Crazy question about lasers for weed control

[boberino]

Hi All!

So I have a completely ridiculous question. I am a Computer Science guy with a background in image analysis. I recently read a couple of interesting articles on lasers as a potential weed control alternative. I also happen to have a small farm and hate pulling weeds more than anything in the universe and can think of no greater waste of my spare time than trying to build a pole mounted weed scorching laser turret. :evil:

Getting a microcontroller to either discriminate between weeds and not weeds (shades of color, shape, etc...) or throwing together a sort of web cam user interface to queu up targets is what I consider the easy part. The hard part for me is that I know absolutely nothing about tinkering with lasers. Also, I could easily get power to it, but was wondering if anyone ever uses solar powered batteries - such a system obviously wouldn't have to work continuously.

Does anyone have any advice on how I might learn more about how to get such a thing to work? or know of any similar systems that others have worked on?

Thanks in advance!
-Bob

 

[JBTexas]

First, I am a relative newbie to all of this. So, disclaimer, there are veterans in the forum who are better qualified for your answers, and are more creative and experienced with laser-stuff than I am.

BUT; I just HAD to reply...


First; what KIND (wavelength) of laser is going to burn vegetation the best? I am guessing: certainly not green (~532nm). I am GUESSING that you want to use an I.R. (infrared) laser, or a blue (445nm) simply because the 445s are available with so much power. Blue lasers have their own special hazard, though:
High-energy visible light - Wikipedia, the free encyclopedia
Artificial Lighting and the Blue Light Hazard
(I'd go with I.R., I think... )

I assume that your Not-Weed / Weed recognition system (LOL) will be switching the laser on and off with a fast reaction time. Just know that a laser probably can't tell the difference between Weed / Not-Weed (ROFL).

I AM qualified to discourse on solar powered energy systems. I am an amateur radio radio operator, and I've experimented quite a bit with B.E.A.M robotics / solar powered robotics.
BEAM robotics - Wikipedia, the free encyclopedia
(just to get you started)

Most B.E.A.M. hobbiests (and amatuer radio operators) use NiMH batteries ...
Nickel-metal hydride battery - Wikipedia, the free encyclopedia
... they are relatively cheap compared to Li-Ion, they can handle beefy current, and they can provide a high surge (you NEED high surge to trip a transmitter... otherwise the batteries could burn up, the transmitter will malfunction).

LATELY, I've purchased my solar panels and most of my robot parts here:
Solarbotics
(they are in Canada)
... but you can probably find higher-power solar panels elsewhere.

I did not grow up on a farm per se, but I had relatives who were on farms, and I spent some time on farms while growing up.

Just after I retired from the military I stayed with relatives on a farm while I finished up some college.

Overall I would say that your project is impractical... there are better more efficent more cost effective ways of "massacree'in weeds". BUT your idea has a high "cool" factor. Very WACKYDOODLE, in a nice sort of way.

Good luck. If/when it works, upload it to youtube.

 

[boberino]

Yes, you're right in that this is definitely more about cool points and nerd revenge than creating some sort of economically viable weed control system

Thanks for the links!!!

I'm interested to see if there's any how to's with pricing information etc.. for getting started with crazy hobbyist laser ideas like this one

 

[Jacob32123]

Welcome to the forum.

You seem to have everything but the laser covered so I would recommend HighTechDealZ - 445nm Aixiz Rkcstr Blue 440mA Laser Module for a laser. That laser will light matches pop balloons, and is a visible blue color. Goggles are required, a reflection of something could blind you instantly. That laser comes ready to be powered off a 9v battery. You could turn it on and off using a MOSFET or a relay.

Hightechdealz is run buy a LPF member, and I would recommend the site.

EDIT: The laser is small too. It is 12mm in diameter and ~30mm long. Also, that diode throws out a lot of heat so http://www.aixiz.com/store/product_info.php/cPath/28/products_id/99 should provide you with easy mounting and some heatsinking

 

[chipdouglas]

so you want to kill the weeds but not the weed. that is going to be tough the best bet is to put a plastic based mulch around your plants. this will help with 3 things... insects, water evaporation and the growth of new weeds/un wanted plants. this really is your most feasable option, although not as cool as a laser lol.

michael.

