Hacker News Reader

Comment by motohagiography | Hacker News Reader

Given where ML and CV are today, I'd bet on open source models trained on weeds within 3-5 years. This company can scale, but their unit price is going to plummet. Also, it sounds like they're using cameras, where it's concievable that other future sensors could be more efficient. An iteration of this with higher resolution cameras and small flying drones seems like an intuitive next step.

This is a super interesting problem because the confusion matrix (fp/fn/tp/tn) rate that makes this economical is going to be variable across both crops, and market demand.

If there suddenly there was a demand jump for peas, you could afford to use a model with less accuracy, because you are optimizing betwee a sunk labor cost and margin on your yield. You could literally tune your detection parameters based on futures price data, since if if prices were high, you could optimize compute on your model. Anyway, spoken as a total outsider, but what a cool and interesting set of problems.

View on HN

Drones do not seem like a logical step for me. I'm not a laser expert, but seems like the energy storage needed to kill hundreds to thousands of something with light is heavier than flying would realistically allow. Wheels and tracks are what farming is built around, no need to literally reinvent the wheel here.

To me that message implied weed recognition and marking with drones followed by destruction with the cube.

That's my understanding too but what about precision?

Both the drone and the ground robot would need milimiter precision geolocation to coordinate otherwise the laser can miss the weed.

No they don't. They need fairly coarse tracking (A few feet or so.) for geolocation as that is only to make sure you end up covering the whole field.

Now for individual weeds you need precise aiming but that's only from a few feet away at max.

The overall geo location boils down to being able to track a row as you go down it and then go to the next row at the other end. The lasers don't care about the geo location at all.

RTK GPS has +/- 3cm Lat/long precision. That gets you very close, and then with a confirming camera, you could aim and fire.

Unless you have a precise map of all the weed locations, precise location in absolute world coordinates doesn't seem too important. You'd need fairly precise and accurate relative positioning from tank to drone and drone to weed, though. Drone to weed could be done via camera (you need to detect the weed anyway), but tank to drone would likely be a difficult engineering problem.

A flying drone seems like the wrong way to solve the problem, though. For a drone close enough to the ground to reliably detect weeds, you'd likely need a multi-rotor, a slow flying fixed wing aircraft, or a blimp. A multirotor has a huge energy penalty, and a fixed wing aircraft or blimp loses the practical gains vs. just using a tractor of some sort.

Ah, the classic "Death Cube and Tracker Drone" design pattern. DCTD for short.

Good point, but you havent thought of the *millions of tiny mirrors* they'd obviously be using :)

They'd probably just use rare-earth magnets.

One mirror mounted on the drone would be enough. And a strong enough laser device at a stationary position. Of course, the challenge would be to hit the mirror and not the drone ...

What about putting them on an electrified wire? String a grid of them over the fields for motion and for power. Power the grid with solar.

It stands to reason that if you're going to be running wires over the entire field you wouldn't need flying drones so much as you would need cameras on wheels (like they have at football stadiums).

If the camera sees the correct spectra for a known weed it can drop down and get a closer inspection then mark the spot or just burn the weeds with an attached laser.

I assume the crawler is necessary because--in order for the laser to work--the weeds need to be identified very early as they emerge from the ground. You might not be able to spot them at such an early stage from above without expensive optics.

Yes totally agree on the benefits of early detection — easier to identify eg. once the desired crop is larger than, say 10mm, then just fire the laser on anything green that is less than 2mm, adjust those parameters as required as the crop matures, also getting them early means less laser energy required to kill it, longer battery life, larger acreage covered

Wire is too expensive for that. You need thick wire to hold itself up without posts every few meters, which in turn means it is more expensive than the normal house wires. Not that it couldn't be done, but it is too expensive.

Now there is opportunity to have one long wire that the tractor reels in/out as it makes passes. This isn't a flying drone, but that isn't really needed for anything other than cool.

No, wire gantry would be very much ok for this solution.

You don't need wires to be that rigid for that.

Any kind of wired setup would interfere with other tractors they use in the field. Fertilization, and eventually harvesting.

I’m not sure why people are inventing more complicated solutions when this robot seems to handle the job quite well without them. It covers 20 acres in a day, you can likely keep 100+ acres weed free continuously without any other special gimmicks.

I think most people here don't run large farms, and actually want something for their garden.

I would see the drones being used to help map weed concentration and optimize the route/efficiency of the weed killing robot, not using drones to kill the weeds.

