Remote control electric lawn mower, video camera and A123's

[kfong]

I’m tired of paying for a lawn service, yet I hate cutting the grass. I have a corner lot which takes more time than I would rather spend and it’s not even fun. It occurred to me, that I have enough battery power with my Dewalt packs to actually cut the lawn. One of my hobbies is Radio Control planes and the other is electronics. Why not build an RC driven lawn mower that I can cut the grass with while indoors watching from my TV set in a nice air conditioned room. I can also put infrared lights and cut at night. It would be fun since I would be driving it remotely around the house. I could eventually put some intelligence on it such as a gyro to track a straight line and stop at a certain distance. Then I can manually turn it around and let it go. This is sounds like a good compromise between a robotic cutter and a manual one. From what I've been reading the robotic ones aren't that good. Has anyone heard or attempted such a design? I think I have a rough idea of the design I will build, but still researching before I begin.

[amberwolf]

You might search Instructables.com as I recall at least one such project there in the past.

I also have a corner lot that sucks to have to mow. One idea I had but have never had a Roomba to try this is a Roomba-controlled lawnmower project. Basically use a Roomba vacuum-cleaner minus it's actual motors to control the motors on a custom-made lawnmower frame. Setup the Roomba marker thingies at important points on the lawn (like to keep it from going into the street where there arent' fences to stop it, like my front yard).

(Right now the last electric mower I got as junk from someone but fixed has finally vibrated itself to death again. I have a "new" one that's probably from the 70's by B&D but I have to unsieze the pulley bearings for the twin blades... Then I have a gas mower that doesnt' have the pull-starter top part. I need to weld up a drive socket to a shaft that'll fit in a drill, so I can start it, but be able to easily and very quickly pull the drill away from the engine's starter shaft, so it doesn't yank it out of my hand and throw it across the yard or something. Gotta do it all soon, too, since some of the weeds are a foot high since the last rains!)

[hydro-one]

hmm electric lawnmowing service with robotic electric mower. could be the business im lookingfor !!!!!!

mike

[AussieJester]

hmm electric lawnmowing service with robotic electric mower. could be the business im lookingfor !!!!!!

mike

http://www.friendlyrobotics.com.au/robomow/

KiM

[Ypedal]

I wonder how it would deal with Dog shit ?

I have a good self propelled Toro pushmower, and a really crappy tractor i got for free, the tractor takes skill to operate as the belt is nearly shot to hell so pushing the clutch barely slows you down, you push the pedal and slam it into a desired gear then away you go.. the steering shaft pops out of it's knuckle so at randome times you loose steering wich is scary sometimes as it always happens when turning resulting in doing donuts in the lawn until you either manage to pop it back on while on the move or luck out where the clutch actually slows you down enough to get it sorted out.. Dead battery means using a portable 12v pack to fire it up, emergency stops by turning off the key means a walk back to the garage for the power pack..

I"m debating converting this tractor to electric and splurge on a 10$ belt ! lol.

[TylerDurden]

The complicated part is the safety: how to implement dead-man and obstacle shutdown.

[liveforphysics]

If it's going to be remote controlled, PLEASE use a spread spectrum digital transmitter/receiver setup.

I don't know how many times I've had things like RC cars, planes, heli's glitch on me from somebody else turning on an RC controller on the same frequency, or even just interference from things around me. It would be a serious hazard to have a spinning blade equiped machine getting controlled by the kid next door who decides to turn on his RC car remote. lol

Of course... speaking of danger... an RC helicopter is way more dangerous than an RC lawn mower... so maybe I'm just being a safety ninny.

RC helicopter = 1-1.5M spinning carbon fiber death moving at speeds you can't dodge by running, and able to come down and strike face/neck area rather than just foot/ankle stuff.

[John in CR]

You can pick up used wheelchair motors, gearboxes and controllers pretty cheap, then you figure out the remote control actuators. I think you'd want 2 wheels of independent propulsion for easy turning, and then another motor for the blade. I'm lazy, so I'd just get a robotic lawnmower, since they already have everything worked out.

On the other hand, I'm looking at a manual lawnmower, no motor at all, and figuring out how to make it work with a kids EV. Then at an early age (6 and 9 now) the boys can learn the joy of cutting the grass by doing it a fun way. I remember loads of fun as a kid with my grandfather's lawn tractor. An electric buggy/racecar/4wheeler with detachable grass cutting attachment seems like a good project for me. Throw in a secret means of remote control for some real fun.

John

[kfong]

Yeah, it will be a spektrum. Moved to that a couple years back and never looked back. Very reliable, only drawback is it interferes with 2.4 GHz video transmission, but I have that covered. I'll be running 400 or 900 MHz for the video. I’ve been giving this idea a lot of thought and it looks like I will be pushing it as a priority. After doing some research. I noticed most of the robotic lawnmowers were smaller than the standard size push mowers. I plan to do something in between. Initially it will be made of plywood. It should be a fairly easy build. I plan to use two motors in a differential configuration as the rear wheels and coasters for the front. This will allow the mower to turn in circles. The blades will be 2 sets at 90deg at different levels to get the clipping chopped to a smaller mulching size. I plan to use just razor blades from a utility knife. It will be easy to replace when dull. Seen this on one of the designs and it seem to make sense. Most of the cutting is at the tips of the blade. The good thing about this is it will be always sharp for cutting.

