Post by thread:robot lawnmowers

no not funny, i don't think that any of us (with lawns) haven't thought of this project. i see they have a link to the 2x compass. i read the specs and didn't feel that this device was accurate enough for a guidance system. counting ticks on the wheel revolutions won't work either because the ground is not flat. i saw a robot show on tv where they used dual gps receivers about the size of a pack of cigeretts. does anyone know who makes devices like this. or how would you send a robot 200 feet (70 meters) down a property line without mowing over your neighbors flower garden? michael

Michael S. Hagberg wrote: > > no not funny, > > i don't think that any of us (with lawns) haven't thought of this project. i > see they have a link to the 2x compass. i read the specs and didn't feel > that this device was accurate enough for a guidance system. counting ticks > on the wheel revolutions won't work either because the ground is not flat. i > saw a robot show on tv where they used dual gps receivers about the size of > a pack of cigeretts. does anyone know who makes devices like this. or how > would you send a robot 200 feet (70 meters) down a property line without > mowing over your neighbors flower garden? Any GPS receiver with differential input capability will do. One remains stationary and calculates the range errors. These are sent to the roaming GPS receiver which applies it to its own position. It's gonna be one expensive lawn mower... -- Friendly Regards Tjaart van der Walt spam_OUTtjaartTakeThisOuTwasp.co.za _____________________________________________________________ | WASP International http://www.wasp.co.za/~tjaart/index.html | | R&D Engineer : GSM peripheral services development | | Vehicle tracking | Telemetry systems | GSM data transfer | | Voice : +27-(0)11-622-8686 | Fax : +27-(0)11-622-8973 | | WGS-84 : 26010.52'S 28006.19'E | |_____________________________________________________________|

At 07:14 AM 11/18/97 +0100, you wrote: >Michael S. Hagberg wrote: >> >> no not funny, >> >> i don't think that any of us (with lawns) haven't thought of this project. i >> see they have a link to the 2x compass. i read the specs and didn't feel >> that this device was accurate enough for a guidance system. counting ticks >> on the wheel revolutions won't work either because the ground is not flat. i {Quote hidden}>> saw a robot show on tv where they used dual gps receivers about the size of >> a pack of cigeretts. does anyone know who makes devices like this. or how >> would you send a robot 200 feet (70 meters) down a property line without >> mowing over your neighbors flower garden? >> >> michael > >the gps is not too reliable at this resolution :) >the vector is good, but you have to measure the distance from a few >points to make a reliable navigation system >(or you could detect the position of the 'mower with some kind of ccd >and send the directions back thru radio) > How about a metal wire buried a few inches below ground at the edges of your property? You could have the wire conduct an oscillating current (maybe 60Hz). The landmower would then detect the resulting EM field using a simple high gain amplifier, which would tell the landmower that it is at the edge of the property. Or perhaps even better, bury the wire in the path of the lawnmover so that the mower simply follows the buried wire around the yard, avoiding trees, etc. Dave Hackos Dept. of Physiology University of California, San Francisco

In message <.....34711B95.77023832KILLspam@spam@facstaff.wisc.edu>, Dave Mullenix <djmullenKILLspamFACSTAFF.WISC.EDU> writes >Someone recently asked (possibly humorously) for information on PIC >controlled robot lawnmowers. Well, I don't know about the PIC, but here's a >page devoted to robotic lawnmowers: > >http://www.idx.com.au/~deverett/mowbot/archive.htm > >It also has links to other robot lawnmower pages. Start designing now. >Spring is only four months away. > >Dave, N9LTD A former colleague of mine was working on one. It used a 16C84 and basically did a random walk around his living room floor within an area delimited by a cable carring a very low-power RF signal. He never actually got it cutting grass, they had their first child and he didn't have the time to spare to finish it off. Before he built it, he did a graphical simulation of the random walk algorithm on the SPARC he used at work. Leon -- Leon Heller: .....leonKILLspam.....lfheller.demon.co.uk http://www.lfheller.demon.co.uk Amateur Radio Callsign G1HSM Tel: +44 (0) 118 947 1424 See http://www.lfheller.demon.co.uk/rcm.htm for details of a low-cost reconfigurable computing module using the XC6216 FPGA

