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Merci :)

nutzisch du github?

Haha thanks man =D

Thanks for watching! I am using 8.0.6 and the theme options are located in Preferences -> Preferences... -> PCB Editor -> Colors

Awesome! Just watched your NASA ASCEND video, beautiful footage. Are you going to document your next launch too?

I'm on it :) there are two videos about the schematics and one about the PCB layout on my channel right now

@@buildacubesat Thankyou, it will be a great help for Electrical engineering students.

Good point! I have done that myself multiple times. It may be beneficial to advertise the purpose of such sensors more clearly though imo.

Hey! Thank you so much for taking the time to comment in this level of detail, this is super helpful! I did understand the "unspecified signal impedance requirements" in the same way you mentioned - it's just that I don't always succeed in expressing myself coherently in these unscripted parts... I appreciate you mentioning this though. So for r2 I will definitely look into impedance control and use the approach you suggested (get in tha ballpark using online calculator and then tweak track sizes and spacings to fit in the design). That's an interesting vantage point, I have never thought of connectors being much of a problem for SI, rather cable/trace length between them and EMI. So I suppose in my design, the limiting factor may actually be the number of M.2 connectors a signal may go through in the stack up. Interesting! I dont' plan to run anything in the MHz range. For I2C, the usual 400 kHz mode will be plenty I think. You also brought up something I read a few times now, but never quite understood: Why do you think LEO would be a harsh environment regarding EMI? Would ionizing radiation (solar / cosmic background radiation) have an influence? Because thinking about just how empty it is up there, it would seem to be a much more benign environemnt regarding EMI than say an average office building. About smoothing transition between pad sizes and traces: Would you tend to step-up trace widths (like Phil Salmony tends to do) or use teardrops? Thanks again for the input. I will start a Discord next season, would be awesome to see you there :)

@@buildacubesat so to be clear this is all just anecdotal advice from my relatively limited experience as a hobbyist. my main assumption around stricter requirements in space is just, a vague sense of "radiation" being a problem, and the much higher cost of failure, since a lot of otherwise recoverable or easily fixable error states are potentially mission-ending when you can't physically access the device. i think what you're saying about it being much quieter up there is probably true, and ionizing radiation is a totally different thing from EMI, so i'm likely overstating the problem, i guess i was mainly just going off the general association between aerospace and stricter standards. I have not done any research into transitioning btwn trace sizes, my main intent was just to point out that lots of applications seem to get by with just accepting those small discontinuities. but i definitely think it's worth exploring how to optimize that, i just don't know much about that myself.

my intuition would say test your i2c bus at 400kHz, but also some much lower frequency (whatever the lowest your application can afford is) and use that in the final version, just to give you a nice big margin of safety. also: some of i2c devices implement CRC checksum functionality, you can check for that and make use of it where available to give you extra assurance

@@spambot7110 Sure, I understand that and your comments are still very much appreciated :) I want to look more into EMI/SI for space next year and ideally have a CubeSat dev as a guest on the channel who may be able to share some insights. For now, until the high altitude balloon test flight in June, I am going with a 'good enough if it works' approach to keep the momentum going, and then after that, I will start going over each subsystem with a fine-toothed comb and move into a space-worthy design direction. Well-reasoned comments like yours will be great to refer back to in the future, so thanks again for taking the time.

@@buildacubesat oh i just thought of something, when you see the length matching squiggles in a trace, when it's a differential pair of traces and the squiggle is on just one of them (for skew correction), that's another impedance deviation. so, i still don't know how to quantify it, but clearly there's a way to budget for it

Hey and thanks for the comment! I'm happy to hear that :) This is a framework 13", with the 12th gen i5. I can really recommend framework laptops, definitely check them out

That would of course be great, I'm eager to find out! =) I sent this to PCBWay for manufacturing (they also make all the CNC parts) and you're right, for flight hardware a different substrate may be needed (they also offer Rogers). But that's still a few years away :) Thanks for the comment and also the telling me about that TAH episode, will definitely check it ou!

