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Comment by cmrdporcupine | Hacker News Reader

I want to see details on power source and energy usage. That's where I'm a bit skeptical. To do the 20 acres they're talking about you'd need one hell of a huge battery, assuming it's electric. Even just to move the thing. Then add power draw for the laser on as well.

Also seems odd to have it be something that is self-powered and autonomous rather than just something you pull behind a tractor on the three point hitch (where you could power off the PTO of the tractor). Seems excessively novel, given most farmers are already spending time going up and down the rows cultivating, etc. anyways. Adds to the cost, and complexity.

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>Also seems odd to have it be something that is self-powered and autonomous rather than just something you pull behind a tractor on the three point hitch

That doesn't seem odd to me at all. The whole point of this thing is to let it run all day killing weeds while you do other stuff. The fact it only has a max of 5mph (and likely significantly slower when there are actual weeds to kill) means you would spend all day every day in the field trying to take care of weeds.

When they spray for weeds they're going significantly faster than that and cover a massive swath in one pass, and that's generally outsourced to someone other than the farmer himself. This looks like it's good for maybe 3 rows at a time.

> The whole point of this thing is to let it run all day killing weeds while you do other stuff.

There's a lot of automated tractors now

Yeah. But I wonder if putting it all in one was for better coupling between shooting laser control vs the whole cart moving around (for example, slowing down/stopping when the weed density goes up).

I noticed this thing uses hydraulic drive motors... I assume that was so they could run the engine as 'electrical first', but I also wonder if it gives them better start/stop control of the cart.

Many tractors these days are hydraulic as well.

I guess I don't follow what the advantage would be. Putting hours and wear/tear on a $250k tractor that you likely have other uses for in order to cut what? $10k off the price of this for the cummins motor and hydraulics? It would need power generation of some sort, so you'd be doing PTO off the tractor instead to drive a generator.

I'd imagine the end result would be more fuel and in the long run more expense.

The advantage with tractor-pulled is lower cost and higher reliability. The propulsion, guidance, and power-supply problem has been dealt with by industry already and is already owned by the farmer. The autonomous weeding machine will undoubtedly have issues with these three functions, which means down-time and cost. The machine would be cheaper if tractor-pulled, and the developers could focus on the problem at hand. Also, the tractor driver could periodically stop to monitor and tweak the weed killer, especially important given the new technology. We did a recent project with a farming implement that could have been autonomous, and when one is realistic with reliability and maintenance costs (unless one intends a McDonald's ice-cream machine repair business model) then the argument for tractor-pulled is very strong.

100% agree and that's what my original comment was trying to get at.

I can see selling two models, one autonomous, one three point hitch / PTO. The advantage of the latter is clear to me.

But then the product starts to look a lot less sci-fi, doesn't it? We already have pull-behind weed burners that use propane torches and not lasers. The only "magic" would be in the AI recognition systems (which I have questions about.) Perhaps one could not get investment $$ for it then :-(

Also propane torches seem more efficient to me than converting diesel combustion to electricity to heat energy.

I think the difference is that propane torches are an imprecise mechanism generally used to clear dead area between planted rows, while this laser based solution could be used selectively within a planted row (provided it is real at all).

Fully agreed about the 3-point comment though. Why take on building an autonomous tractor AND a targeted weed-killer, rather than tackling the differentiating problem only? Seems like a hype train measure. Or the systems integration is very important, in which case a partnership would be the obvious route or white-labeling an autonomous tractor. Regardless, this strategy seems very weird to me too.

Right, which is why I think it's likely a result of VC direction. It's not enough to have a profitable or sensible product, it has to be something that can sell in acquisition for 10 or 100 x the investment given.

"Autonomous vehicles are hot and AI is hot, go with that."

Yes, but autonomous vehicles with AI don't scale at zero cost like web apps, so the valuation shouldn't have the same multiplier.

>The advantage with tractor-pulled is lower cost and higher reliability.

Based on what? The cummins engine they're using is bulletproof and a rounding error in the cost of the unit. Hydraulic motors will run for 10s of thousands of hours without any maintenance beyond a fluid change.

