apart from a thin strip up the middle

[Win_termute]

Some ideas

How about buying one of those weed cutters that has a plastic wire spinning at high speed? It should cut grass just fine but probably just convince the owner of any fingers put in it's path that they (the fingers that is) would be better off somewhere else. If you bought a wireless one you would get both a battery and a charger for the lawnmower as well.

As for guidance, how about having the mower emit an infrared pulse every few seconds. You would then have tree strategically placed recievers that would look for their own pulse (one, two or three short pulses, possibly after an initialization pulse to make sure they are looking). The recievers would then emit an ultrasound pulse that the mower would hear. It would then calculate the distance to each reciever. Poor man's gps. It should then be a simple matter to program the path the mower should use.

I agree with previous posts that the arduino would be a perfect fit for this project

[Tim #3]

One frankly disappointing aspect of the suggestions seems to be the focus on health and safety above all. Daleks et al were not known for being slow underpowered things that have to return to the charging dock frequently, ok so they did take out a few fleshies too but hey. Let’s consider some user requirements that would make the design transferable to a wide number of readers – such as ability to cope with longer grass, slopes, uneven lawns, molehills, fallen leaves, no outdoor electricity supply, and how about a cost ceiling too?

[Wombling_Free]

Combine with HOVERCRAFT!

Blades - design for cutting and LIFT!

Just like the old electric 'FlyMo' things, except with on board energy (electric, IC or nuke, your choice) and completely autonomous.

I think you could get the control gear cheap from Iran.

Semi-autonomous Hovering Electric-Engine-Propeller Flying Under Computed-Kinetic-Error Restriction

[Aaron Harris]

Fuel?

All this talk of binning the cut crass, rather than dump it in the compost bin surely we could utilize the composting process on board to produce heat and therefore power?

Over to the Bi-chemists for the technical stuff.

[John Sturdy]

Other outdoor devices, to get ideas from

Farmboz isn't actually a robot, but has quite a solid mechanical design: http://eirepreneur.blogs.com/eirepreneur/2011/01/irish-made-wonder-robot-herds-sheep-mows-lawn.html and http://clikire.snappages.com/farmboz-3.htm

Slugbot is an autonomous self-feeding garden predator: http://www.wired.com/gadgets/miscellaneous/news/2001/10/47156?currentPage=all and http://www.ias.uwe.ac.uk/Robots/slugbot.htm

[Anonymous Coward]

I am thinking something along the lines of Terrafirminator as featured in Gnomeo and Juliet...

[Hawkmoth]

Re-consider Sheep

You know, you might reconsider the sheep. You could use sheep to do the mowing and build the robot to pick up their poo. You know, something with a dustpan and broom on the front...it'd be cute!

[TeeCee]

Rise of the Robot Sheep?

Tsk, tsk, tsk.

Any fule kno that the correct term is *Electric* Sheep.....

[Stoneshop]

Cylindrical cutter

If you use a separate motor to run the cutting bits, torque to propel the thing around your lawn becomes less of a concern Of course, you still have to deal with the rolling resistance, especially on a sloped lawn, but that's well within the capabilities of a pair of wheelchair motors. Traction of the drive wheels on (possibly wet) grass would be more of a problem.

[alanmcg]

Cutting blades

Why not use plastic ones? I don't mean strimmer wire, I mean plastic blades as supplied for various electric mowers. I use an old Flymo from time to time which has two plastic cutters about 3 inches long. At operating speed they cut very effectively, they eventually break but are cheap to replace and if you hit anything especially solid (rock, free roaming tortoise, fallen over elderly relative..) they disintegrate without causing any visits to A&E.

Getting a good cut seems to require speed more than power. Oh and the lawn needs to be not too wet, a moisture sensor might be good to include.

[alanmcg]

Weight distribution and augmented guinea pigs

Type of mower strikes me as important. If you want a roller to make stripes I guess you'll need some weight over that roller, so engine or battery packs over or behind the roller? (mid-engined or rear engined like a 911 sir?) If however you want a hover motor which has its advantages (moves more freely, look vaguely cool, blows stuff all over the place frightening bystanders) then weight will be a problem. I don't know if they do hover mowers that can do stripes though the old flymo I use does have a roller.

Or you could just use augmented guinea pigs. Strap a lawn cutting jacket to them complete with battery pack, head mounted camera, smart phone brain (might want to avoid using one of the new 4"+ house brick ones) and maybe a frikkin laser beam just because. Then spend your time trying to prevent the neighbours seeing your guinea pig cyborg minions and shopping you to the RSPCA.

