# Laser lawnmower?



## hugodrax

Is this possible if I use that 445nm 1W laser, put it inside a chassis and drive the lawnmower over the grass and have the beam cut the grass to perfect length?

It would not pose anymore of a hazard than a moving blade mower and since the beam is underneath it is not visible to the eye.

Put in a safety feature such as a run only when holding on to the saftey bar just like with traditional mowers.

Is the 1W enough to cut grass as it passes the beam, a length of lets say 3-4 feet?


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## AnAppleSnail

hugodrax said:


> Is this possible if I use that 445nm 1W laser, put it inside a chassis and drive the lawnmower over the grass and have the beam cut the grass to perfect length?
> 
> It would not pose anymore of a hazard than a moving blade mower and since the beam is underneath it is not visible to the eye.
> 
> Put in a safety feature such as a run only when holding on to the saftey bar just like with traditional mowers.
> 
> Is the 1W enough to cut grass as it passes the beam, a length of lets say 3-4 feet?



Very slowly. Lasers work by applying heat to a small area, so for grass it would have to boil the water in each blade, then burn the grass blade off. Multiply the approximately 1.5mm beam diameter by the number of grass blades it must cut by the water content in a 1.5mm long section of grass - because it will have to boil that water. Once the grass is dry, it will burn the dry section off. I can't imagine this being good for your lawn.

Multiply 1 watt by the number of watts to boil a gram of water by the grams of water in each sweep of the laser and you know how slowly to sweep - it won't be fast. Lasers are not magical cutting lines. They are very bright light and they basically heat things up.


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## Larbo

Be careful when doing the dried up grass and weeds mid to late summer, could turn into a real news maker...


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## Batou00159

add multiple lasers (gellet mack 3 concept) more lasers les hassel:nana:

and you would have to add some sort of grass aggitator so that the bits that are lying down or at funny angels got caught by the lasers


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## StarHalo

Below 20% humidity, dried/dead grass becomes flammable; once you get into single-digit humidity, a spark sets off dry grass like a road flare. Pointing a 1w laser at your lawn in these conditions would certainly take care of the grass (and all the nearby structures/buildings)..


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## luceat lux vestra

That sounds great. But I have seen how fast dry grass can burn in October Not cool :shakehead


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## Linger

Aside from the cutting, a key element in the successful function of a lawn mower is the low pressure areas it creates above the blades, essential for the grass below the blades (in the comparitively high pressure areas) to stand up straight. So beyond just an aggitator, a massive blower would be needed so the patch of grass would raise up to be cut.

(un-powered push mowers to this manually with a bar that furrows the grass up and into the cutting blades.)


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## SemiMan

hugodrax ... please tell me you are not an engineer ... and if you are, civil in particular, please list all structures you have worked on so I can avoid them... ;-)

Sorry, I could not resist.... and I would like to assume this was a joke.


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## Lynx_Arc

If you could make a laser strong enough to cut a lawn as fast as a lawnmower it wouldn't be made because it would be a weapon instead and it would only take one stupid user playing tag with it to mess it up and wipe out someone's school bus full of kids with laser beams to put the company out of business with lawsuits forever. You would have to have a special deck to make sure the lasers either don't try and cut the lawnmower or reflect off it and hit someone or blind a plane in the sky also. The power needed for such a lawnmower may end up costing more in gasoline than spinning a blade and may generate more heat than a combustion engine based mower.
In other words, doesn't seem like a good idea from the start.


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## AJ_Dual

Instead how about an imaging sensor that maps out the blades of grass as the "mower" rolls over it, then a 20W IR diode is fired at a big DLP chip which then breaks up the individual beams at each of the individual blades of grass? 
:laughing:


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## Colorblinded

AJ_Dual said:


> Instead how about an imaging sensor that maps out the blades of grass as the "mower" rolls over it, then a 20W IR diode is fired at a big DLP chip which then breaks up the individual beams at each of the individual blades of grass?
> :laughing:


You joke, but I imagined something like that when I was a teen mowing our lawn. Obviously this predated the whole DLP thing and I didn't really have a mechanism down pat, but the concept and application was there in my head.

Enough dreaming about that and I guess I kept myself entertained while pushing the mower around.


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## AJ_Dual

Someday... 

But of course if you can afford all the imaging and laser direction and optics, there's no reason the mower wouldn't have Roomba-like robotic technology and drive itself too.


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## 65535

Why not a waterjet grass cutter. You'd only need a 40kW motor coupled to a high pressure pump and appropriate hose and fittings.