>> i don't think that any of us (with lawns) haven't thought of this project. i >> see they have a link to the 2x compass. i read the specs and didn't feel >> that this device was accurate enough for a guidance system. counting ticks >> on the wheel revolutions won't work either because the ground is not flat. i >> saw a robot show on tv where they used dual gps receivers about the size of >> a pack of cigeretts. does anyone know who makes devices like this. or how >> would you send a robot 200 feet (70 meters) down a property line without >> mowing over your neighbors flower garden? Surely this is an ideal project for ultrasonic ranging: Four ping-ing transponders (well, three, but four for reliability) at the corners of your lawn triggered by low-power radio from the mower-mounted controller will give you accurate distances, hence position. You need to walk the mower (or just the controller) around the area to be mowed, logging coordinates as you go, and then let it fill in the bit in the middle. The ultra-sonics will probably keep the moles away. too. <G>. I know this kind of technique has been used on automatic follow-spot systems for stage use. It had a PC as the 'smarts' but a PIC might do. Incidentally, on the subject of splitting this list: I believe if you try and separate out the threads into newbie stuff, advanced stuff, OT stuff etc. you'll kill the reasons the list works well. I'm just as interested to hear about ideas/problems/solutions in the electronics you find around a PIC as in the PIC itself. Yes, it does take a while to trawl through all the messages - but the advantage of having such an active list is that if you post a query you can bet on a replies within 12 hours. I think the occasional rambling thread (Canadian accents comes to mind?!) is a small price to pay. Alec =========================================================================== ________ / ______/ W5 Ltd. ______ ______ _ / /___ \ \ / \ / /____ \ 33 Sneath Avenue \ \ / \ / __ / / London NW11 9AJ \ \ / \ / / /_/ / United Kingdom \ \/ /\ \/ \_____/ \ / \ / Telephone +44 181 922 7778 \ / \ / Fax +44 976 650 110 \______/ \_______/ eMail EraseMEmailspam_OUTTakeThisOuTW5.co.uk Technology * Innovation * Design * Solutions

Several years ago there was a series of articles in Radio-Electronics (I think?!?!?) which was a do-it-yourself autonomous lawn mower. It used a series of split IR emitter/detector pairs to sense the "length" of the grass blades. The steering mechanism attempted to keep half of the IR pairs in the uncut grass. Using this method, you mow around all of the obsticles in the yard, then go to auto mode and let the mower do it's thing. I'm not sure what it did when it got done... Regards, Jack Warren

part 0 581 bytes I think this lawnmower is sold by Husqvarna in Sweden and costs about 1500 USD. I don't know if it has a theft protection system, but it would be easy to implement a code lock. I am currently interested in robot vacuumcleaners. The same stategy can't be used there, since indoor areas are smaller and more complex. A vacuumcleaner that navigates at random, can't be trusted to clean all areas. But there are reliable and cheap solutions to that to (they are NOT radio or ultrasonic navigation, GPS or expensive computer vision). However, the brain is not a PIC. Glenn Sweden

Hi Guys, The only comerical robotic lawn mower I know required you to bury a cable which is really the only truly safe way to handle the problem. There is still the issue of what happens if the cable fails due to a power outage. Ben ---------- From: Charles Hoss[SMTP:timothyspam_OUTBEKES.HUNGARY.NET] Reply To: pic microcontroller discussion list Sent: Tuesday, November 18, 1997 1:14 AM To: @spam@PICLISTKILLspamMITVMA.MIT.EDU Subject: Re: Robot Lawnmowers Michael S. Hagberg wrote: {Quote hidden}> > no not funny, > > i don't think that any of us (with lawns) haven't thought of this project. i > see they have a link to the 2x compass. i read the specs and didn't feel > that this device was accurate enough for a guidance system. counting ticks > on the wheel revolutions won't work either because the ground is not flat. i > saw a robot show on tv where they used dual gps receivers about the size of > a pack of cigeretts. does anyone know who makes devices like this. or how > would you send a robot 200 feet (70 meters) down a property line without > mowing over your neighbors flower garden? > > michael the gps is not too reliable at this resolution :) the vector is good, but you have to measure the distance from a few points to make a reliable navigation system (or you could detect the position of the 'mower with some kind of ccd and send the directions back thru radio) bye charley

> saw a robot show on tv where they used dual gps receivers about the > size of a pack of cigeretts. does anyone know who makes devices like > this. or how GPS like this is only accurate enough to tell you that your lawnmower is within several dozen feet of your lawn. If you have a *really* big lawn, this may be useful. Also, GPS gets intentionally `fuzzed' in times of war and other international tensions, so you risk mowing your neighbors lawn instead. (Which, of course, might be a kindness if he or she is a called-up reservist or something.) -tom --------------------------------------------------------------------- KILLspamtomssKILLspamids.net - 401-861-2831 - 42 Forge Road, Potowomut, RI 02818 USA

Consider a Goat Benifits 1. Self propelled 2. Enviromently friendly 3. Will destroy grass to the extent of its tether. 4. Provides libral quantites of fertiliser and distributed in a random manner. 5. Quieter than conventional mower. Non benifits 1. Prone to destroying other crops. 2. Requires water as a propellent. 3. Need stake to tether it to. 4. Needs to be kept away from washing see 1 above. 5. Requires small shelter from adverse weather but so does mower. Well its an idea maybe sombody could elabrate on the above ideas. Cheers Steve.