There are already solutions that use drone photogrammetry to map crop health, ground coverage and so on. It feels like a logical next step to use a drone to assist mapping the best route/find problem areas to target for the weed-roomba.

>I would see the drones being used to help map weed concentration and optimize the route/efficiency of the weed killing robot, not using drones to kill the weeds.

That's a ridiculous solution to a non-existent problem. The robot literally has no rush to go to the weeds. It can crawl along the field by itself 24/7. Throw in a solar panel charging station and you literally have free energy for it to piss away.

Instead you want to add complexity to the setup, increase maintenance costs and potentially shorten the lifespan of the system.

Ok thank you. Common sense on non-programming topics on HN is more rare than I would like. You clearly understand the problem better than most

That does depend on how much area it can cover per day.

If it covers all your land in under a day, sure. If not, then route planning may mean you can have one rather than two or more of these very expensive machines.

It's not a drasticly complex addition, and mapping weeds with drones appears to be a use of them already.

> That does depend on how much area it can cover per day.

This assumes weeding is a time sensitive task, which I find very doubtful. Realistically covering your land area in a week is probably enough, but maybe that's much higher.

It’s not ridiculous at all, hours count. I haven’t looked at the article, but I’m assuming it’s the same machine, it’s a 10,000 pound unit with tiny little tires and a 75 hp diesel engine. It’s going to compact the soil, get stuck, and waste fuel driving around looking for weeds.

If sending a 20 pound gas drone with a 2 TB solid-state drive and 60 FPS 4K camera on it up and down the field for one 100th of the fuel consumption once a week saves 500 hours a year off that beast, it’d probably be worth it.

> It’s going to compact the soil, get stuck, and waste fuel driving around looking for weeds.

This true of any modern farming equipment, which is why planting strategy is so critical--I kept messing up in my first year as I was going way too fast instead of taking my time and my planted rows were never straight, it was in a green house and we had an old diesel tractor so my lungs were hurting after the first hour and I just compromised on that aspect.

But then when I had to go back and weed, maintain and eventually harvest the oddly planted fields of salads and potatoes I made sure to follow the natural ebb and flow of the soil compaction, which was there even after it was tilled.

What I'm saying is that the compacted soil can help you in later seasons to maintain the direction of growth so it's not entirely a bad thing to have. And unless you farmed the same fields for several seasons/years you would overlook this as a net benefit. Eventually seasoned farm hands can do it while drinking and smoking and just listening to how the engine is struggling without even touching the steering wheel, they can even get out of the tractor and walk ahead of it as it's crawling forward to check if everything is fine. Where as for apprentices like myself who had no real experience in Ag it was a remarkable discovery that one shouldn't overlook.

Also, drones are already widely in use; they monitor temperature and moisture in real time and a offer other services right now [0]. Their is a company that I found that posted here on YC a few years ago that offers this as a service [1].

I was actually going to get my commercial drone's license a couple month's before I retired as a farm manager in Hawaii due to extensive injuries, but my fintech startup required saving and scraping all my pennies to afford getting it off the ground. I might consider getting it again as things start to be more widely deployed and the costs keep coming down and I still would like to be involved in some capacity in Ag.

0:https://uavcoach.com/agricultural-drones/

1:https://www.crunchbase.com/organization/terravion

agricultural drones run on gasoline and have plenty of energy

gasoline? I'm thinking ethanol derived from fermentation of the parts of the plant that were not shipped to market.

yeah could be that as well, definitely some conventional ICE engines, not batteries

Drones also have poor flight time to recharging time ratio. Which means you need more of them to get the job done.

Farms are designed to be serviced by farm vehicles. A vehicle makes a lot of sense.

If they were able to make drones work, it could open up more variable farm designs: rows are mostly necessary so that farms can be serviced by vehicles.

Polyculture farming could become much more economically feasible if drones could weed out all non-whitelisted species.

Would also be a great boon to forestry: would be awesome to make a bunch of drones to fly through forests and zap any non-native invasive species it sees.

>If they were able to make drones work, it could open up more variable farm designs: rows are mostly necessary so that farms can be serviced by vehicles.

Sure, but the weedkiller isn't the only vehicle that needs to work on the farm. I don't think flying drones are going to be ploughing any time soon.

> zap any non-native invasive species it sees

Given the climate change it could be the other way around. Zap some native saplings, which can no longer thrive.

