Next Project Update
Added 2020-10-14 01:14:39 +0000 UTCHello, I know it's been a while since I've had a video ready but it's been one of those projects that keeps feeling like it's going to over after just one more thing and then another thing pops up after that.
I built a new VGA capture system with proper VGA capture hardware this time. I've got an Epiphan DVI2PCIe and a Datapath VisionRGB E1s in it. Both were are supposed to be compatible with Linux and I've had no end of problems getting them set up. I've had to contact customer support for both cards and one of them turned me down saying it's too old and the other has kind of left me hanging.
I could make it work on Windows using the Epiphan card, but their drivers are effectively broken on linux at this point. I'm starting to think the Datapath is a better card to use in the long run though. It works perfectly for everything except some 640x480 sources in both Windows and Linux. I'm hoping to get help from Datapath on this issue because they still sell and support the card. But since they haven't got back to me in about a week I'm trying to solve it on my own.
In the picture here I'm measuring the VGA signals on my HP16500C. The problem I'm having is a known issue in the capture communities where 480p sources can have a vertical offset. So I'm going to try to modify the V Sync signal going into the capture card to correct this problem. I'm planning on going into this process in a lot of detail in the video covering all this. I bought another analog/oscilloscope card for the analyzer system so I can capture 4 sources at once which will let me visualize the full VGA signal set in real time as I talk about it in the video. It's still in the mail but when it gets here I'm going to finish whatever I have ready up to that point as a video. I'm very likely to have a followup video about the V Sync modification process so there isn't as much of a rush to get that done for this.
I've tried to start a few other projects to get something done and published during this process but it's been my complete focus and hard to pull myself away from. I'm learning I'm really bad at long term multitasking and it's really hard for me to switch gears to another project. It just ends up with me delaying it for months. And I really feel like I'll not get back to this if I don't do it next.
Comments
The LCD idea is what I was originally trying to do, but this is a much better solution once I can get it fixed. (I actually just hit on the diagnosis I think and posted about it in #s-tech on discord). I have a plan to fix it, so if that works this should be perfect. In the video I'll cover some more info on the LCD idea because I almost had a perfect setup for it but had an issue at the last possible moment. I responded to Dinty76538 with some info on the Data Generals that will probably answer some of your questions about it.
Tech Tangents
2020-10-14 04:14:03 +0000 UTCThe Data Generals are a significant undertaking that is much harder to dive into than something like a desktop. Documentation is sparse, replacements are rare and expensive, and most of the parts are too heavy for me to move on my own. So working on it takes planning, resources, and having someone come and help me move the parts. I have started working on the terminal which is simpler and I do really need to finish that up. That will be the next thing I talk about and it shows why for me it's going to take a long time to safely get those computers running again.
Tech Tangents
2020-10-14 04:13:09 +0000 UTCI wish you the best of success with the VGA capture. I do wonder one thing, I know it would be a terrible hack, but would the guts of a modern LCD screen VGA input to digital processor be something of value on this project? I don't actually know how an LCD process the signal but I do wonder if there is a way to tap into that. Just a thought and probably not a good one. I do second a follow up on the Mini-Computer. That was SUPER interesting. Even if it is just a little teaser, I would be all about it, but I am probably not into what most are.
CubicleNate
2020-10-14 03:57:14 +0000 UTCI'd love to get an update on the Mini Computer.
Dinty's Hideaway
2020-10-14 02:53:35 +0000 UTC