I get dog crap all the time in my yard from people walking their dogs. Nothing I can do about it but make sure I have enough power to chop it up unless it’s a big one since I don’t plan to do much cleaning . I’ll be using an RC motor to power the blades so I’m pretty sure I will have the horsepower and speeds needed. I wonder if spinning blades at 20,000 rpms is more efficient at cutting grass. I’m pretty sure lawn mowers spin at much lower rpms. I do plan to use a chain drive to gain some torque and reduce the speed. This section will use a plain RC esc.

The drive system will (2) 135watt brushed motors from allelectronics. These I already have. I will need to work out the drive electronics since it will be differential but that shouldn’t be a problem. The batteries used will be my Dewalt packs from my bike and a set of interface boards. I plan to use 3 or 4 of them. The good thing is; there will be plenty of area on top of the lawn mower for this. As far as safety, I can put a tilt switch to shut down the mower. It will have wood sidewalls so things won’t be flying around at high speeds. I plan to drive it around like a video game while indoors away from the noon day heat. It should be a lot of fun this way. I’ll put the video antenna in the attic so I will have good video coverage of the yard.

Improvements that will come in time would be a servo head tracking video camera, infrared lights for mowing in the dark and a gyro for cutting straight lines. Maybe I’ll put a speaker with voice changing properties or a horn setup for nosey kids. That should freak them out. It would be a robot to them . Eventually I can put some intelligence on boards such as going straight for a certain distance and stop. That way I don’t have to pay too much attention to the driving but still get a quality cut.

[bigmoose]

Since you mention robotics... The center of excellence at the University level is Carnegie Mellon University in Pittsburgh, PA. Their Robotics Institute headed by Red Whittaker is a leader in autonomous robotic motion as proven by their track record in DARPA's Grand Challenge. They have published many papers on the subject of obstacle avoidance and autonomous operation. They have done a couple of designs for autonomous lunar rovers...

Home web site: http://www.ri.cmu.edu/publication_sub.html?menu_id=265 might be of some help.

[kfong]

Bigmoose, unfortunately, that stuff will have to come at a later point in time. I do like robots and autonomy. One of my first boards sold on the web was based on Fred Martin’s MIT handy board, used in his robotics course. We created a smaller version of it and Doc. Martin complimented us on the design. Even put a link to help out on the traffic. I actually helped developed a vision based lane detection system to drive a car on the road at GM, but I was mostly on the hardware side. I do have some programming experience, but not at the point where I can come up with my own tracking software. Will need to copy from others to get the job done. The good thing about the net is; there is probably some posted examples out there. The difficulty is finding it. For now I’m keeping the project as simple as I can. I need to know if my design will actually cut and mulch the grass. There is no point in going on if this can’t even be solved. Once I get a good platform to run on, then I’m sure I'll keep adding improvements as long as the project remains interesting or practical.

Speaking of DARPA, I rode in the GM’s DARPA vehicle when it was at the Tech Center. It did a fairly good job navigating a parking lot with obstacles, without a driver. The GM research group I worked for actually did a good portion of the design. Interesting stuff.

Since you mention robotics... The center of excellence at the University level is Carnegie Mellon University in Pittsburgh, PA. Their Robotics Institute headed by Red Whittaker is a leader in autonomous robotic motion as proven by their track record in DARPA's Grand Challenge. They have published many papers on the subject of obstacle avoidance and autonomous operation. They have done a couple of designs for autonomous lunar rovers...

Home web site: http://www.ri.cmu.edu/publication_sub.html?menu_id=265 might be of some help.

[bigmoose]

kfong, you prove again that Endless Sphere is populated with the most talented and experienced people in the business! Makes one want to stop posting. We were involved with Red a bit a few years back. My past employer provided Red with a Radioisotope Stirling Power Simulator for one of his lunar rover platforms, of which parts were machined in my basement to make schedule...

[kfong]

Bigmoose, you give me too much credit. I’m mostly a hands on type of guy. Theories and real engineering eludes me most of the time, but I do like to learn. Especially, if it’s fun or interesting, then covering such topics has relevance and I’m not drifting away thinking of my next kiteboarding session.

Sounds like you have a fun workshop as well. I practically live in mine during the winter months if I’m not outside snow kiting or on a ski trip. Lately I've been fascinated in working with composites and epoxies. Nasty stuff though but has lots of structural potential for ebikes and the various projects I’m always doing.

kfong, you prove again that Endless Sphere is populated with the most talented and experienced people in the business! Makes one want to stop posting. We were involved with Red a bit a few years back. My past employer provided Red with a Radioisotope Stirling Power Simulator for one of his lunar rover platforms, of which parts were machined in my basement to make schedule...