> If they were able to make drones work

Yes, let's put powerful lasers on drones flown by AI. What could happen? I just hope the human recognition model doesn't shoot more of one race than another.

Drones don't need to be battery operated - but, I agree that there is no reason to use them in fields which are already designed for vehicle access with semi-standardized dimensions.

If they're fuel powered drones, they need to refuel. Plus that's potentially expensive to operate depending how many you need and how heavy they are.

There's probably something to be said for hard-wired drones here. The weight of the cable is something you have to contend with, but with a physical wire you can run a larger drone longer.

How is that better than a wheeled drone dragging a giant orange extension cord behind it?

I'm not sure that's a great idea either, but flying brings more problems than it solves in this problem space.

Given that the plants are on the ground, I imagine not sweeping over them with an extension cable would be an obvious advantage. Still, you could work with suspended powerlines as easily for the big-box drone as with tractors, which brings me to another (probably dumb) question: Why has nobody built a landline electric tractor?

Farmers sweep things along the field all the time. The standard farming sprinkler is supplied by pipes / hoses which are bridged above crop height between wheeled towers. As the spinkler works its way in a circle on the field around the water supply, the towers roll over a negligible amount of crop.

> landline electric tractor

Well, there are some robots that travel on aerial lines, typically used for cable inspection. Here's a quick search result: https://spectrum.ieee.org/automaton/robotics/industrial-robo...

For vehicles, crops yes, animal husbandry often roads get you to parts of a property but are far from covering a property.

Helium assisted drones could provide longer air time.

Hydrogen. Even lighter, much cheaper, and would save on a (very!) finite natural resource.

And, hey, with unmanned drones over rural fields you won't get any Hindenburg disasters.

I'll bet there's creative solutions that could take advantage of a hub and spoke model. Picture a solar recharging base station that drones can dock with to charge while others rotate in.

DJI has some demonstration of target pesticide spreading drone https://www.youtube.com/watch?v=mfdWYztSqUI It's not as targeted as laser, and it has residual problem, and requires the crop to have resistance, or the pesticide/weedkiller to be specifically targeted.

But I think it might be possible to focus sunlight to generate energy to kill weeds, not through battery or generated electricity.

Drones will be a big player in next 2-10 years (search for Rantizo). The more they can operate autonomously the better. The small payload size on drones aren't a huge problem if you can have 'refilling stations'

Maybe very small drones with mirrors and cameras and a ground-based robotic tank with a laser cannon.

This is an incredibly great idea.

I love the image of this in my head, but I can imagine in practice that many farms are not on flat terrain where there's direct line of sight [fire] for a central station to flash a lazer pulse. Perhaps if you had many smaller stations with these laser cannons spread about the field and each cannon would coordinate with the drone in the closest line of sight.

Pretty sure they're explicitly suggesting indirect fire, actually. Base station fires at mirror, and drone uses mirror to reflect laser to target. There might be stability problems, angle-at-which-it-hits-the-weed problems, and more-laser-scattering-due-to-longer-beam-path problems, but line of sight itself should be fine since the drone is up in the air.

Indeed a good idea, but I would only hope it would have a reliable fail-safe, becaue it would be a little reverse GoldenEye.

Or it could just fly upside down. maybe add wheels to set cutting height :)

The scene from Spies Like Us always comes to mind when bouncing lasers around. Or the Real Genius as well. So you better be careful using this around corn fields, or we know what can happen.

Heat-ray welding Tripods.

Spoken like a true software engineer.

Tethered drones might work.

Completely agree about flying: but I wonder about the wheel.

A spider-carriage walking robot which could step around the valuable plants, climb steeper hills, and wouldn't dictate a row-and-plow approach to agriculture, that could be pretty compelling. Less soil compaction, more flexibility, could work inside forested regions as well. It has potential.

Still easier to harvest if you have the rows though.

IMO; I think setting up lightweight aluminum rails, and run a framework of multi-purpose bots along that. Since the technology is getting lighter and lighter, it seems you could even do this and use LESS material than these gargantuan tractor/harvester/combine units. It may not even be necessary to plough fields anymore, when a smaller automated unit could just operate on the least amount of soil necessary for the plant to thrive.

Also: no more chemical weed killers.

Do this with bugs, and get rid of insecticides as well.

It's not just the robot though, it's the millions or tens of millions of dollars of wheeled or tracked equipment he already has.

