Let's Build a Video Card
eater.net
eater.net
Ben Eater is a fantastic teacher. You forget how different "knowing" and "teaching" are, until you get a great teacher!
Fast forward to now, when I've blown several hundred dollars on electronics supplies lol. Plus Ben has a great voice to listen to, so there's also that.
Instead I got completely sucked in. His explanations were so clear I was able to understand the majority of the process and could possibly even replicate it or guess at the next step after watching for a bit. I felt like I learned more in that 30 minute video than I did in my whole year of high school electronics that scared me away from this sort of thing twenty years ago. My interest in doing some small projects is definitely piqued now.
On an old church projector, there was a button on the remote so I could freeze the screen. Then I could switch from PowerPoint to QuickTime Player (or whatever else) without disturbing everybody who was watching. Newer equipment (some projectors, most TVs) lack this feature. I'd like to build a box that stores the current frame in RAM, and has a simple toggle switch between the stored frame or the live video feed.
After a recommendation for the NeTV, I asked bunnie, and he said that the NeTV2 is a good choice for HDMI. It's pretty expensive though, and doesn't support HDCP.
https://github.com/AlphamaxMedia/netv2-ideas/issues/21
If anybody else has some guidance about how to proceed with this project, or some mutual interest that could translate into nagging me to actually do it, please get in touch!
NETV2 (Libre mode) is probably the best bet for hardware that will both do the job and has at least some example stuff that will be similar. It's FPGA based, but it will require a lot of effort to implement.
Other than that you are looking at the HDMI or DVI TxRx cards along with an FPGA dev board. Terasic's Altera boards and expansion cards, for instance will do the job and they offer VGA, DVI and HDMI interfaces for a large number of their dev boards. Anything along this vein will cost a lot more than NeTV2
IMO If you want to rely on something for a large commercial public presentation, I really wouldn't hack something together. Just buy a presentation switcher.
I'm currently working on a homebrew Z80 computer. I'm at the stage of moving the preliminary designs to PCBs, but from my experience, wirewrapping is a lot better than breadboarding when you start building circuits with many signal wires. Breadboards are quick and simple at first when you can "plug and play", but it would quickly become a nightmare when the number of connections and wires exceed 200. It may be a less concern for a modern microcontroller as i2c and SPI are serial interfaces, but on a 8-bit computer, you'll hit this number really quickly, because the system bus is 24-bit (16-bit addr, 8-bit data), parallel. A bus driver using two unidirectional buffer has 24 x 2 + 8 = 56 wires, two RAM chips have 48 wires, a ROM has another 24 wires, it's already 148 wires now for a bare-minimum system without even an I/O port. It will get out of control soon. Also, a 16-bit machine will become a nightmare even quicker as they have 32-bit bus.
On wirewrapped boards, you'll never get a bad connection without any visual clue, the connection is as solid as soldering, and there are no jumper wires hanging in the mid-air to stop you from probing it using an oscilloscope. Strongly recommended, to learn more, search keywords "wirewrap electronics" at YouTube.
You're severely underestimating the cost of wire-wrap sockets. They're a low-demand item, so they're rather expensive; a few dollars for each socket is typical, and DIP40 sockets can get into the $10 range. (The sockets will cost more than most of the parts in them!)
Which is why getting them from China is a good idea. I'm building the real thing and I'm well aware of that, but I've found a very economical solution: I've found that buying single-row 40-pin sockets, like this one (https://www.aliexpress.com/item/32959627004.html), is a good low-cost alternative to wirewrap sockets, it only cost you one dollar each.
It's not extremely easy to use, as you have to cut them and manually plug two rows of them to make a poor-man's DIP header, but not difficult either, and doing it is straightforward. Also, if the socket is too rough for the components you need (for example a heavy ZIP socket, or a DIP-40/64 chip), I found you could install the wirewrap DIP header to the board first, then plug a generic, cheap DIP socket on top of it, then plug your ZIF socket on top of those.
The only real disadvantage is the increased weight and height, so the solution is not very elegant, but hey, one 40-pin header only costs you one dollar, 10 dollars buy you ten 40-pin headers, which is good for ~15 chips!
Personally, I found my bread board circuits more aesthetically pleasing and easier to reason about. I had 4 different colors of wire, I always ran my wires in the cleanest manner possible using the most direct and shortest wire.
Probably the most complicated bread board circuit I wired up was an 8KB RAM bank for a 16bit microcomputer. My only real wire wrap project was when we prototyped an MP3 player driven by an AVR.
This is no longer a problem today.
> using the most direct and shortest wire.
Unfortunately, it's often not even possible! A DIP-40 chip already occupies most columns, leaving only two or three columns for wiring. Impossible to wire the bus directly...
Breadboards offer a huge amount of flexibility over veroboard, at the expense of size and permanence.