I stopped mine because my intent was to explain the logic of the Z80 from another person's reverse engineering into logic blocks for use in a FPGA and when I got to the Program Logic Array that decodes opcodes he wrote it in python. The python was quite extensive and I felt it would be too time consuming to figure out the logic. I did get permission to use his reversed engineered schematics and since he made it freely available I felt it was only fair that mine was free as well.

I have decided to do more background work before moving on so I'm using a logic simulator, LogiSim-Evolution and the book Build your own computer from scratch to get more familiar with the architecture and logisim. I also found various sites building a cpu for a FPGA.

The next few months I'm going to research this then attempt a COSMAC 1802 then a Z80 in LogiSim and if successful I'll do a rewrite for building a 1802 and Z80 in LogiSim. The LogiSim-Evolution version has a fpga export function that can be customized for specific boards.

Quote from: JKnightandKARR on Today at 01:11 PMHope it has the rubber feet on it still... pretty needed i think...  but yeah I am really happy with the machine, and it can self update. Lol

Yes, the guy who sold it (interestingly, his name is Chris ) says that it still has the rubber feet. He also mentioned that it moves like crazy - like your video showed.

Quote from: JKnightandKARR on Today at 01:11 PMWhich 1 was ya giving her Neptune 2 or Centauri Carbon? Both good machines in their own ways.

I'm planning on giving her the Centauri Carbon, but there is a small chance that she will request the Neptune 2, because her favorite brother (Ken) has the Ender 3, and she may want that. I will recommend the Carbon, but leave it to her (assuming that I can get the Neptune working well.)

Quote from: granz on Today at 06:06 AM

Quote from: JKnightandKARR on Aug 01, 2026, 09:33 PMCopy Cat...... lol Couldn't resist.

Actually, you are a big part of the reason that I looked into that printer. Your satisfaction with yours made me decide to get it.

Quote from: JKnightandKARR on Aug 01, 2026, 09:33 PMI am going to upgrade mine with the 4 in 1 Canvas tool. Only $55 to upgrade to 4 color printing.

I did not know about that - the Canvas Tool seems like a great idea. I think that I will get the printer, as is, and give it to my daughter. Then, after she gets used to a printer, I will mention the Canvas Tool, and let her buy it, herself. Thanks.

Hope it has the rubber feet on it still... pretty needed i think...  but yeah I am really happy with the machine, and it can self update. Lol

Which 1 was ya giving her Neptune 2 or Centauri Carbon? Both good machines in their own ways.

I saw this posting in the RetroComputing forum, and thought about your book:

https://retrocomputingforum.com/t/hello-i-wrote-a-book-about-the-z80/6319

It looks like he will be selling it; maybe you could get a few bucks from your book.

Quote from: JKnightandKARR on Aug 01, 2026, 09:33 PMCopy Cat...... lol Couldn't resist.

Actually, you are a big part of the reason that I looked into that printer. Your satisfaction with yours made me decide to get it.

Quote from: JKnightandKARR on Aug 01, 2026, 09:33 PMI am going to upgrade mine with the 4 in 1 Canvas tool. Only $55 to upgrade to 4 color printing.

I did not know about that - the Canvas Tool seems like a great idea. I think that I will get the printer, as is, and give it to my daughter. Then, after she gets used to a printer, I will mention the Canvas Tool, and let her buy it, herself. Thanks.

Quote from: granz on Aug 01, 2026, 03:37 PMMy son, Ken, has an Ender 3, of which the Neptune 3 is a clone. The printer that I wanted to give to my daughter is that old Neptune 3, that I got from Joe in a trade. Ken likes it, but often talks about how it is a tinkerer's printer. Just this morning, I watched a YouTube Video where the guy talked about the Ender 3, and how it is really a tinkerer's printer. "If you like to tinker, you will really like the Ender 3." Now, my daughter is many things, but a tinkerer she is not. And, she wants her eleven-year-old daughter to run the 3D printing.

So, I decided that, while it's a good printer, I'm not giving that Neptune 3 to my daughter. So, I got back on OfferUp and found a "like new" Centauri Carbon for only $140. So, I put in an offer for it, and he accepted. We are meeting at a KFC which is on our way home from Church, so I don't even have to go out of my way to pick it up.