When they can scale this down for home use, I think the market will want legs. A miniature Imperial Walker ambling around your garden zapping weeds would sell.

I don't think you really need AI/CV if you have multispectral or full-spectrum imaging. Different species will have different absorption/emission at multiple wavelength. This makes it easy to identify crops, and seems to be commonly used for aerial imaging[1-3].

That kind of sensor is expensive though, and while you could probably do it for cheap with something like a DLP wheel (edit: or an array of different light emitters) plus a B/W camera, ML might be more price-effective, though probably more error-prone, so it isn't a given if you want a high match rate.

Also, isn't this a fire hazard?

[1] https://en.wikipedia.org/wiki/Hyperspectral_imaging#Agricult...

[2] https://en.wikipedia.org/wiki/Multispectral_image

[3] https://en.wikipedia.org/wiki/Full-spectrum_photography

> This makes it easy to identify crops

...until they evolve to emit the same spectrum of light as the crops being harvested! Cuz you know that's going to happen.

Bacteria and viruses do that, but weeds first don't reproduce as fast and second humans can see them and find out something like treating crop seeds with fluorescent color.

That’s a slow process, further you can always rotate between crops with different spectra.

It sounds like a slow process but plant life cycles are yearly compared to 20+ years for human generations to spawn, it will happen faster than you think. There are already round up resistant weeds and it's only been 50 years.

Even 30 years after first implementation would be several generations of better hardware and software. Spectra is just one way to get v1 out the door, there are many ways you can improve things.

Crops are planted in a specific pattern, at a specific time, grow at a specific rate, and have a unique shape. So you have a lot of information to work with.

Well, that's right, and I didn't think of it. But besides what the sibling comments pointed out, that's an issue with any kind of weeding, including manual.

The answer is to select according to a wide range of criteria, and not rely on a single one. That way, weeds cannot progressively acquire resistance, and need to check all the boxes at once, which makes it highly unlikely that they will pass on their "slightly better" genes.

And of course, the larger the scale you employ a single weeding system at, the more risky it gets. It would be great for supplementing herbicide (while lowering doses) at first, for instance.

This is the part where Monsanto starts engineering crops to fluoresce in a particular frequency of light, so you can target weeds inversely.

That makes me think that this also makes crop-rotation obsolete. You can plant 20 different crops in the same field, in repeating sequence. The bot will take care of them as-needed, and next season, move everything down one slot.

Eventually, the only organisms that remain will be mutualistic ones, if we do it right.

This is a known process already https://en.wikipedia.org/wiki/Vavilovian_mimicry

Examples of this are Rye and Oats.

We just need the weedbots to test plants for flavour and nutritional value; cf. xkcd.com/810

> you have multispectral or full-spectrum imaging

...that's exactly what CV needs to handle.

Well, right, but it doesn't need particularly impressive algotithms to achieve something with that data. Those algorithms were here 20 years ago, with less processing power and camera resolution.

A lot of modern ML is not that impressive either.

I can imagine discriminating species of a hundred leaves in a very high resolution images to be very challenging.

The leaves are 3-dimensional objects can be twisted, tangled, curled up, broken, half rotten, sunburnt...

I think the AI solution is actually pretty well proven. I use PlantNet to identify weeds in my yard and it's plenty accurate and doesn't require any sort of advanced sensor.

Could be, but having more discriminating data as an input can only improve speed and accuracy. I don't know what technology they picked for the first iteration, but can only imagine they'll end up using every trick in the book going forward.

A slightly more advanced sensor or lighting apparatus wouldn't cost much more, proportionately to the cost of the whole system.

The cost would be acquiring a training data set that includes data from the more advanced sensor, versus existing catalogs with many millions of images and tens of thousands of species.

> Also, isn't this a fire hazard?

Unlikely. Heating a plant to kill it is considerably lower power than heating a plant to combust it and turn it to ash. It would also be trivial to add a water sprayer as part of the process.

Actually, the next most logical version is an implement that runs off the PTO drive of a tractor, not drones. One needs to piggyback off existing infrastructure, not replace it.

My high school summer job actually was helping with wheat harvest. You can only work when it's hot as you get better prices on the harvest.

There were certain kinds of weeds that really clog the combine (usually ragweed, not a huge problem in the early summer, but weird things happen) or cause damage to the cutting head (invasive brush/tree species). We walked the field and pulled anything really bad out.

Talk about a way to earn $25/day. You only finished when the equipment was put up for the night.

