Blow the seed with vaccum pump


We experience that seeds are not released from the needle when the vacuum pump stops. Is there a way to make the pump blow on command?

@jensGeorgsen I’ve hit this before when seeding. In my case, the seeds are not actually stuck but rather they just need a bit of extra time to allow the pressure to drain from the vacuum line. The problem is solvable by adding a WAIT block after the command that turns the vacuum off. Once the line pressure drops to normal, the seed will fall.

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Hi @RickCarlino, thanks for the tip. This might be a solution. But it would increase speed and reliability to blow. Do I understand correctly that the hardware does not allow this or is this more a software limitation?


I do my planting on an older v1.2 device, so I will defer to @Gabriel for verifying this statement with regards to 1.5 harrdware.

My understanding is that “no” you cannot reverse polarity from the software due to hardware reasons.

Yup I use a wait block. Also it is better to seed in dry soil otherwise water can cause the seed to stick and pump to fail. The v1.5 added a filter to help with this problem.

Hi @whitecaps, I am using a different way to seed. The reason is that I would often lose the seed from the needle when it hits the ground. So I would end having a dirty needle and the seed on top of the soil.

What I currently do is watering the soil, poking holes where I want to seed and then release the seed above the hole. This seems to work okay. I just try to improve. Waiting is a possibility but blowing would be better. Let’s see what @Gabriel says concerning the hardware capabilities.

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That sounds like a good work around @jensGeorgsen.

I was going to test this for automated harvesting but have you considered a pneumatic jamming gripper for the seeding?

Thanks for the idea! That’s really cool. I imagine, that for harvesting, this might work better then for seeding. I would think that it would grab a lot of seeds at the same time while still having the issue that the seeds are not released. This effect might even be worse with the rubber surface. What do you think?

The type of vacuum pump included in kits does not switch flow direction with motor polarity.

There are a few forum topics related to the ability to switch pump flow direction, including this one and this one.

Actually there may be a mechanical solution for this particular use case. You might be able to trigger a valve to switch between the inlet and outlet of the pump. The trigger would be pressed by contact with the ground. Of course you would want a spring return once the pump stopped.

I was imagining a very small bladder for the seeding side of things. It would allow the seeds to be of any shape though.

Here we go: