SRHuston Dot Net

Can you dig it? (yes, I can)
And I’ve been waiting such a long time
For today

–Chicago, “Saturday in the Park”

I mentioned previously that I had ordered a couple kits to assemble, and the first one – the Altair-Duino – arrived and got finished a scant few hours later (because I was so looking forward to it, and I stayed up a little too late playing with it, because it’s so freaking awesome).

[Note, in order to see captions on the photos, you’ll have to click through to the gallery on Google Photos; you’re not missing a hell of a lot this time though.]

The kit arrived Saturday early afternoon, and I set about earnestly unpacking it and checking things out. My youngest was in the process of finishing his own soldering project on my workbench so I knew I couldn’t start right away, which was fine – I’d need a bit of time to sort through all the parts anyway and make sure everything was there, and he’d been looking forward to his soldering project for a while and had started it Friday night after dinner. Everything was packed very well, and when pulling the parts from the box my first impression was the weight and quality of the metal frame for the unit, as well as the details on the front panel piece. The back panel is mostly clear acrylic with a small bit of black acrylic where the daughter card and VT100 emulator attach (more on that later). Overall I was already pleased with the kit.

After dinner and having sorted all the pieces, I look at what was before me. The parts list said I needed a 220k? resistor, but I had a 220? resistor. Reading forward in the instructions, and looking at the board, I found the ‘k’ was a typo in the parts list so I was good there. But it also said I should have 8 of the nylon bolts, and I only had four. Reading ahead, I wasn’t sure if I really needed all 8 – there was at least one spot where I saw they were used and then later removed. Either way, that wouldn’t be until the end stages of assembly so I figured I could forge ahead and worry about them later. Everything else checked out, so I started putting components to circuit board and it wasn’t very long at all before I had to warm up the iron.

Everything went on very easily. There was hints like putting the switches in place and then laying the front panel over them before soldering so that when you do they’re lined up side-to-side in a way to fit through the holes easily so you’re not surprised when it comes to final assembly, and another trick of installing all the LEDs into the holes, mounting the front panel, and flipping the whole thing over on its face with a satisfying “clack” while they all fall forward into their respective holes. A slight tap on one or two to get them to line up as well, and then you can solder every one in place – and all of them will be at the perfect height and angle to fit correctly on the front. Of course in the end when I was muscling things into place I ended up bending one of them the wrong way, but I was able to get it back pretty easily and everything looked fine in the end.

A few comments about the device itself. The brain of the whole operation is an Arduino Due which is preprogrammed with the software, which is easily reflashed if there’s a software update or you completely hose things and need to start over. There’s also an SD card with a bunch more software installed on it that can be loaded. The programming port is routed to the back panel with an extension panel-mount cable so you can always get to it easily for programming or powering it up, and the default serial connection from the Altair is routed to that connection as well. There are other options too, including one serial port that is also presented on the back panel, and another which connects to another card mounted on the back which contains a VT100 emulator running in a PIC microcontroller with a VGA port for display output and a USB port to connect a keyboard. I found I didn’t have the right cable to try connecting my VT320 to the serial port (I used to use it connected to my computer to receive syslogs, so the custom cable I have for it is a null modem), and I haven’t dug an old monitor out with a VGA port on it to try the VT100 emulator. Maybe I’ll do that in the next day or so, but then again the next project will be here on Tuesday so it might wait until after that.

What can be done with it? Well, it’s a clone of an Altair 8800, so anything you can do with that, you can do with this. I used the panel switches to enter in a couple programs and saw them work, and could demonstrate binary math and how assembly language works, how to debug a program by stepping through the code to look at the instructions entered, how to step through execution one step at a time to see how it works, etc. I even adjusted the internal settings so the emulated serial port would “act” more like a real serial port and spit out data to the terminal at a whopping 110 baud as it should be. Then I toggled in a bootloader, executed it, simulated loading a paper tape drive with 4k BASIC and hit play. Sure enough it took around 17 seconds for the first stage to load, then another 6.5 minutes while the second stage pulled in the data, finally outputting a satisfying “MEMORY SIZE?” to the terminal. I’m looking forward to exploring more about some of the operating systems that came and went before I got into computing, since my first foray into computing was an IBM PCjr with cartridge BASIC and PC DOS 2.10, right around when CP/M was making its exit.

Overall I’m extremely pleased with my choice. The kit is well designed and the manufactured parts done with precision, the instructions were easy to follow and the end result is a joy to play with and look at – so far everyone has commented that it’s one of the coolest looking things in the shack, and that’s while looking at an HF radio too. My only regret is that I didn’t buy the ESP-01S module that would provide for getting the device on my local network so I can just telnet into it; since I needed the nylon bolts that were missing from my kit, I asked if he could provide them with the module if I ordered it and he said yes, so that’s all on the way. I’ll have to decide if I want to commit to not using the standard serial port, or go through the process of soldering onto the TX/RX LEDs on the Arduino to basically squeeze one more serial port out of the device and have access to all three. I mean, I got it for hacking, why not hack right?

Part of me wants to make a video of using it or something, but I don’t feel like digging out a good camera to record it, or edit (because I’m a bit of a stickler for things being Just Right when it comes to that kind of production). Maybe the mood will strike me later.

Edit 2025/03/02: There’s three more photos at the end of the gallery from a follow-up addition which I cover in another post. Didn’t make sense to make a new album just for that.