Building A Homebrew Robotic Lawnmower? 486
mmonkey writes "With the seemingly small amount of summer we get here in the UK, the last thing I want to be doing on a sunny day is mow the lawn. So I started thinking "surely a light-ish lawnmower could 'gain' a couple of motors, and suddenly be computer-controlled?". Then I started thinking about stuff like obstacle avoidance, optimum path planning, guidance system, how to get pretty-looking stripes, and I realised that it's actually a potentially complex (read: fun) thing to do. So, have any Slashdotters done this before? Did you modify an existing lawnmower or build a whole new one from scratch? What motors work best? For that matter, what type of mower works best? I know you can already get these, but that detracts from both my geek-drive and my wallet, both of which I'd prefer to keep as full as possible."
MIL (Score:3, Informative)
Re:Just for you? (Score:2, Informative)
Features:
Fully automated Docking Station mower
Recharges it's power pack by itself
Departs on your schedule
Manual controller (can be used as like a traditional mower for trimming small areas)
It seems expensive, but it if you really want it (and want it now) they are availiable. Even if you don't wan't to spend that type of cash and want to build it from scratch, I'd recommend visiting company websites that develop these and download their product brochures. You might be able to learn enough from them to get some tips on getting started. Look for white papers, FAQs, product manuals too...
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9 Gmail invitations availiable [retailretreat.com]
Search the library (Score:5, Informative)
Back before everyone had the internet Popular Electronics (or one such magazine) had a couple articles on this. Lookup it up in the library, you did get the skills of searching in school, didn't you? They operated on batteries, but you could do whatever so long as your managed to power your computer.
The idea was a bunch of sensors, made up of LED senders and receivers. Mow a path around the yard, plus around any trees, and then turn the mower on. It should attempt to keep 2 sensors out of grass, and the rest (~20) in the grass.
BTW, mini-itx boards now have 12 volt power inputs, so things should be easier in many respects.
Re:How About.... (Score:2, Informative)
Oh come on. Where the hell is he going to get sheep in England?
Joking aside the parent post need not have been joking. You can actually hire lawn care people who use sheep and goats to trim lawns. They're very effective and can be used even in the rain. They're highly water resistent, as anyone who has ever worn a proper British fisherman's sweater can attest to. Different species of grazers actually eat grass to different hights as well, so you even get that choice and they automatically fertilize as they, ummmmmm, go. They can also be used for things other than trimming lawns, but I won't go into that here.
I fully understand the article poster's geeky itch to build a robot mower, but sheep are probably actually a more effective solution given his enviromental conditions.
KFG
Re:Uhhhh (Score:5, Informative)
You have that kind of backwards (and wrong). The Asimovian rules are:
1. A robot must never harm a human being
2. A robot must follow a human being's orders, unless that conflicts with Rule #1
3. A robot must preserve itself, unless that conflicts with either Rule #2 or Rule #1.
Re:Keep it Simple (Score:3, Informative)
Autonomous Lawn Mower Competition (Score:5, Informative)
Re:Uhhhh (Score:3, Informative)
1. A robot must never harm a human being, or through inaction allow a human being to come to harm.
The second part of that law might seem unimportant but it is just as important as the first.
Without the rest of the first law a robot could cause a human to die by 'accident'
been there, done that (Score:2, Informative)
Robomow [composters.com]
One already exists (Score:4, Informative)
robocut (Score:4, Informative)
robocut [robotshop.se]
Might be an interesting kit.
Robotic Mowers Not Far Off (Score:1, Informative)
If you live in the southeast Michigan area, are interested, and possess several of the skills below, please contact me.
* fluent in C/C++
* embedded programming skills
* relational database experience
* controls theory, including optimal control, adaptive control, and state estimation
* CAN networking
* brushless motor control
* navigation and path planning
Regards
Bill
Re:How About.... (Score:2, Informative)
Tell that to my goats! I have a Pygmy/Dwarf Nigerian cross goat and an Angora. The Angora will always run at and complain bitterly to anyone who enters his pasture. A stranger will almost surely be butted by the Angora. The pygmy will also charge sometimes, just not as much.
Fl (Score:5, Informative)
Hardware Ideas (Score:5, Informative)
http://www.tri-m.com/products/engineering/index
I would use the MZ104 CPU Board. They have a Linux distro you can throw on a DiskOnChip pop that in along with a regular old 64mb laptop SODIMM and you are good to go.
You can use the IR104 i/o board to provide 20 digital inputs and 20 digital outputs. This should allow you to hook up some simple sensors as well as giving you control capability. You may also need some sort of Analog I/O board, but I would avoid this for cost reasons.
The MZ104 CPU Board also has an I2C Bus interface with linux driver support. There are a plethera of different sensors available that you can directly read from this simple two wire bus.
These products are extremely affordable, rugged, low power and small. The entire system can run off of 5VDC. You can even lower the clock rate to save power.