[Dangermouse]

Robot Naming

General-purpose Autonomous Over-engineered Trimmer (Special Edition)

[Dalen]

The design looks like something that would be seen on Robot Wars. Maybe go to those guys for hints?

[DanceMan]

Squirrley

If you can invent one with an option that kills squirrels, I'll even plant a lawn. I opted for various shrubs, and trees with ivy as ground cover. Have to use a hedge trimmer to cut the ivy off the walks a few times a year, but it beats having to go out and cut the grass NOW because it finally stopped raining.

Robot sheep? It was done decades ago:

"Voici le mouton Anglo-Francaise!"

[Cliff]

Flat lawn? Laser cutting! Just stand the unit in one corner and run away fast before it turns you into slices. You may wish to mask rabbits, trees etc with tinfoil

Also - make it properly phone-controlled and you can get bored commuters to cut your lawn for you

[Beelzeebob]

Required viewing for builders of electric sheep

Anyone contemplating the building of a remote-controlled lawnmower must first watch Frankenhooker.

Plot Synopsis: Aspiring scientist Jeffrey Franken shreds his girlfriend with the remote-controlled lawn mower he invented. In the ensuing melee he escapes with her head and stows it in his garage laboratory. He then embarks on a quest to acquire perfect parts to rebuild her body. Where does one get perfect female body parts? Where else but from prostitutes? The inevitable conflict between the good girl’s brain and all of those bad girl body parts results in the rebuilt girlfriend hanging out on street corners uttering the immortal line "Wanna date?" There’s much more, all of it a hoot. Highly recommended.

[Robert Heffernan]

My Idea

Here's my idea.

A tracked platform containing a reel type mowing assembly powered electrically. Such a setup would be rather quiet. For the navigation, a small linux based single-board computer connected to a Kinect as the sensor.

Now using the Kinect in an outdoor setting requires use of the equipment at night to avoid the infra-red of the sun intefeering with the IR emitted by the Kinect. Thankfully the tracks and mower are relatively quiet.

The only real hard part would be the software, using the Kinect data for collision avoidance and navigation.

You would put the mower in the dock to charge, when the sun goes down, the mower comes out, does it's thing and parks back in it's dock to charge ready for the next outing.

*Terminator for when it gets hit by lightning and decides fido needs a haircut

[John 62]

dew?

surely at night there's too much dew to mow.

[Robert Heffernan]

Not necessarially

All it needs is for the sun to go down (removing the massive thermonuclear IR emitter), so it can start it's business before the dew settles in, which in my experience is in the early hours of the morning.

Obviously you could also equip it with sensors to detect such moisture, indeed a sensor would be advantageous to detect rain so it can get back to it's nice and dry dock before it really gets soaked.

[John 62]

one man went to mow, went to mow a meadow, one man and his dog went to mow a meadow...

GPS. I just read about an aussie seed drill set-up that has a 64m drill towed by two 425hp John Deere 9400Ts ("in series"). Obviously the tractors have their own GPS navigation, but so does the seed drill, which operates in a no-till system whereby the seeds are deposited in the groove _between_ the drills from the previous season. Yes, this 64m-wide seed drill must automatically steer itself so it can drill a tiny target area consistently for miles at a time. Modern agriculture is pretty awesome.

Anyway, that means that if the aussies can use use GPS for guiding a seed drill within an inch, then you should be able to get lovely stripes in any pattern you fancy on your little lawn.

[Will Wykeham]

Computer Vision

Clearly the best solution for navigation would be the some of the normal motion analysis/structure from motion computer vision techniques, for automated guidance.

Simply mount a standard vga webcam, streaming to a box in the house with a big processor. Build some software based on Open CV that is capable of identifying grass texture and distinguishing it from, say, flowerbed. It would then be track garden landmarks, flowerbeds, fences etc. to work out where it was on the lawn.

On the first haphazard pass it would build up a picture of the lawn until it had the whole lot, and after that it could calculate the most optimal route.

The software would be quite involved, but it would keep the part cost for the machine down as all, particularly if you are using an existing computer for processing resource. Processing could be put in the mower, keeping it as a fully independent, autonomous sheep/goat.

Non-obvious boundaries could be input on an interactive map, or indicated using some form of easily computer recognisable marker, e.g. QR code as someone suggested.

What I'm envisaging is a single hardware platform (designed using some of the excellent ideas above, and presumably below) on which a multitude of people are developing open source cleverness to turn it into a mower.