Hey! Thanks so much for the kind words, that means a lot =) It's great to know that this stuff is useful for someone getting into the space industry. Best of luck with your studies, and I'll definitely keep the videos coming! Feel free to drop any questions or topics you'd like to see covered in future videos

Yeah basically, babushka-style xD Thanks! Yes, I placed all components in a 20 x 20 mm area, so if I didn't mess up too badly, this should work.

Hi! Great to hear that you are starting a CubeSat project - no better time than the present if you ask me :) Are you going to open-source it too? I got in touch with Richard from RGSat a while back and he mentioned being super busy with work, but not having abandoned the project. So I'm keeping my fingers crossed for him to continue at some point.

@@buildacubesat Well I'm glad he didn't quit. But yeah, I do plan on making everything open source, even the ground station. I think open sourcing things like this especially the flight computer is good for the community considering commercial products are so expensive.

@@mdarnell321 100% percent agree! Make sure to send a link to your project my way, would love to follow

Thanks man! I really appreciate you sticking with the channel through the first season 🛰

Hi Ryan, thanks for your comment! You're absolutely right - if your goal is to get to orbit asap and you have the funding, then buying a CubeSat bus with flight heritage from a well-established vendor is 100% the way to go. My project, however, is about exploring whether there can be a more accessible, open-source path for CubeSat development. So far, I haven’t hit any roadblocks, but I still have years to go before any qualification testing. So yes, commercial is definitely easier, but DIY is more interesting imho :) Did that answer your question?

Yes, I appreciate the feedback.... I was playing with this idea, as every since I was a kid, I wanted to make something of my own and have launched into orbit, standing the reason in pursuing DIY over commercial. I was not aware these had to be built by Aerospace Engineers. I was following the Stanford Model as published by NASA for the frame which i intended on building myself. As far as the payload, electronics speaking, I am looking into considering a commercia modular set-up, allowing for a customized platform.

@@ryanpuckett134 This has been a long-held dream of mine too :) Well, CubeSats certainly don't _have_ to be built by aerospace engineers, otherwise most student projects (like the Stanford one) would never have gotten off the ground. It's just that if you buy a commercial bus, it's more than likely that the people who made it are actual aerospace engineers. As far as I can tell, the only formal "qualifications" you absolutely need is a license to operate radios on your CubeSat and a company or institution to carry any insurance you may need. Apart from that, if your CubeSat passes qualification testing, you should be good. I plan to talk to Exolaunch in the near future about the details of this process and will make a video about it.

@@buildacubesat Thank you again for your feed back! I am enjoying the videos, you are definitely light-years ahead, of my progress. I like your modular rail system, I am thinking of using vertical standoffs for my application. is there a maximum width for rails, I have noticed many minimum surface requirements, but was curious if there were a maximum exterior width limit. Are you using deployment switches? If so, what switch are you thinking to use?

@@ryanpuckett134 I don't think there is a maximum rail width stated in the CDS, but usually they are as slim as possible for practical reasons, like maximizing the available volume and minimizing weight and manufacturing cost. Also, in my opinion it's advisable to not put more structural parts into orbit than necessary (to minimize orbital debris and aluminum oxide particulates in the upper atmosphere). Yes, I am planning to use a flexure to push down on dome switched on a PCB as deployment switches. There will be a few videos on that in season 2 :)

Hello and welcome! I definitely agree and I'm looking forward to what the next decade has in store in that regard :) I did reach out to Richard a year or so ago and he mentioned being busy with work but that the project had not been abandoned. Here's to hoping!

Thank you! :) I don't worry too much about radiation at this point, mainly because there are a bunch of other things that need to work before radiation can even become a problem. And also in LEO, radiation still seems to be relatively benign. My list of priorities up until the high altitude balloon test flight next year are: 1. Get it to work at all, 2. Thermals, 3. SI/EMI

It's been a challenge, but I'm trucking along :) Thanks for watching!