At 02:24 PM 11/18/97 +0100, Glenn from Sweden wrote: >It wouldn't work and it wouldn't be cheap. With the existing level of technology, the perfect robot lawnmower already exists. It's a lightweight solar powered thing that doesn't actually navigate but just rumbles around in the garden at random. It turns another way if it hits an obstacle (and most gardens ARE full of unpredictable obstacles - garden hoses, soccer balls, garden furniture, buckets, barbecues etc). A radio-wave emitting cable can be buried to prevent it from entering plantation areas and get stuck in plants. The lawnmower is a bit slow since it is so tiny, but on the other hand it is silent and can be always working! Since it's solar powered it never needs to be recharged or refilled with gasoline. > >I think this lawnmower is sold by Husqvarna in Sweden and costs about 1500 USD. Closer to $5000 US. I don't know if it has a theft protection system, but it would be easy to implement a code lock. There is. The buried cable transmits a code word. This lawnmower is reviewed on the web page I posted yesterday. I saw one in operation a few years ago at a solar power fair. It's a neat device. I'd have one of they cost $200 US. Dave, N9LTD P.S. It's silent, except that it beeps regularly while operating. It also has other beep patterns it uses when it gets stuck, etc. Also, you have to mow a narrow strip around the outside edge of your yard that the mower blades can't reach and also in any shady areas, which the mower is programmed to avoid. Personally, I'd like to get one just to see how my cats react to a large green "mouse" bumbling around their territory, going "Beep beep!".

A friend of mine has one of the Husky solar mowers...He reckons they trample more grass than they cut. You might need the mower to 'hover' if it is going to be effective. Also the price is a bit too high, about 3000 UK pounds or so. Kieran ---------- From: Dave Mullenix[SMTP:RemoveMEdjmullenTakeThisOuTFACSTAFF.WISC.EDU] Sent: 18 November 1997 22:30 To: spamBeGonePICLISTspamBeGoneMITVMA.MIT.EDU Subject: Re: Robot Lawnmowers P.S. It's silent, except that it beeps regularly while operating. It also has other beep patterns it uses when it gets stuck, etc. Also, you have to mow a narrow strip around the outside edge of your yard that the mower blades can't reach and also in any shady areas, which the mower is programmed to avoid. Personally, I'd like to get one just to see how my cats react to a large green "mouse" bumbling around their territory, going "Beep beep!".

On Tue, 18 Nov 1997, Michael S. Hagberg wrote: > a pack of cigeretts. does anyone know who makes devices like this. or how > would you send a robot 200 feet (70 meters) down a property line without > mowing over your neighbors flower garden? Well, it seems to me that the boundary problem is the one where accurate position measurement is the most important. However, there is a system, designed to restrain dogs, called "invisible fence" -- it consists of a cable buried around the area you want to restrain the dog to and a thing that goes on the dog's collar. When the dog crosses the buried wire, the device gives the dog a shock. I would think that this could be easily adapted to the problem of mowing the neighbor's flowers. Pierce Nichols "I have a work order for the immediate demolition of your reality tunnel." -Bob, RAW Construction Corp. --Begin Geek Code Block--|------Begin Goth Code Block------ v3.12 |v3.1 GAT[GCS,GS] d-@ s+: !a |GoCS2)$PS3$ TJtAn PGL B10Bk! c++@>$ u+>+++>$ P+>+ |CDbrp8S V6s M4 ZGoPuExgExtClMe L+>++ E+>+ W+ N++ !o K+ |C7ome a20 n5F b56 h180 g6T??95F/A W-- O- M- V-- PS+ PE+ Y+ |m1Ea@Z3? w6TA V3 r6EP p54565Rd PGP t+@ 5+ X++ R+[GURPS] |D37 h6 sM9P SsYy k6Z N??91OE [DARKSUN] !tv b++>+ D I+ |RfsS Lus9 !D G++ e>+++++ h r% y++ |-------End Goth Code Block------- ---End Geek Code Block---| ------------Begin Magick Code Block, v0.92------------ M[WITCH] S* W+ N+ P[CE][GR][OT]++ Dr a- C++ G !Q 666 Y ---------------End Magick Code Block------------------

> > thing that goes on the dog's collar. When the dog crosses the buried > > wire, the device gives the dog a shock. I would think that this could be > > easily adapted to the problem of mowing the neighbor's flowers. > > > > Pierce Nichols > > > > Yeah, but the flowers would die if you shock them... > Silly, you don't shock the flowers, you shock the Lawnmower. Roger (The only place I want to see another #$&^ goat is fixed as part of a dish at an ethnic restaraunt. They are more destructive than a teething puppy, and a billy goat has to be one of the vilest creatures alive.)