[Doctorbass]

Hey.. Great idea... since i'll move to a new house ( the one that i bought recently .. and not rent like i do since 4 years..)
i'll need a great lawn mower.. and.. i've been also thinking about a Remote control electric lawn mower !... with konion or A123.. and maybe one of my Bionx 500W motor that i'll convert into delta mode for higher KV for spining the blade...

The very first BionX brushless electric 48V lawn mower !!!... no pedal!...

The BionX motor is very thinny so i could have alot of room for placing battery on top of it.. using the motor heat loss to keep the cell at their best internal resistance for MORE POWER i'll also use the original Bionx controller since it is not really big and direct insid ethe motor.. but i'll replace the IRF1407 130A 75VDC 7mohm RDS on by some 4110 or 4310

or.. i might minally use the delta wye for two speed and torque depending on if i cut the grass every week or every two week( need torque)

Doc

[bigmoose]

I was hiding behind the bushes a bit ago while Methy was testing his new prototype for a mower. It was clearly a Version1 awaiting the arrival of more LiPo because of the cord...

Rt click and save as, then play please:

http://www.mtg-technologies.com/video/ElectricMower.wmv

[John in CR]

Thanks BigMoose, what a way to end the week. I don't think I've laughed that hard yet this year, since it caught me just right.

John

[kfong]

LOL, I hope mine is that powerful, then I can race through the yard and have time trials It will sure make cutting the grass something to look forward to

[AussieJester]

Thanks BigMoose, what a way to end the week. I don't think I've laughed that hard yet this year, since it caught me just right.

John

BWAHAHAHA same he even looked a lil like Methy...i gotta stop reading ES when im having breakfast, makes
a mess of my keyboard...

KiM

[dumbass]

I like this one. It looks like someting I would have built when I was a teenager trying to get out of cutting the grass. http://video.google.com/videoplay?docid ... 853601428#

[John in CR]

Thanks BigMoose, what a way to end the week. I don't think I've laughed that hard yet this year, since it caught me just right.

John

BWAHAHAHA same he even looked a lil like Methy...i gotta stop reading ES when im having breakfast, makes
a mess of my keyboard...

KiM

BigMoose giving it to us just made me that much more off guard. I was busy trying to figure out if it was Methods, since it didn't quite look like him. Had I been eating or drinking anything I would have made a big mess of my keyboard and monitor too.

John

[jag]

I'd be excited to hear about your progress. Some observations:

If you have a differential drive with two separate motors the mower might not go straight for very long before veering unless you design some stability into the system. Front wheel (differential) drive and a third RC controlled steering wheel in the back might do it. (so you can seer with the rear wheel on straights, yet still turn on a penny).

An alternative that is more suited to as rectangular yard, than I presume your L-shaped corner lot would be a wire gantry. There is a way of making a two motor, constant length wire drive mechanism XY table (this was patented about 100 years ago). I forgot the details, but one of the robotics profs here is generalizing it to 3DOF so I could find out.

[kfong]

Not too concerned since an RC gyro would be easy to add. That should help it track.

I'd be excited to hear about your progress. Some observations:

If you have a differential drive with two separate motors the mower might not go straight for very long before veering unless you design some stability into the system. Front wheel (differential) drive and a third RC controlled steering wheel in the back might do it. (so you can seer with the rear wheel on straights, yet still turn on a penny).

An alternative that is more suited to as rectangular yard, than I presume your L-shaped corner lot would be a wire gantry. There is a way of making a two motor, constant length wire drive mechanism XY table (this was patented about 100 years ago). I forgot the details, but one of the robotics profs here is generalizing it to 3DOF so I could find out.

[kfong]

Here is a rough outline of what I’m planning to build. It will have a 20” cutting blade. The Dewalt packs are 36volts, the motors are 135watts each. I’m thinking 3 Dewalts is all I need, but as you can see I can easily put more. The front wheels will be just coasters; it’s somewhat similar to the big commercial grass cutters. I’m pretty sure they just use coasters in the front to get good maneuverability. It’s actually a very simple design, so it should be an easy build. I will probably use aluminum sections where the wheels mount for durability. I will probably will glass the plywood in the final design. The chains used will be #25, most of the parts can be obtained through http://www.allelectronics.com.

[kfong]

I like the grass edge detection idea, that would somewhat automate the process. I could try using a sonar sensor. Put it low enough to see the grass edge, it would be like a robot mouse following a maze. Then all I have to do is cut a perimeter and let the mower finish the rest.

I like this one. It looks like someting I would have built when I was a teenager trying to get out of cutting the grass. http://video.google.com/videoplay?docid ... 853601428#

[kfong]

Working out the details, decided to add another dewalt pack since there was room. Was planning to have the drive chain for the blades to be exposed to the grass clippings but this might get clogged or require more maintenance. Instead, I’ll just make up a chain cover for it and have it on the top. I wonder if I should make it front wheel drive instead of rear wheel, I suppose I should just try it an see which way has better traction. The only thing that would change is the direction of the motors, but I would still have to plan my sensors for the changes and the video camera location.