Hi Graham Thank you so much, I am really happy to hear that! :) Great question! I think this mainly works through providing the necessary documentation to that end. Are you familiar with the NASA CubeSat 101 document? Check out chapters 6.2 (Transmitter Survey) and 6.7 (Electrical Report). Basically you provide detailed diagrams of your system and a list of all transmitters so the launch provider can verify that your inhibit logic is sound. I think this is how it work for most missions, although I think it's plausible that a LP may conduct independent RF/EMI/EMC tests for more exotic payloads. Would that be a topic you would like to see a video about at some point? Maybe I can get someone form Exolaunch to talk to me about these things.

@buildacubesat Hi Manuel, Thanks for the reply. This would make for a great video. I have read those docs, but I have not seen anything concrete about what actual tests are done to prove it. Attestation documentation from the maker of the device is false security, it's pretty surprising that launch providers accept this. But this is part I am trying to find out about. Best Regards, Graham

Will do! 🫡

Thank you so much, this means a lot to me! :)

Thank you :) Do you mean the 5K figure? That's my guesstimation of what launch costs for a 2U may by the mid 2030s (when I plan to be ready to launch this). So no hard evidence there, just hoping for economies of scale.

Can't wait to send a CM4 (or 5?) to orbit some day! <3

Thanks for the comment, that's interesting! How would you implement this? With an ORing controller (like the LTC4358)?

@@buildacubesatinteresting ic but the voltage range of 9-24V seems like an issue. Do you have a simulation for energy harvesting part of your sat?

@@aculleon2901 Not yet, I feel like there are too many unknowns as of now to start working on simulations. Let me get back to you once I have a first draft of the schematic. Getting to that point should clear up a number of questions.

@@buildacubesat Sure 👍. I would be glad to help you. Do you have a github repo or something similar?

@@aculleon2901 Cool :) I have a Codeberg repo, but the schematic on there is very much a WIP. Unfortunately YT won't let me post URLs here, but there is a link in the description and if you go to main project, you will find the is a hardware repo.

It's called Atorch DL24, I think I got it on Aliexpress

If you still want to have a stack-up of boards, look at the proper mezzanine connectors, like Conan line from Amphenol.

Thanks for the input! This sounds interesting, do you have any visualizations of that layout? I had looked at a number of different board-to-board connectors but kept coming back to M.2 because using simple 2 layer PCBs of various lengths as connectors seems very flexible and cost-efficient. It is completely unproven though, so I may very well fall back on a different solution. I don't remember if I had evaluated the Conan line, will look into it. Thanks again!

Thanks :) Can't wait to start breadboarding.

I am going to break the PMIC and DC regulator sections out to stamp-sized PCBs that that fit on a MHP30 hot plate, hoping that this would make assembly DIY-able. I have never worked with LGA before, just BGA, but i figured the usual stencil, paste and hot plate method should work here... But yes, if all else fails, these may end up needing PCBA service then. Thanks for the heads up, that's really helpful!

@@buildacubesat - if you've done BGAs successfully this way, then the LGA should be just fine. I've stayed away from both, because I wasn't sure it'd work in a DIY environment. Good to know that it does.

Glad you liked it!

Haha thanks, that's so nice of you! It's a long way to the stratosphere, and we are just getting started :)

Thank you!

Thanks :) It sure was a lovely day for a HAB flight

Merci! =) Freut mi sehr, dases interessant fingsch!

Thank you! I was suspecting this may be the way to go.

Absolutely! You can find them here: codeberg.org/buildacubesat-project/bac-structure

@@buildacubesat god you are THE man thanks :3

Happy to help! x) make sure you're subscribed, there is a lot more to come in the future

@@buildacubesat when i saw your channel i instantly subbed x3

Thanks! Will do!