If you do decide to go along with this, please add a wifi card and a web cam so we can watch it mow in real-time.... (uhhh oh slashdotted lawn mower)
You could obviously do this with something that had a lot less horse power, like an 8051, HC11 or Z80, but you would have to make up a lot of custom circuitry to get the job done. I like the modular nature of the PC/104 form factor. If you do opt for something with less power, I would definately make sure it has a built-in i2c controller.
Re:Uhhhh (Score:2, Informative)
Re:Uhhhh (Score:2, Informative)
"It seemed to him that there should be a still more general rule than any of the Three Laws. He called it the Zeroth Law, since zero comes before one. It is:"
"'Zero. A robot may not injure humanity or, through inaction, allow humanity to come to harm.'"
"'Then the First Law must read:'"
"'One. A robot may not ingure a human being or, through inaction, allow a human being to come to harm, except where that would conflict with the Zeroth Law.'"
"And the other laws must be similarly modified..."
from Predlude to Foundation by Issac Asimov (heh in case you couldn't guess)
Edge sensor (Score:2, Informative)
The commercially available robot lawnmowers use this. Lay the wire around the perimeter of your lawn and around obstacles like flowerbeds. It takes the guesswork out of edge detection.
talk to these guys first (Score:2, Informative)
Re:Simple solution with no electronics involved (Score:5, Informative)
Take a self propelled motor. Attach a stiff rod to one side of the deck so that it extends past the front about 2-3 feet. Tie a rope to the rear of the mower and then to the front of this rod with some slack in the middle.
Experimentally determine a good spot along that rope to attach another rope such that when you are holding it the mower tends to turn slightly towards you. Attach that rope to the (now staked) 6x6 post in the middle of the yard. Start mower, defeat the dead man's switch (usually a bar you have to hold to keep the mower going) and let it go.
Tricky problem (left as an exercise for the reader): The rope tends to self wind up past the top of the post. Especially when mowing large tracts of land.
And yes, the neighbor kids did make fun of me at school. Saved me from mowing an extra acre though, so I didn't much care what they said.
-Adam
Just buy a Robomow www.robomow.com (Score:1, Informative)
They've also released a home vacumn cleaner, which is next up on my must purchase list. .
BattleBots (Score:2, Informative)
Building your mower from scratch would be something fun and geeky and not *too* difficult if you know how to weld and such. If you take this route, consider using battery power for the drive train and a small engine for the blade. I recommend electric power because it is easier to interface with a navigation computer and allows for easy reverse if you get stuck up against an obstacle. You could even use another electric motor for the blade. In any case, a good source of electric motors is NPC Robotics [npcrobotics.com]. They also have wheels you could use. I think a remote control system would be neat, even if you don't want to drive it around all the time. You could use it to guide the mower if it's "lost" or as an emergency shutoff from inside the house. A manual override feature would be cool to just drive it around for fun, too. Of course, this makes things expensive. But a neat way to do this would be to use an IFI Robotics [ifirobotics.com] Isaac 16 [ifirobotics.com]. This system includes a radio and transmitter plus a BASIC Stamp computer that is easily programmable and allows the reading of 4 analog inputs and 8 digital inputs (sensors on the mower). This would allow you to have, for example, an "RC startup" button inside your house that would remotely trigger the mower to begin running, then use the programming features for automated mowing. It could be both RC and autonomous, really. With that system, you could use a couple of Victor 883 [ifirobotics.com] speed controllers to regulate your drive motors. There's also a spin controller [ifirobotics.com] that would be perfect for your blade if that were electric powered. Otherwise, a simple gas engine with a servo on the carburetor throttle would suffice for control of that.
If you don't choose to go with this (very expensive but neat) RC setup, you could use a much simpler BASIC Stamp [parallax.com]. This is the "brain" of the Isaac 16, but minus the radio and PWM signal drivers (for speed controllers, servos, etc.). They run a lot cheaper ($150 for a basic setup) and are still very easy to program (a modified BASIC syntax) but you would have to wire your own interfaces to speed controllers. This can be done, but I have no experience with it. In any case, the BASIC Stamp would allow you to connect various types of sensors that you could use to gather data and then modify your path accordingly. The Stamp is probably a better choice than a Mini-ITX or similar because it is cheap, not overkill
So check some of that out. I hope that helps if you're looking to build something from scratch.
Oh yeah, if you're concerned about powering an electrical system for long enough to mow your lawn, a few 12 volt lead-acid batteries of the type used in motorcycles or smaller car ones will likely suffice. I believe they can deliver around 14 Amp-hours or so.
Comment removed (Score:3, Informative)
Husqvarna (Score:2, Informative)
Re:Lego Mindstorms? (Score:3, Informative)
Even better... (Score:3, Informative)
Bring on the minisheep [mlode.com]!
Re:Uhhhh (Score:4, Informative)
They make two types, an auto mower which has a 4 Ah battery and goes back to a recharging base when the batter is low and a solar mower which has a solar panel on top and doesn't need a recharging base.
From the website the automower can handle a maximum area of 1500m^2 and the solar mower 1200m^2 with the solar mower working during sunlight hours and the automower working 24 hours a day.
The boundary of where each cuts is marked by an electric loop and both have sensors to find their way around objects.