It doesn’t need to recognize every possible weed species, just “crop of interest / not crop of interest”. A much simpler but still valuable task.

A real world useful variant of Not Hotdog. https://news.ycombinator.com/item?id=14636228

That was my first thought as well.

My second thought was, "Please nobody invent a drone that shoots lasers at 'not hotdog'".

Hot dog, no hot dog?

I wonder why it can't it be done via location? Where we planted, vs where we did not plant.

This is the comment I came here for.

I had a professor in college who was building self-driving tractors and would come in every other week complaining about John Deere this, or Case that, trying to steal his business with more expensive solutions. It turns out you can use GPS for a rough location and a fancy $200 gyroscope for millimeter precision. Then just plant the seeds on an exact grid and you know that anything not on the grid is a weed.

And actually, his suggestion was to use high-pressure water jets to cut the weeds instead of lasers. It would/could be less energy-intensive.

RTK GPS is used as a second factor to vision in these machines. It’s just not good enough to target with as a sole / primary factor in the real world though. Bit of drift and whoops, $30,000 of crop gone.

Lasers are not used because they’re expensive and dangerous. And Co2 lasers (as per the machine in the article) are powerful but super fragile.

Water shooting around at high pressure is in no way efficient or easy to handle.

Compressed light is the technology that’s actually going to be used for precision weeding. It has the speed, power and simplicity of lasers, without the cost and danger: https://www.linkedin.com/feed/update/activity:67899797724715...

Thanks for posting this, very interesting. The linkedin profile pointed to a youtube video (unlisted) that was pretty interesting and covered how they could calculate eye safely using simple math that indicated the safe distance was 2 meters away. They appeared to be using blue LEDs at high intensity to char-or-inactivate weed photosynthesis.

https://www.youtube.com/watch?v=CnL3zYhBlVs

Its like cabling or rails have never been used before to guide a machine along its intended path. Alternatively, markers could be placed at planting.

it'll probably end up being something like a gamma ray source; as probably the cheapest and most durable solution.

That's what made sense for my company; we just identify the crop, and then churn up all the areas of dirt that are "not crop". Also, hey, free cultivation. Do it often enough, and your weeds never even get that large, which also greatly increases your identification accuracy.

My prediction, this thing will be built into pivots.

Most farms irrigate with a giant automated system that sweeps around the field in regular intervals. These weed death lasers could be integrated to the base of the system and ran from the same power that moves the pivot.

Since these things don't move all that fast, you could have a central track and move the killer box up and down the line.

yes, this seems like a natural progression.

It wouldn’t even have to burn all the weeds on the first pass. It’s like the herbicidal equivalent of mark-and-sweep garbage collection.

> Also, it sounds like they're using cameras, where it's concievable that other future sensors could be more efficient.

Bit of a pedantic note:

What other sensor could you use?

I'm grasping at straws (pun not intended) to figure out any other modality that could work as well in a giant field of psuedo-randomly mixed plants with the wind blowing chemical signatures all about.

I think the question was just visible light cameras vs other wavelengths.

With visible light, all you have to go on is small differences in shades of green and shape of the leaves. With other spectra you'd have more cues.

Perhaps he just meant IR sensors? Also, I wonder whether UV sensors would be helpful.

I assume they mean "visible spectrum" when they say cameras, because that's what most off-the-shelf systems are tuned to.

A spectrometer is a single pixel camera, I guess, but it isn't being used with imaging optics, and it isn't being used to stitch together a photograph.

In a general case you could embed some version of GFP instead of glyphosate resistance. Then you can set the system loose (within the field, lol) to actively interrogate plants, zapping intruders that fail their scans.

Don't think there will be a need to bio-tag weed versus no weed. Current tech and sensors can probably get to 2-3 9s worth of accuracy (bonus, you don't care about accidently hitting/killing a false positive or two, there are many plants if this is a commodity crop)

I wonder if Monsanto seeds will start producing a signature that could be recognized. This will help in 2 ways. First, more easily identify those pesky farmers using their seeds without proper licensing. Second, help the machines know what plants to keep, and the ones to remove.

Monsanto.....doesn't exist anymore....Laughable people hate on Monsanto/Bayer for protecting their IP, but when big tech does it it's just good business

But if you add a bio-tag, you can make your system look like ED-209 and recreate this scene: https://www.youtube.com/watch?v=iYUnp-x0SDE

i'm sure i'm oversimplifying but if you can reliably identify your crop then everything else is a weed. Maybe put some kind of GMO marker that makes what you want to keep stick out like a sore thumb then you just nuke everything else.

