New video by Michael; The Factory | Simulating Microgravity with Random Positioning Machines

New video! Designing experiments for microgravity from the safety of our 9.8m/s/s has its challenges. Considering the price of rocket fuel it’s not so simple to just send your project into space on a whim, so we designed a school-friendly random positioning machine to simulate a low-gravity environment for the specimens mounted within. We were delighted to partner with the Powerhouse Museum and Claire from Unconvengineering to help make this educational workshop come to life.

Join us as we cover the process of designing, assembling, and testing our 3D-printed random positioning machines.
https://www.youtube.com/watch?v=Wz8sjB6MxHA
This video can also be viewed here

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Hi Michael, awesome video and idea. I am interested in developing my own RPM and was wondering if you could point me towards how you are able to determine the gravitational acceleration and rotation set points for the frames please? I’m hoping to be able to set a value and then continuously see what the simulated gravity on the plate should be.

Cheers!

Hi Lachlan,

Welcome to the forum! If you want to know some more info about the plate you could include a 9 DOF sensor on there to get some values. My first thought here was cable management issues but this project already solves that using slip rings.

There are a wide variety of sensors available that could work. Hopefully this provides some start point.

Great work on this interesting project.

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Heres a copy of info (found on Youtube link) https://www.youtube.com/watch?v=Wz8sjB6MxHA

Designing experiments for microgravity from the safety of our 9.8m/s/s has its challenges. Considering the price of rocket fuel it’s not so simple to just send your project into space on a whim, so we designed a school-friendly random positioning machine to simulate a low-gravity environment for the specimens mounted within. We were delighted to partner with the Powerhouse Museum and Claire from Unconvengineering to help make this educational workshop come to life. Join us as we cover the process of designing, assembling, and testing our 3D-printed random positioning machines. :wrench::hammer::toolbox:

Check out the Repo for this project here: [https://github.com/CoreElectronics/CE…]

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Hello,
I am a highschool student currently researching the developmental effects of altered gravity in drosophila larvae. For the microgravity simulation I chose this design. So far all has been going well, but upon my first couple of trials, I noticed the machine would make short movements that would soon after revert after a long pause. I understand that it’s supposed to be continuously reorienting. After going on other forums I haven’t been able to find a solution, I can only assume there’s an issue in the code. If anyone had any advice or ideas it would be greatly appreciated.
Thank you!

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Hey @June287392, welcome to the forums!

That certainly sounds like an interesting project! The machine is “continuously re-orienting”, but I don’t think the behaviour you are describing is intended.

To start, we need a few more resources, namely:

  • Photos of your setup
  • A video of the issue
  • Description/Snippets of the code

I am assuming you’ve ripped the code straight from the GitHub Repo for the project, in which case it should be the same on your end as it is on ours. However, it is still good to establish a baseline when troubleshooting.

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Thank you so much for your response but after working with it for a while I figured out I had the wrong servos. After modding them, the RPM worked perfectly.
Thank you again for your time!

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Hi @June287392

Great to hear that you got it sorted! If you run into any other issues feel free to ask away here and either one of our staff or another member of the forum will help out.

Hello!

I am trying to build this as a part of my master’s thesis. In the long term, I’d like to scale it up but for now I am trying to build this one as a prototype. The problem I have is that the servos stop working after a while (few hours), and then they will either restart when I manually turn them, or start again one time out of ten. It all worked fine at first for a few days, but now the servos won’t start when I plug the circuit.

I am trying to figure out if the problem comes from the servos or the circuit. Could it be a problem with the power source? I am using a 5V/2A USB charger.

Other than that I am using the exact same setup as shown in the video.

Thank you!

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Hey @Bob288106, welcome to the forums!

That’s a bit of a weird one if it is failing after a few hours. I have a few questions to try and narrow down the issue:

  • What Controller are you using to drive the servos? That power supply should be more than capable of driving two FS90MR Servos but it may be struggling if it is powering other devices as well.
  • In our video for this project we run into an issue with the slip ring failing. It doesn’t sound like this would have failed completely in your case but could it be possible that this is losing connection a few hours into running?
  • When the failure occurs, can you detect any power going to the servos? I would suggest breaking down this project into sections and checking each one at the time of failure to see if you can figure out where along the line of power source to servo this is not working as expected.

Hope this helps! Will keep an eye out for a response. :slight_smile:

Thanks for the quick answer!

I’m using a rasberry pi pico, like the one in the video.

I don’t think it could be the slip ring, because both servos seem to have this problem.

There is still power that goes to the servo, which is why I think they must be the problem. I was just trying to figure out if the power source could have somehow broken them. It worked fine at first…

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Can you see any visible damage to the servos?

If you are using plastic gear servos then the internal could be worn down from the constant load. If you have the servos that have the blue plastic exterior then you should be able to make out the internals.

I can’t see any, but I think it is the only option that makes sense. I juste can’t figure out why the servo broke… thanks for you help’

Hey @Bob288106,

Are you able to send some images of your prototype? I imagine it is near identical to the original, but it’s always good to have a visual when dealing with elusive issues like this.

In the video of this project, Michael mentions that he and Ahmed did a lot of “post-processing” on the 3D printed parts. Is it possible there is some hook or snag from a printer error that is causing the servos to lock up? This would be strange given that it worked no problem for multiple days, but possible nonetheless.

Looking forward to getting this fixed for you!

Hi!

Apologies for the delay in responding—I was testing a few more things. The servos work fine (for multiple days) until I put them under load with the RPM. After running for a few hours, the servos start to get hot and eventually fail. Do you think it could be because the RPM is too heavy (I’m using the same servos, so this would be surprising) or maybe the weight is not properly balanced?

I’ve attached a few pictures to help:


Thanks so much for your help!

Hi @Bob288106

We did some testing over the weekend with some similar servos and found that moving them quickly under load would cause them to heat up and fail prematurely. If you’re finding that your servos are getting hot I would recommend slowing them down in the code (highlighted in the picture below), this should help to extend their service life.