Building The DIY HP41C: A Field Report

December 3, 2021 by Al Williams 21 Comments

I have a confession to make. I write about a lot of projects for Hackaday, but there are very few I read about and then go actually build a copy of it. I don’t have a lot of time and I’m usually too busy building my own stuff. But once in a while, something strikes my fancy and I’ll either raid the junk box or buy the kit. The most recent case of that was the PX-41C, a replica of the classic HP-41C.

The HP-41C is a somewhat legendary reverse-polish notation calculator. I still have my original HP-41C from 1979 (a very low serial number). It is still a workhorse but at 43 years old or so, I don’t like to leave it hanging around or near anything that might damage it. It has enough wear from the daily use it received 40 years ago. Sure, I have great emulation on my phone and I use that too, but the PX-41C kit looked fun, and with all through-hole parts it would be a quick build. The black Friday sale on Tindie sealed the deal for me.

Start-Up

The kit arrived on the Saturday after Thanksgiving, I decided to tackle it while waiting for some 3D prints. The components were all nicely bagged and marked. Tearing into the bags was a bit frustrating, but not hard and it did keep everything separate. There was a bill of materials, but — I thought — no instructions. Turns out the last part of the bill of materials is a link to some instructions. They aren’t much and I didn’t realize they were until after completing the board, but it isn’t hard to figure out. All the parts are marked on the silkscreen and you can probably figure it out — with a few caveats.

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Asus Motherboard gets CPU Upgrade Past its Specs

Clever Motherboard Hack Brings Late 90’s Motherboard Into The Early 2000’s

December 2, 2021 by Ryan Flowers 32 Comments

Some people look at specifications as a requirement, and others look at them as a challenge. You’re reading this on Hackaday, so you know where [Necroware] falls. In the video below the break, you’ll see how he takes a common mid-to-late 90’s motherboard and takes it well past its spec sheet.

A pull up resistor enables faster clock multipliers — [Necroware] does what all soldering iron ads think people do with soldering irons

Having already started with replacing the Real Time Clock with his own creation, [Necroware] looked for other opportunities to make the Asus P/I-P55TP4XEG more capable than Asus did. And, he succeeded. Realizing that the motherboard has the ability to have an external voltage regulator board, [Necroware] made one so that the Socket 7 board could supply more than a single voltage to the CPU- the very thing keeping him from upgrading from a Pentium 133 to a Pentium MMX 200.

While the upgrade was partially successful, a deep dive into the Socket 7 and Super Socket 7 documentation helped him realize the need for a pullup resistor on a strategic clocking pin. Then, [Necroware] went full Turbo and smashed this author’s favorite single core CPU of all time into the socket: the AMD K6-2 450, a CPU well beyond the original capabilities of the board.

It really goes to show that, of course, It’s All About The Pentiums. Thanks to [BaldPower] for the doing the needful and dropping this great hack into the Tip Line!

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Listening To The Sounds Of An 1960s Military Computer

December 1, 2021 by Moritz v. Sivers 44 Comments

Restoring vintage computers is the favorite task of many hardware hackers. Retrocomputing probably makes you think of home computer brands like Commodore, Amiga, or Apple but [Erik Baigar] is deeply into collecting early military computers from the UK-based Elliott company. Earlier this year he made a detailed video that shows how he successfully brought an Elliott 920M from the 1960s back to life.

It is quite amazing that the Elliott company already managed to fit their 1960s computer into a shoebox-sized footprint. As computers had not yet settled on the common 8bit word size back then the Elliott 900 series are rather exotic 18bit or 12bit machines. The 920M was used as a guidance computer for European space rockets in the 1960s and ’70s but also for navigational purposes in fighter jets until as late as 2010.

Opening up the innards of this machine reveals some exotic quirks of early electronics manufacturing. The logic modules contain multilayer PCBs where components were welded instead of soldered onto thin sheets of mylar foil that were then potted in Araldite.

To get the computer running [Erik Baigar] first had to recreate the custom connectors using a milling machine. He then used an Arduino to simulate a paper tape reader and load programs into the machine. An interesting hack is when he makes the memory reading and writing audible by simply placing a radio next to the machine. [Erik Baigar] finishes off his demonstration of the computer by running some classic BASIC games like tic-tac-toe and a maze creator.

If you would like to code your own BASIC programs on more modern hardware you should check out this BASIC interpreter for the Raspberry Pi Pico.

Video after the break.

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The Operator Input Device in a Minuteman II Missile Silo computer

Nuclear Missile Silo Keyboard Re-Launched In USB

December 1, 2021 by Ryan Flowers 14 Comments

When [jns] and their colleague came across an industrial or possibly military grade keyboard/trackball combo on eBay, their minds did the same backflips that yours or mine might. Enthralled by the specialty key caps, the custom layout, and companion trackball adorned with its own keys rather than buttons [jns] and his workmate they did the only thing that infatuated hackers can do: They each bought one! [jns]’s goal? Make it work via USB. Everything’s been documented in both software and in a very well done video that you can see below the break.

