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Comment by whazor | Hacker News Reader

Hearing my dad talk in the past about machine designs to automate both tomato and strawberry machines. He recommends cutting the stalk with either a laser or a scissor. This is significantly faster than trying to pick a vulnerable fruit.

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If you do that with raspberries then you need to have people process the fruit again as they're sold without stems. Tomatoes and strawberries are sold with stems as they don't detach without cutting. Don't know what the effect would be, commercially and in terms of preservation, of selling raspberries with stems.

I think if robotically trimmed fruits with stems sold for 10% cheaper than slow picked stemless fruits, there'd be no market left for stemless by the time the season is over.

If selling with stems works fine, no doubt. But raspberries detach from stems as they mature so you may end up with a messy box after a while. Or maybe this is just done because it's easy to pick manually by grabbing the fruit and picking with stems works as well. I'll have to try picking some with stems and see what happens.

>raspberries detach from stems as they mature

If the problem can be reduced to separating objects of different characteristics from a process flow, existing food processing techniques like vibrating belts and air guns can handle it, no need for robot arms.

Ripe raspberries are very delicate. Some of these small fruits are sometimes picked directly into the final retail boxes to minimize handling. I don't know if you can apply those methods if you're not then processing the fruit further into jams or juices.

Shipping them like that would probably make it more expensive, lots of wasted space and added weight.

I think this is a much better idea, because it decomposes the problem into easier things for robots. People are talking about stems, but hold up! You can just make a second robot that picks up raspberries from a bucket and removes the stems. This sounds much easier to me.

This would only work for autumn fruiting varieties. Summer fruiting varieties fruit on 1 year old stems, so unless you identified the new stems and left them...

Yes, my thoughts exactly. I'd imagine a sharp razors and a tube that sucks air (or a net) would be much cheaper than a robot that simulates a human hand to pick tomatoes.

I wonder if someone experiment with some kind of scaffolding that would make fruits more exposed and easer to pick.

Laser might cause a fire which is why they don't use it. I think best method is to simply mimic the human hand motion. You grab the berry but you put your two fingers over the stem and then pull down on the berry until the stem disconnects. This method might be even superior to the scissors method since you won't need to replace the scissors due to dullness.

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