Water and cut your lawn at the same time. 

I guess you could probably run at slightly lower pressures, maybe a modified pressure washer, or a few ganged up.


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## IMSabbel

AJ_Dual said:


> Instead how about an imaging sensor that maps out the blades of grass as the "mower" rolls over it, then a 20W IR diode is fired at a big DLP chip which then breaks up the individual beams at each of the individual blades of grass?
> :laughing:



Do no joke, people are building such systems _right now_. Not for lawnmoving, but for pest control in agriculture. 
You take multiple cameras with image processing logic, detect unwanted plants and deliver carefully dosed laser power in the stems to kill them off.

See this paper for example: http://www.control.aau.dk/~tb/divpapers/laser_treatment.pdf


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## Steve K

that's impressive! It's still in a conceptual stage, of course. No reason to think it couldn't eventually be developed to the point where it is actually out in the fields. The idea of precision laser optics bouncing around in a field is a bit much, though...

This presents opportunities for laser hobbyists, doesn't it? Instead of using chemicals on the dandelions in the yard, they could be using their new "light saber" laser to kill the stem! Imagine what the neighbors will say. 

regards,
Steve K.


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## kingofwylietx

I tend to think that a laser lawnmower is going to be prohibitively expensive for quite a few years. I have implemented a better lawnmower contraption. I call it Jose3, as it is the third iteration. This one is much better than my previous ones, as it requires no maintenance and can be paid for on an as-needed basis. No equipment to buy & it will work while you are not home.

Seriously, while I do relish the idea of a silent mower, it's cheaper to have somebody do the work for you today......now, tomorrow, who knows.


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## wreckless1

Pop up mirrors at the sprinkler heads .maybe a fine mist to ensure no fires and zip zap ez lawn care ... now edging that's a bit tougher


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## Burgess

lovecpf
_


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## bshanahan14rulz

Step 1: remove blade from lawn mower
Step 2: replace blade with a phase converter or generator
Step 3: attach CO2 laser on vibration mounts and direct the beam to the underside of the mower
Step 4: crank up the engine
Step 5: engage generator to power CO2 tube
Step 6: hire the neighbor's kids to mow your lawn, since you no longer have a lawnmower


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## PandorasBox

I didnt think the legend of 445nm had gone this far!

A 445nm could never accomplish this task at a speed any faster than 10 feet an hour.

Other types of lasers? CO2 could as described ^^ but your looking at a very dangerous very expensive very stupid contraption.


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## Mo13

It most certainly could! It would take about 1 year per 50 square feet. Have fun!:wave:


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## enridp

Why do you think this is a joke?
There is a patent here:
http://www.google.com/patents/US6269617
And there is a real mower with laser here:
http://grounds-mag.com/news/grounds_maintenance_youve_seen_mower/


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## Remington597

PandorasBox said:


> I didnt think the legend of 445nm had gone this far!
> 
> A 445nm could never accomplish this task at a speed any faster than 10 feet an hour.
> 
> Other types of lasers? CO2 could as described ^^ but your looking at a very dangerous very expensive very stupid contraption.



I couldn't agree more! :shakehead


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## StarHalo

Eh, just creatively use whatever tools you have to groom your yard..


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## Steve K

StarHalo said:


> Eh, just creatively use whatever tools you have to groom your yard..



Isn't that the fellow that recently became known as "Stumpy"??


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## R.W.D.

This thread is a trip xD first thing to come to mind about the laser grid under your mower was the scene from the first resident evil movie where they got diced by a laser. rofl dude my dog makes so many pot holes if my mower flipped it could devastate trees neighbors my dog and who knows what else. Not to mention my neighbor likes to drink and ride his mower in the dark with shades on drunk. This could be one the the most dangerous ideas ever xD


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## mcnair55

Your idea might be nearer than you think.The next big thing in laser technology will be ignition systems on motor vehicles thus doing away with spark plugs.


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## Str8stroke

I have the Platform for this Mod, just need to buy it & ship it to Tmack! *You must click this link!* It will work! I have the Ego Blower & Hedge Trimmers! 

http://egopowerplus.com/products/mower

:naughty:

EDIT< I forgot, we are gonna have to modify the deck with some titanium mirrors!


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## LEDPunisher

1W? Nah. Now, get yourself a good 10W laser at around 290nm and we'd be getting somewhere!


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## yuandrew

There will be less of a "fresh cut grass" smell and more of a "burnt" smell.


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