Checked your website. Pretty neat, David: MOWING ALGORITHMS: You are using a random series of 10' x 10' mowed squares. One of the people whose sites I looked at yesterday ran mathematical simulations of purely randow mowers. He figured that his random mower would cover his entire yard in 24 hours of sun. I'm looking to do a very simple mowing algorithm. Why? Less software. Fits in a PIC1654. [Be still, ye flamers - it IS on topic!] I'm going to use a simple bumper object avoidance system, and if the mower hits an object, it stops mowing (in case it's a dog or a kid) turns a little, and begins going in reverse. I don't know if turning the same amount each time, same direction, or a pseudorandom amount each time is better. I may run some simulations myself. Think of that screen saver that draws a relatively random shape on your screen. Does it not cover the entire screen eventually? For a simple shaped yard, this may be enough. For a complex yard, it may not work. So I have to pick the thing up and place it in another section every once in a while, maybe? Still beats mowing by hand. POWER BUDGET: I'm trying to go real small. I was out in the yard last night trying to mow with a 30MA cassette motor and a piece of trimmer string. It wimped out pretty bad. I'm going to go through my junkpile and find the wimpiest motor that will actually cut grass, maybe go with a more efficient cutting mechanism. (Stainless steel wire has been suggested - I like the idea. Might not cut off a foot stuck under the mower, just beat it up some) Why? The power budget sets the size of everything else - the solar cells, the chassis, the frame, the cloud-and-shadow batteries, etc. Besides, I'm just starting out. That's one of the basic questions. I'm looking at 1 or 2 square feet of solar cell, and maybe a 5:1 or 6:1 charge-to-mow ratio. Where do you buy your cells and how much did they cost? {Original Message removed}

Lawrence Lile wrote: -clipped- Why? The power budget sets the size of everything else - the solar cells, the chassis, the frame, the cloud-and-shadow batteries, etc. Besides, I'm just starting out. That's one of the basic questions. I'm looking at 1 or 2 square feet of solar cell, and maybe a 5:1 or 6:1 charge-to-mow ratio. Where do you buy your cells and how much did they cost? I choose to go with 10'x10' patterns to give some uniformity to the cutting. I visited a couple of web sites mentioned yesterday dealing with "Mowbot". Some one there had done a simulation that showed with a 6:1 (I think) ration that he could cut his yard in a week using random motion. I have no doubt of this, but having a random cut in the middle of a section that was cut 5-6 days earlier probably would not look to good to the neighbors. :-) As I see it - which does not make it right - the only additional hardware needed is separate PWM outputs for the drive motors and some sort of feed back on wheel rotation to measure distance traveled and the velocity of each wheel. Dual PWMs is why I choose the 17C44. While I have not yet tried any cutters, my plan to an Al disk with a pair of utility blades was tried and found to be successful by one of the writers on Mowbot. My current flow chart has the LG doing the following when it runs into an obstacle: 1) stop the cutters, 2)backup a short distance, 3) turn cw 90 degrees, 4) change the length of that side of the square to account for the shorten distance traveled, 5) activate cutters and start forward motion. I have tried to be very current conscious with my design. The drive motors and cutting motors are just over the current capacity of the solar cell panels. By having a pair of on board 12v gel-cells, I hope to be able to run most all day of any sunny day. The solar cells were purchased from Jameco - sorry I do not have a catalog with me at work. The spec's, as I remember : 12"x12" at 4 watts, price ~$50. I am using two of these units. Hope this helps, David V. Fansler Network Administrator AutoCyte, Inc. 800-426-2176 Ext. 261 TakeThisOuTdfanslerEraseMEspam_OUTautocyte.com <RemoveMEdfanslerTakeThisOuTautocyte.com> Now Showing! http://www.mindspring.com/~dfansler <http://www.mindspring.com/~dfansler> Last Updated On March 29,1999 Opinions Expressed Within Are Mine And May Not Reflect Those Of My Employer