Altair 8800 Again Project

[Dirk] posted a video (you can see below) titled, “Mystery Retro Project Start.” That turned out to be the first of a multipart series on his Altair 8800 Again simulator. The front panel appears to be laser cut and in some future video episodes, we expect to see him simulate the CPU with a Teensy.

There have been plenty of 8800 clones ranging from projects that recreate the original PCBs, to those that just run a Raspberry Pi inside. The middle ground will use an Arduino or some other small CPU to simulate the 8080 CPU.

The switches are multiplexed which isn’t uncommon. However, the LEDs are actually an addressable LED strip. We’ve built a similar panel with discrete LEDs and we can attest that using the strip is going to be easier. Besides that, it allows you to change the LED color to suit your decor, something the old 8800 could not do without a soldering iron.

The downside, of course, is that you can update the LEDs at exactly the same time. For most things that’s probably not going to matter much, but it is still a little bit of a departure from the original computer.

Even without emulation, this would be a good start for a panel to connect to SIMH running on a PC. The use of the LED strips and the laser cutter make this a lot easier than most other builds we’ve seen.

We always think about the Altair around the end of the year since the original showed up in the January 1975 edition of Popular Electronics (which would be on newsstands in December).

If you don’t have the patience to build a full front panel, you can put it on a PCB instead. In fact, we’d be tempted to build a series of PCBs to mount behind the panel. We’ve seen that approach a few times before.

6 thoughts on “Altair 8800 Again Project

    1. Ah yeah, those, just what I need to make individually addressable mini motored curtain track rollers to make my curtains with sewn in copper strips into a tuneable wifi diffraction grating to steer a beam sweeping the front yard for radar detection of snooping drones…

    1. You’re right about dim, but I think I had some green and orange LEDs in 1975. But I can’t remember for sure. When I did get other colors, they were floor sweepings, and not very bright.

      1. Yes, my uncle was getting hold of “seconds” of green, yellow, and red, (Didn’t meet spec, uneven brightness) LEDs in mid 70s, made a christmas light string out of them which was pretty unique at that time. I think they had to make 10 for every 1 that made spec those days and the good ones were expensive, and reds were a lot brighter for years.

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