People in this thread keep claiming tractors are fully autonomous, which model? If they aren't fully autonomous, what farmer is volunteering to spend hundreds to thousands of hours in their tractor doing nothing but putting along at 5mph stop-and-go while this thing zaps weeds?

https://www.protocol.com/john-deere-farming-ai-autonomous

My theory is JD,Case already have the tech to be level 4 autonomous but they haven't figured out how to make more revenue than selling $250K quad-tracs with 'some' autonomy.

https://thinkingagriculture.io/the-agriculture-unicorn-hidin...

Thousands... millions of farmers already putting along doing nothing but dragging a cultivator / sprayer / fertilizer spreader / bush hog / rototiller / weed badger / manure spreader etc. etc.

I assume you haven't farmed? You don't run any of those implements at 5mph with a 3-row spread. It would literally be impossible to run a modern farm at those speeds and spread.

"74-hp Cummins diesel QSF2.8"

https://carbonrobotics.com/features

There's a video on YouTube of a walk around. https://youtu.be/fK3AQgt47z4 The CEO of the company describes it as "an all diesel hydraulic system." Essentially there's a big generator to drive it around and provide power to the pew pew lasers.

https://carbonrobotics.com/features

Lasers are 150 watts, so a small fraction of the power draw.

Seems like getting the automation is key, replacing herbicides would require multiple passes over the same ground.

150W of output power.

Lasers are notoriously inefficient, CO2 ones are in the 5-20% range.

So probably at least 1000W for the lasers, assuming 10% efficiency.

The modest engine powering it is 55 kW.

People who work in pulsed kW laser labs are all sitting here salivating at thought and also horrified at the thought.

Salivating because that's a lot of power that you can use for experiments, much more than most laser technicians have ever seen.

Horrified because not only are you going to go instantly blind (as usual), but now the rest of your head will smolder too.

55kW at 240V is only 230A. A typical house gets 200A service. It’s a lot of power, but you wouldn’t have to move mountains to get it if you worked at a lab that needed it. It could be had for less than the price of many used cars.

Just a point of clarification, for a CO2 laser, getting 150 optical watts out the aperture usually means putting about 1500 electrical watts into the tube. The rest comes out as heat in the water jacket, which you pass through a radiator or possibly an active chiller, and those pumps and fans draw their own power as well.

And before those 1500W get into the tube, they go through a high-voltage power supply, which is maybe 80% efficient if you're lucky. All-up power draw on a laser of that scale is somewhere north of 2KW from the wall.

(And before anyone asks: Yes this is very good efficiency for a laser, which is one reason why CO2 is so popular. YAG and fiber lasers tend to be in the low single-digit percents.)

Maybe it's because the robot needs different amounts of time for different patches of soil? As in, it kinda needs to go its own pace to a) ensure it has enough time to detect and kill all weeds (which depends on weed density, presumably - the video shows it only killing one at a time) and b) maybe it has to stop to ensure it hits the right thing because it can't handle moving targets (not clear from the video)?

No idea if this is something that modern tractors could accommodate already or whether it would need some annoying human-in-the-loop stop and go.

Farming equipment is typically fuel based. And this appears to be the case for this robot as well: it uses Diesel.

This is in no small part because of the massive subsidization of fuel for farming in most countries. Not only is the fuel for agriculture heavily discounted, but what you do pay can be written off against your revenues.

Same with most fisheries.

If governments want these sectors to go green, that is going to be a very big and painful band-aid to peel off.

> but what you do pay can be written off against your revenue

How is that different from any other business expense in any other industry.

Operating expense is different from a capital expenditure.

You do realize that deducting the cost of producing a product is entirely normal and expected behavior right?

It’s not some special loophole.

If you use $1000 of electricity to harvest your crops, that $1000 would be equally as deductible because it’s just a cost of production?

At that point, is this more environmental than applying Round-Up to the field?

Each of these lumbering beasts goes 5 MPH, burning diesel the entire time. How many gallons of gas is going to be spent weeding a hundred acres of farmland?