If you know where your crops are, everything else is a weed.

This is the traditional approach and it really blows my mind that so many hammer-syndrome AI/ML/flavor-of-the-month VC spenders haven't simply gone to see for themselves what works on farms. It probably doesn't even register to the casual observer, but planting a careful row of tomatoes with the root ball in a particular direction is a fit for the cultivator tool to come by and turn the soil up on the stem of the young, but now established plant.

That's actually the "weed control at scale" developed in conjunction with the tractor.

I'm not a fan of modern conventional agriculture. The abuse done to topsoil is terrible, and we need better systems. But new systems need to keep their eye on the ball and the ball is a John Deere pulling a 40-foot cultivator across a field while the "operator" reads twitter ( or <verb>s Clubhouse ) only looking up to mind the turns.

Everything starts somewhere, but just because your tech has ML and Laserbeams doesn't mean it passes the tool/toy test.

I wonder at what point it becomes economically feasible to breed crops that are more distinguishable from weeds?

After all, this is what we did with chemical weedkillers.

I wondered about the corollary - at what point does selective pressure create a weed that's indistinguishable from a crop?

I doubt weeds will be able to maintain advantages that let them compete well to begin with, while also evolving to evade all of a series of detection techniques that will be added as they evolve their way around the first few. To stick around they need to survive well outside of fields, too, and I'd expect detection-resistant varieties to become increasingly inefficient at surviving in areas where they're not being lasered to death.

well, same, do we have weeds that have evolved resistance to roundup?

Commodity drown with high powered laser for killing things based on image recognition sounds like sci-fi dystopia.

All roads lead to Skynet, some less obvious than others.

Yeah, I imagine massive overuse on "pest" species. Mosquito eradication will be a high priority for such technology, but there will be people who modify it to eradicate everything that flies or crawls. Everything smaller than a cat, if they could.

I think lasers for killing large animals (including us) will be prohibitively expensive for a long time to come, fingers crossed.

Don't worry. The robots can use machine guns like the rest of us.

Bill Gates was already involved in a startup to radar identify and kill mosquitos with lasers . . . guess it did not go well.

It resulted in a prototype that apparently cost $50 per unit, but no retail product yet.

https://en.wikipedia.org/wiki/Mosquito_laser

Are there massive amounts of retail products in, say, Africa?

Yes, Africa's retail market was worth US$1.4tn in 2015.[1]

1. https://www.brookings.edu/wp-content/uploads/2018/12/africas...

Unfortunately, you don't need that much power to permanently blind a human.

for that matter; microwaves cook us from the inside out at 100+ meters, and don't require very good aim.

Just don't step on the field and you won't be mistaken for a rat and be zapped.

True, but it seems less dystopian than soaking vast fields with millions of pounds of neurotoxins, like we do today.

I know a lot of farmers that would respond very well to having "laser weed killer" as a product. I get the feeling the video feed would be amazing. Throw in pest killing and you own the market.

Although I keep thinking the movie Runaway (1984) is going to be a much truer representation of reality than I would like.

I'm not sure that "killer robots with lasers that can be field-trained to identify specific targets" would be quite the blessing that everyone seems to think.

Why do your weeds have 2 eyes, a nose, and a mouth in all of the training libraries?

>An iteration of this with higher resolution cameras and small flying drones seems like an intuitive next step.

The gimbal alone on your flying drone will cost more than the entire river.

Non-engineer speculation. Seems like drones might have the potential to make it cheaper? What if the laser was tower mounted and the drones just were there as a camera and reflector and to verify clear line of sight? I guess that would only really work well when the plants are small...

My first thought was that ML-guided flying drones with laser weapons seems like it could be catastrophic is hacked. Imagine someone changed the drones to recognize humans (or, assuming the lasers can't hurt a human normally, the eyes of automobile drivers) as valid targets.

Open Source models don't need to be trained on weeds. They need to be trained on whatever product is being grown. Everything else can be zapped regardless of what kind of weed it is.

Sounds a lot safer to whitelist what can be zapped rather then blacklist what can't, no? I mean, this is a moving autonomous laser platform we're talking about.

Microwave powered drones. Have a mothership or tower track and send energy to the drones.

I'd like a lawnmower sized one for my yard!

Reply on news.ycombinator.com