Examples of ZX81 computer game screens

The Labor Of Love That Is Recovering Lost Software

At the beginning of the home computer revolution, the humble compact cassette was far and away the most popular choice for microcomputer data storage, especially on the European continent. As a volunteer at the Museum of Computing, [Keith] was instrumental in recovering and archiving the early works of Roger Dymond, a pioneering developer of early computer software in the United Kingdom.

In his video, [Keith] goes to great lengths detailing the impact that Roger Dymond had on the early home computing scene. After being let go from his council apprenticeship, Roger turned his attention to developing games for the ZX81, and later the ZX Spectrum. With the help of his family, he went on to run a moderately successful mail-order games publishing venture for several years. Increasing advertising costs and a crowded development scene saw Roger’s business become nonviable by 1983, but not before developing several gambling-style games and a standout Space Invaders clone.

Fast forward to 2021, and while some of Roger’s Spectrum software had been archived, much had been marked as ‘missing’ by online archivists. After further research, [Keith] realized that another potentially important tape had been forgotten about. ‘Games Compendium’ for the ZX81 had been completely lost to time, with the only evidence that it had ever existed coming from a 1983 advert in ‘Sinclair User’ magazine. Being written for the earlier model ZX81, the compendium would undoubtedly be of interest to software archivists and game historians.

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A Nokia 5110 playing a game

Firmware Modding Your Vintage Nokia Handset

These days we’re spoiled for choice when it comes to smartphone software, especially games. Official repositories for the leading handsets feature hundreds of thousands of games, and sideloading adds infinite possibilities. If you were lucky enough to be sporting a Nokia handset in the late 1990s, you probably had all of three games to choose from (and only one that was actually fun). [Janus Cycle] explores the steps needed to firmware mod your vintage Nokia phone, and how to expand on that paltry games library.

Enthusiasts have been modding their Nokia handsets since the 2000s, and the tools required now are the same as they were then. The Nokia 5110 and 6110 (as featured in the video below) use a proprietary cable and connector for communicating with PCs and other devices. Nokia’s official serial cable already opens up many possibilities for handset tinkering, including access to RAM and toggling Monitor Mode. This cable interfaces solely with the phone’s fast FBUS protocol, however firmware flashing takes place using the slower MBUS protocol over a single wire bi-directional pin.

The handset expects both serial ports to be available during firmware flashing. [Janus Cycle] demonstrates how to build a custom harness that connects both serial ports to a PC parallel port. At this point the flashing process is relatively straightforward, especially if you have an appropriately vintage computer to run the old flashing software.

Nokia owners may fondly remember changing the network name on the home screen to all sorts of inappropriate graphics, yet far more was possible with the right technology and know-how. It’s interesting to think about what may have been if softmodding was more widespread during the reign of the Nokia 5110 and its peers.

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Two circuit boards with bright seven segment displays

Retro Stereo SID Synth Looks And Sounds Sensational

Over the years, plenty of work has gone into emulating the Commodore 64 6581 SID chip, but as [SlipperySeal] puts it, nothing beats the real thing. His take on the MIDI SID-based synth not only sounds fantastic, but looks the business.

The 6581 SID arguably blessed the Commodore 64 with some of the best sound capabilities of any home computer in the 8-bit era (make sure to ‘sound off’ in the comments if you disagree). The 6581 was a three-voice analog synth with a dizzying array of settings. This was at a time when most home computers could just about manage a ‘beep’ of varying lengths and frequencies.

When you mix MIDI with the capabilities of the SID, you get something like [SlipperySeal]’s awesome looking synth, known as ‘Monty’. While the road to this point unfortunately resulted in several blown-up SID chips, the sacrifice seems to have paid off.

Realizing the limitations of having ‘just’ three voices, Monty is designed to use two SID chips in parallel, for a total of six voices in pleasing stereo sound. MIDI commands are transferred to the dual SIDs by way of an ATmega1284p microcontroller. The SID is well understood by this point, and [SlipperySeal] goes into great detail explaining the fundamentals of SID programming over on GitHub.

This isn’t the first MIDI synth that is based around the C64 SID chip, but [SlipperySeal] made sure that his stood out from the crowd. The seven-segment display centered on the board makes for a delightfully simple visualizer, an effect that looks even better when running two Monty boards at once, each responding to alternate MIDI channels (check out the video below). Naturally, we’re also fans of projects that include ominous, cryptic keyswitches.

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A Raspberry Pi next to a small circuit board

An Inexpensive FM Receiver For The Raspberry Pi

At this point, there are no shortage of impressive hacks for the Raspberry Pi. [Dilshan Jayakody] recently documented his experience in designing and building an inexpensive FM Stereo Receiver for the Pi platform, and the results are impressive.

Quite a few FM receiver projects center around the RDA5807 or TEA5767 ICs, however [Dilshan] has used the QN8035 by Quintic Corporation in his build. A handful of discrete components on a pleasing single-sided PCB is all that is needed to interface the QN8035 with the Pi’s I2C bus.

