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{ "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/G6RVR67XIMLUOHSCXL3ICDWXMTYP43QS/?format=api", "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/?format=api", "message_id": "[email protected]", "message_id_hash": "G6RVR67XIMLUOHSCXL3ICDWXMTYP43QS", "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/RQX4DLDIYY3MVVVNFRFO357N5UXLTUIQ/?format=api", "sender": { "address": "w5did (a) amsat.org", "mailman_id": "8da25cae70294f3687f590ebe6fded03", "emails": "https://mailman.amsat.org/hyperkitty/api/sender/8da25cae70294f3687f590ebe6fded03/emails/?format=api" }, "sender_name": "Louis McFadin", "subject": "[eagle] Re: CAN-Do-Too! ??????????", "date": "2007-07-10T03:32:45Z", "parent": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/67GB3DVX35OY2RFF2TT6GQAONRPIJWWI/?format=api", "children": [ "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/TTAXE4IAMYG3DK62OKWNABJJAHU5UYFR/?format=api" ], "votes": { "likes": 0, "dislikes": 0, "status": "neutral" }, "content": "I agree with all your comments Chuck. I would add one additional and \nthat is make some provisions for mounting the widget other than the \nconnector.\n\nLou McFadin\nW5DID\[email protected]\n\n\nOn Jul 9, 2007, at 10:56 AM, Chuck Green wrote:\n\n> Hi Guys,\n>\n> Juan has done a lot of outstanding work which resulted in some\n> substantial critiquing of the CAN-Do! (Affectionately called a\n> \"widget.\") It is unfortunate that it has taken several years since \n> the\n> CAN-Do! was designed and then 100 units built before an application of\n> sufficient sensitivity used it to discover it's shortcomings. History\n> can provide lessons that I hope we can learn from, but it seldom\n> provides solutions to the problems encountered. Lyle and I have\n> exchanged a few thoughts privately and it seems it may now be time to\n> consider solutions to the problems found.\n>\n> The only practical way to accomplish this is to develop the next\n> generation CAN interface device. Dare I call it the CAN-Do-Too! ?\n>\n> All technical specifications should remain the same. What this really\n> means is that a next-generation controller must run *exactly* the same\n> firmware currently running the CAN-Do! .\n>\n> All specifications added or redefined should be carefully defined \n> and be\n> measurable.\n>\n> General specifications that we worked from before were that the widget\n> should use as little power as possible and consume as little of a\n> module's volume as possible. The first of these should remain the \n> same,\n> \"use as little power as possible.\"\n>\n> But the second should be changed to \"consume as little of the \n> connector\n> panel space as possible\" even if it means consuming a little more \n> of the\n> module volume. This means the widget PCB and components should not\n> extend beyond the dimensions of the DA-15P connector in either\n> dimension. A possible compromise to this would be to let the PCB run\n> past one end of the DA-15P but not more than the DA-15P is forced away\n> from the side of the box by the box design.\n>\n> The power supply could be completely redesigned. Or the inductor \n> of the\n> existing supply could be exchanged for one that is a toroid (the\n> existing one is not). If someone wants to step up and design a new\n> power supply, great! If not, then we would simply change the \n> inductor.\n> I'd sure like to see someone take this on. With so many of these \n> in the\n> satellite, only a few milliwatts is important. And the noise issue \n> Juan\n> uncovered is *very* important.\n>\n> It may be that some, or maybe all, of the widget should be enclosed \n> in a\n> metal box. It may be that just changing the inductor would allow a \n> new\n> widget to meet the yet-to-be-defined noise specifications.\n>\n> The input power filter for module power should be separate from the\n> widget power supply input filter. The module power filter is a filter\n> that will not meet all module requirements, but would likely meet the\n> requirements of a digital module. Some modules, such as receivers, \n> may\n> need additional power conditioning. But in any case, the widget power\n> supply should not add to the module power supply noise.\n>\n> There should be a simple way to disconnect the filter capacitors on \n> the\n> widget from the data lines when the widget is in Byte mode. Most \n> people\n> are not aware of this problem which was uncovered by another module\n> builder. It only effects those using the CAN-Do! in Byte mode.\n>\n> Using a synchronizing signal does not seem practical to us. It would\n> complicate the design of the widget power supply so that it would\n> function with or without the presence of the synchronizing signal (we\n> don't want to introduce a single-point-of-failure). It would\n> dramatically increase the satellite wiring harness complexity, \n> something\n> the widget was intended to a simplify. And it would inhibit the \n> widget\n> power supply from going into various power-saving modes.\n>\n> Recruit some new people into this project. Lyle simply doesn't \n> have any\n> time for doing new designs right now. We need a power supply designer\n> as stated above. And my time is limited. I'm willing to lay out the\n> new design and build a few prototypes, but I need others to do parts\n> procurement and volume building of widgets. I'll prepare flight units\n> if desired. We've talked about having someone skilled in parts\n> procurement before but I don't know of anything having come of it. \n> The\n> bottom line, if this is going to happen, Lyle and I need others to be\n> involved.\n>\n> If you think this is a good idea, or bad, please express yourself. \n> And\n> if you have other comments to add to the above, or would like to\n> modify/expand on above comments, please do so.\n>\n> Looking forward to your comments,\n>\n> Chuck and Lyle\n> _______________________________________________\n> Via the Eagle mailing list courtesy of AMSAT-NA\n> [email protected]\n> http://amsat.org/mailman/listinfo/eagle\n\n\n\n", "attachments": [ { "email": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/G6RVR67XIMLUOHSCXL3ICDWXMTYP43QS/?format=api", "counter": 2, "name": "attachment.html", "content_type": "text/html", "encoding": "iso-8859-1", "size": 18233, "download": "https://mailman.amsat.org/hyperkitty/list/[email protected]/message/G6RVR67XIMLUOHSCXL3ICDWXMTYP43QS/attachment/2/attachment.html" } ] }