Copy Cat...... lol Couldn't resist. I hope it gives you plenty of good prints. I am going to upgrade mine with the 4 in 1 Canvas tool. Only $55 to upgrade to 4 color printing.

Quote from: granz on Aug 01, 2026, 03:37 PMNow, back to figuring out what to do with the Neptune - sell it, or fix it up and use it.  I really need to find some way to make some money from my printers. Now that I have an accidental print farm, does anyone need outsourced printing?

I've thought of if I could turn a 3d printer into a laser cutter/engraver or a CNC mill....

Hack-A-Day had an article this morning about running a simple 3D CAD program in your browser. It looked pretty cool, but it referred to an earlier HaD article about a completely local CAD program, very much like TinkerCAD.

https://hackaday.com/2025/10/25/what-if-tinkercad-was-self-hosted/

The program is called CaDoodleCAD, and I downloaded the stand-alone (don't need to install it) version from their web site (https://cadoodlecad.com/.) You need to select your operating system, and the site then takes you to a grid of donation options. You do not need to donate, although after playing with this, I probably will. After you select your payment option, it appears that the page has not changed - just scroll up to find the download options. For Linux, I just downloaded the X86 AppImage straight to my desktop - this is the stand-alone version, that does not need to be installed. You need to mark the file on your desktop as executable, and then just double-click to launch the program. Supposedly there is also a stand-alone Windows version, but I have not explored that.

I played with the program for about fifteen minutes, trying to make a case for my  original (3.5") smart watch. I realized that I was probably starting too high, and decided to switch to a lower-hanging fruit. There is no file-save option, you just have a bunch of projects in your "Project Manager" - click on "Home" in the upper-left corner of the program window.

So, I started a new project for a simple keychain:


This is the print after about another fifteen minutes (I did not use any tutorial, or manual) of playing around.

I had just purchased a set of keychain rings and put one on the print. Marilyn really likes it, so that is a win right there.

There are a couple things that I want to work on (maybe finding a tutorial would be good ):

• Position the hole closer to the edge of the print
• Make the text a little less thick (it stands out a bit too much)
• Make the text a different color
• Round off the corners a bit

Overall, I think that this is pretty good for playing with a new CAD program, with no manual and no tutorial - it only took me about fifteen minutes of playing around. This is going to be my new CAD for quick-and-dirty 3D designs; at least until I get a need for more complex stuff.

My son, Ken, has an Ender 3, of which the Neptune 3 is a clone. The printer that I wanted to give to my daughter is that old Neptune 3, that I got from Joe in a trade. Ken likes it, but often talks about how it is a tinkerer's printer. Just this morning, I watched a YouTube Video where the guy talked about the Ender 3, and how it is really a tinkerer's printer. "If you like to tinker, you will really like the Ender 3." Now, my daughter is many things, but a tinkerer she is not. And, she wants her eleven-year-old daughter to run the 3D printing.

So, I decided that, while it's a good printer, I'm not giving that Neptune 3 to my daughter. So, I got back on OfferUp and found a "like new" Centauri Carbon for only $140. So, I put in an offer for it, and he accepted. We are meeting at a KFC which is on our way home from Church, so I don't even have to go out of my way to pick it up.


With all the things going so perfectly (good beginner's printer, great price, not going out of my way to pick it up, all this today,) I think that God wants this printer for my daughter. So, tomorrow, I'll pick it up and Monday I'll put a spool of filament on it to test it. Then, I'll order a selection of filament, like the ones that I got for myself and Peter, and then get it over to my daughter's place and teach my grand-daughter about printing.

Now, back to figuring out what to do with the Neptune - sell it, or fix it up and use it.  I really need to find some way to make some money from my printers. Now that I have an accidental print farm, does anyone need outsourced printing?

Nice, I hope that you can get your score up enough to get into the math classes that will be best for you.

I when to my school today to take my math placement test, I didn't do very well I got a 15 but they said I could take it four more times and I have to do 5 hours of practice before I can take it again and the math coach told me to do only one hour a day at the most and he said I could go to the school and the math coaches can tutor me. Next week I plan to go to the school every weekday to practice and retest on next Monday.