After demonstrating that the FM tuner could be, well, tuned at the command line, [Dilshan] then coded a smart looking GUI application that makes tuning a breeze. The software allows the listener to manually and automatically scan through FM stations, decode program service data, control the volume, and display the RSSI and SNR readings from the tuner.

As we reported earlier, FM radio is on a slow decline into obsolescence. This latest project isn’t aiming to break new ground, however its simplicity and inexpensive components are the perfect combination for beginner hackers and radio enthusiasts alike. More details can be found over on Hackaday.io. The schematic, source code and bill of materials can be found on GitHub.

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A computer green screen image of an IRC message of the day

IRC Server For MS-DOS

The recent flurry of projects based around Internet Relay Chat (IRC) should be a fair indication that the beloved protocol is not going anywhere. Now, thanks to [Mike Chambers], you can add to the IRC ecosystem by hosting your very own MS-DOS based IRC server.

This port of ngIRCd (Next Generation IRC Daemon) has already been spun up on 8088-based PCs running at just 4.77MHz, but you’ll still need at least 640KB of RAM. If your vintage IRC server takes off, you might want to think about dropping in an 10MHz V20 for a bit of a performance boost. Even so, it’s impressive that this server can get up on the 40-year-old IBM 5150, and should absolutely scream on an AT-class system.

The limitations of the 16-bit platform means that SSL and ZLIB are unsupported, and Mike has capped total connections at 50 in his port (however, this limitation can be adjusted by rebuilding from source, should you want to find out how far 640KB of RAM can take you). You’ll also need a few other things to get your server up and running, such as a packet driver for your network card and an mTCP configuration file.

Setting up your own IRC server is arguably a right rite of passage for most hackers and tinkerers, but getting this up and running on a decades-old beige box would make for a fun weekend project. [Mike] has all the juicy details on GitHub, and you can check out a test server running the latest build over at irc.xtulator.com.

Also, don’t forget to visit the #hackaday IRC channel over on irc.libera.chat.

[Thanks Sudos for the hot tip]

Apple II computer on a workbench

Simple Fan Controller Helps Apple II To Beat The Heat

In its day, the Apple II computer didn’t typically require active cooling. However, the increasing scarcity of replacement hardware convinced [Joshua Coleman] to come up with a more robust active cooling solution for his Apple II+, increasing the likelihood that it will keep on crunching numbers for decades to come.

Joshua mentions that he recorded temperatures inside his Apple II+ peaking at 110 Fahrenheit (over 43 Celsius). This isn’t totally unexpected for a fully-loaded Apple II system, and components were built to handle this – the original datasheet for the 6500 microprocessor family reveals that the CPU can handle temperatures as high as 158 Fahrenheit (70 Celsius). Unfortunately, we’re not dealing with brand new components anymore. Decades-old microprocessors don’t necessarily have the same thermal tolerance as they once did. All components will eventually wear out, and heat can certainly accelerate the aging process.

In the interests of maintaining his system, Joshua cobbled together an Arduino-based cooling system for his Apple II+. A temperature/humidity sensor continuously monitors the heat situation inside the case – when things get too toasty, a 12V fan powers up to draw fresh air over the logic board and expansion cards. A simple cooling curve reduces wear on the fan motor and relay.

This is hardly the first active cooling system for the Apple II line – in the 1980s, Kensington produced a popular (if not stupendously ugly) ‘System Saver’ accessory, an external bolt-on fan that kept things running cool. These were often deployed in schools and by power users looking for added reliability when maxing out the Apple II expansion slots, a configuration that could increase temperatures due to the extra power requirements and reduced airflow.

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A tiny robot with two wheels for sumo tournaments

Pint-sized Sumo Robot Is Adorable, Accessible And Totally Awesome

We’ve seen plenty of impressive robots of all sizes here at Hackaday, but recently we were particularly inspired by [Hans Jørgen Grimstad] and his thrifty mini sumo build.

Using the BBC micro:bit platform as a starting point, Hans seized the opportunity to build a competitive mini sumo bot without breaking the bank. According to his blog, the enchanting little machine uses commonly available parts and cost around $30 when built in 2020 (or $50 according to the more recent video, perhaps taking into account the cost of hardware in these trying times).

The results can be seen in the video below. Some sacrifices were made – Hans admits that the 3.3 V linear regulator gets a little toasty, but the design is kept much simpler by doing away with a switching regulator. The 700 RPM N20 motors are wired directly up to the 6 V battery pack, giving this plucky wrestler plenty of sumo-smashing power.

Hans hopes that the build can lower barriers to entry for new builders in robot tournaments, being something that can easily be put together in a garage or local makerspace for a low, low price. The mini sumo form factor is a great beginner or amateur project, made even easier when makers like Hans put all the nitty-gritty details up on GitHub. This is certainly not the first accessible sumo robotics project that we have covered, and it won’t be the last. We hope we see loads more of these endearing robotic gladiators at future events.

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