The OID in its natural habitat, a Minuteman Missile installation — The OID its its natural habitat, a Minuteman III installation (U.S. Air Force photo)

After doing some digging, they found that the keyboard and trackball combination was used in Minuteman III nuclear missile silos beginning in the early 1990’s, when the REACT program replaced aging cold war era computers and communications systems with simpler, more flexible systems.

Since the eBay auction came with only the keyboard and trackball, and not the entire Minuteman III outfit, using the new keyboard in its native habitat and wielding nuclear launch capabilities was right out the door. Instead, [jns] focused on reverse engineering the keyboard and trackball, collectively known as the OID (Operator Input Device) for use via USB.

In the video, [jns] goes into more detail about the discovery of reed switched keys, the RS422 protocol being used, blowing up an Arduino Pro Micro, and even repairing the aging trackball. Success was had, and he’s graciously shared the software and hardware design with the world.

If industrial and military grade control hardware gets your hacker juices flowing, you’ll not want to miss that time we covered a control console from a nuclear power plant for sale. Have you been working on any tantalizing, weird, obscure keyboards or equipment with far too many buttons and blinkenlights for your own good? Be sure to let us know about it via the Tip Line!

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Turbo Rascal Is The Retro Pascal Compiler We Always Wanted

November 30, 2021 by Zoe Skyforest 16 Comments

Pascal is not one of the biggest programming languages these days; it’s fallen into the background as the world moved on to newfangled things like C#, Python and Java. However, the language has its fans, one of whom put together a new compiler which targets retro platforms – and it goes by the name Turbo Rascal.

The list of supported platforms is extensive, with Turbo Rascal able to compile highly-optimized binaries for the C64, Amiga 500, BBC Micro, IBM PC, Atari ST, Game Boy, Amstrad, NES, ZX Spectrum, and more. There’s a usable IDE and even an included graphics editor for getting projects put together quickly. Also known by its full name of Turbo Rascal Syntax Error, or TRSE, it’s the work of one [Nicolaas Groeneboom].

The compiler runs on 64-bit Windows, Linux, and OS X, and there are extensive tutorial videos available on YouTube, too. Thus, there’s no excuse not to start developing a new retro game immediately. Check out the demo video below, and remember – as long as we keep using it, Pascal isn’t dead!

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Bring A Minitel Terminal Back To Life WIth An ESP32

November 25, 2021 by Jenny List 11 Comments

Most of us who are old enough are likely to have had our first experience of an online service some time in the 1990s, either through the likes of Compuserve or via an ISP. For our French readers the online experience will have come much earlier, as a forward-thinking telecommunications environment led to every household in the country receiving a viewdata terminal. The Minitel system as it was called was a runaway success, and was only finally turned off as late as 2012. Many of the terminals survive to make a great basis for projects, and it’s one of these that [Louis H] has taken and enhanced with an ESP32.

One of the special things about this project is that unlike so many other Minitel conversions it doesn’t involve tearing into the terminal itself. Instead the PCB plugs into the socket on the back of the unit and emulates the line for the terminal to talk to. It can then be used as an SSH terminal over WiFi, or as a serial terminal for the ESP32 itself for example running a MicroPython firmware. If you can handle the French AZERTY keyboard there is no easier way to drag a viewdata terminal into the 2020s, as you can see in the video below the break.

Chez Hackaday, we love these nostalgic gems from the 1980s. Indeed we like this classic French public network so much that we’ve featured it quite a few times. Here for example is a similar project using an Arduino. Continue reading “Bring A Minitel Terminal Back To Life WIth An ESP32” →

PicoMite Gives Your Pico A Deluxe BASIC

November 24, 2021 by Elliot Williams 57 Comments

What makes developing a microcontroller project quick and easy? Tops on our list are an interactive shell and comprehensive libraries that handle all the low-level peripheral stuff. You think we’re talking MicroPython? Not today! MMBasic has just been ported to the Raspberry Pi Pico dev board, and it has all the batteries included.

Just to give you a taste, it has built-in support for SD cards, all sorts of displays, touch screens, real-time clocks, IR remotes, numerous sensors, and of course WS2812 LED strips. And because all of this is baked into the BASIC, writing code to use any of these peripherals is straightforward.

Now, there’s BASIC and there’s BASIC. This is a modern BASIC: it has loops, functions, arrays, floating point, and a built-in full-screen editor. You connect to the Pico via UART, and you’re off to the races. If you’ve got a Pico sitting around, flash it and give it a try. Or check out the GitHub repository if you want to poke around in the internals.

This is a port of the BASIC that’s used on the Maximite virtual retrocomputer platform, which means that there are many working examples out there for you to crib from, and even a forum. Add in the incredibly nice user manual and tutorial (PDF), and you’ve got the perfect weekend afternoon.

Think MicroPython killed BASIC? Think again. BASIC is small enough that it can run where Python can’t, but that’s of course a more minimal experience. In contrast, MMBasic looks like it’s got all the toppings. The whole enchilada. It’s like BASIC Deluxe.