Well they are quite different pollutants. Hard to compare directly.

I know, and the two are often in conflict.

For example, replacing a deforested area might sometimes be faster by introducing a non-native invasive species. From a carbon perspective it would be a net-good, from an ecosystem perspective it would be a net-bad. Which is more important?

How do you think the roundup is applied in the first place?

Diesel engines can be eventually replaced with overhead wires

In a field? Not likely.

The QSF2.8 Diesel is a Tier 4 Diesel engine, so it is MUCH cleaner burning that most tractors out there.

I don't see why power would be an issue. Why do you even assume there's a huge battery instead of a diesel engine and generator?

Having this thing be autonomous makes it more expensive to acquire, yes, but way cheaper to operate because the labor cost of pulling this thing with a non-autonomous tractor is quite large (even if the tractor were autonomous, having two autonomous robots doing different things is better than having one doing two different things that might halve its availability for each kind of task). This is a very big deal. If labor were a non-issue we'd have people weeding manually and we'd not use herbicides. Everything in farming is about labor, which is why we've gone from being agrarian societies to industrial and post-industrial ones: by bringing economies of scale to agriculture in order to greatly reduce labor costs in agriculture.

Why would you assume it was electric?

The energy usage should be minimal - it doesn't take much power to burn a leaf.

If you pull it behind a tractor, you need to hire someone to drive the tractor. This defeats the purpose of an autonomous weeding system.

> The energy usage should be minimal - it doesn't take much power to burn a leaf.

This is certainly true for dry plants. If they're weeds, they're actively growing, so they are trapping a lot of moisture that could make it hard to burn. If the weeds are a problem, then they're going to be growing. Many weeds, too, will continue to grow, even if their leaves are damaged or removed.

I think we might be using different definitions of "burn." I mean burnt by radiation so it no longer photosynthesizes -- in some plants this can happen simply from overexposure to sunlight. It's not necessary to turn it to ash.

A machine continually damaging cotyledons in emerging seedlings would go a long way. That's part of the advantage of a continually running weed killer.

Instead of a laser, I wonder if it would make sense to use positioned lenses and have the robot focus the sun's rays on each weed to burn it out. Though that probably would cause fires and would only be usable during certain hours of the day.

Why would the fire danger be different than the laser?

I could easily be wrong on this, but my understanding is that a laser is highly focused to one spot. A lens would have a wider spread and would also heat up the area surrounding the target to the point that it could ignite.

> would only be usable during certain hours of the day

Limiting usage to when the light will be strong enough to be focused would seriously limit the hours of usage

Maybe adding solar panels to harness solar energy to offset ICE emissions would be a consideration

That woukd be a good idea, though wouldn't that notably increase the cost of the unit as well?

The video looks like a mix of cgi graphics with unrelated real videos, so I guess they don't have a real machine yet.

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

(Video of an operating unit)

There is nothing particularly unbelievable about the device, and it seems, as such innovations tend to be, quite obvious.

It's driving on asphalt in a parking lot. Do they have a video of the device following the grooves over mud? (It would be not surprising, because other automated tractors can do that.)

It would be more interesting to see a video where they fire the lasers. Can it aim while moving? Can it aim while the engine is on and everything is vibrating?

"I want to see details on power source and energy usage. That's where I'm a bit skeptical."

Meh. Worse case you could even have a wire.

Hell, you could probably stick a fuel tank and a generator on it if you had to.

Which is basically what they did; upthread, someone links to the specs and they have an onboard Cummins diesel generator.

Check the Features & Specs page [1]

    74-hp Cummins diesel QSF2.8
    4 hydraulic drive motors
    75-gallon fuel capacity

I'd bet that diesel also powers a generator to run the computers and 150W lasers.

[1] https://carbonrobotics.com/features

You’d be dragging that wire over your rows of crops, potentially damaging them.

Oh it's for sure an energy hog and the 20 acres is marketing.

Super interesting especially think of it as in its infancy. Also would be interested to see how the real world results are. I'm guessing it can laser all life but I would be curious to see how well the algorithm worked with protecting certain species.

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