 

[hakzaw1]

BOB-- instead of pulling weeds I think you are pulling our collective chains--

using a laser to kill weeds is a hoot!

it would take less time and no $$ to just pull them by hand--

even if you charred the top of the weed it would just come back anyway''

trolling at its best-- but in a nice way

"I recently read a couple of interesting articles on lasers as a potential weed control alternative"

LINKS or it didnt happen.....

hak

 

[Tech_Junkie]

Here is a bunch of links for ya...here

 

[Jacob32123]

Here is a bunch of links for ya...here

Haha TJ that was too polite.

link

 

[Tech_Junkie]

Haha TJ that was too polite.

link

Trying to give Hak a break, but its not easy. :na:

 

[ShortyInCanada]

Boberino, you didn't mention if you were thining about keeping the laser assembly mounted stationary (in a high point overlooking a target area) or on a moving platform.(roaming the field like a roomba vacuum robot)
In a modified roomba you could mount the sensors, laser , etc. and keep the target distance set optimally while reducing the chance of stray beams. It comes with the built in software & sensors for keeping in a defined area and auto recharges when needed.
You just need to power the charger with a nice solar panel assembly.
Then it could even do it's thing at night (provided a low power light source for your detection imaging, like white LEDs, was incorporated) leaving your neighbours trying to figure out the strange blue "ground lightning" over at your house !:crackup:

 

[CapeClover]

I would also worry about the safety factor. In order to burn down weeds the laser is going to have to be very powerful, capable of burning very fast, and, obviously being used outdoors being fired at weeds near ground level there would be a potential for the beam or a randome reflection of the beam to randomly hit a the eyes of a neighbor, bystander, or the operator of the laser killer and induce blindness or serious eye damage.

Some things are better left low tech.

A better solution would be a propane weed burner or, a box of Scotts weed killer or some RoundUP :can:

 

[ShortyInCanada]

And on those crisp fall mornings the smell of burning leaves smoldering out back...
Mmmmmmmmmm.

Man I GOTTA see that one built !

 

[JBTexas]

@ shorty

I like that idea a LOT. It sounds like a combination of a couple of B.E.A.M. robot types... a "pummer" combined with a kind of hovercraft. It would "sleep" in the daytime, charging, and then activate in darkness.

He DID mention a "small farm". He didn't mention any animals... if he doesn't have any, I imagine getting 1 or 2 would be possible.

How about a couple of trained goats? Trained - or encouraged somehow - to roam the entire farm, so that all of the property is covered? The Laser Goats would have solar panels on their backs - they make them flexible now. Do a google search for "flexible solar panel". I envision ... sort of blue "goat jackets" (or red goat jackets, or orange...) ... with flexible panels covering the back of the jackets, combined with a harness and an underslung structure for the lasers, microcontroller, and sensors.

Of course, the goats need to be fitted for safety goggles. Sometimes they will drink from a watering hole or trough, or there might be the odd bit of glass or metal; the goats eyes need to be protected from reflections. And the goats should have the customary Laser Warning Labels. I suggest the goat's foreheads, or perhaps a plate mounted between their horns.

This has the advantage that 100% of the aquired energy from the sun will be devoted to the lasers, sensors, and control system. Or, for training the goats, they could be conditioned to obey small shocks from the microcontroller, until they learn how to patrol the entire property.

 

[JBTexas]

 

[Things]

If you are considering doing this, you would probably need a CO2 laser. 445nm lasers are great for close up burning, but their beam size quickly turns to crap over any distance. CO2 lasers are also a LOT more powerful, have excellent beam characteristics, and are relatively cheap.

The downside is they are somewhat large (~0.7m for a 40W tube), require water cooling, work off high voltage, the beam is completely invisible, and the tube itself is quite fragile, being glass. However, it'll burn weeds better than any diode will

As for the positioning system, you will probably want to keep the laser stationary, and reflect the beam around with a mirror system. Of course, this means you will have to program 2D space movements into your microcontroller, as well as something that distinguished weeds from normal plants.

Getting a webcam with a high enough resoultion to spot these plants over a large distance could be tricky as well, and by the time you do, your microcontroller is gonna have a had time keeping up with all that work.

 

[LORDJET]

Also, if you do decide to go the weed burning route with a laser or otherwise. Be sure you don't end up burning any poision ivy! You do not want ether yourself, or anyone else inhaling the smoke from these type plants!