The style and sound of older video games is unique enough that they’re still copied in relatively modern games like Undertale, Celeste, or Shovel Knight. There’s also a vibrant chiptune community making music on the older hardware directly. Often this involves hardware modding or otherwise finding chips from older gaming systems to replicate that unique retro gaming sound authentically. But disassembling older systems is not always necessary. Take a look at this Game Boy Advance synthesizer which uses the GBA hardware with no modifications at all.

The key to making this work is the GBA’s multiboot feature, which allowed these systems to send executable code over a link cable to other consoles which didn’t have cartridges. This meant that friends could play multiplayer games without each one needing their own cartridge, but it also means that nowadays people can send their own custom software directly to the console’s RAM without much extra effort. To run the synthesizer software, the GBA is connected to a computer, the software is started, and then when the GBA is powered on the snythesizer is automatically loaded into its RAM. The audio output is played over the headphone jack, and various controls are available on the computer and on the console.

In the video linked below, [Andy] is using the GBA with some other musical hardware and the sounds he’s getting from the unmodified console are impressive. It could certainly be a go-to for anyone interested in getting started in this style of music or who doesn’t want to do something like take apart an original Sega Genesis for the audio circuitry.

The RepRapMicron (also µRepRap) is pretty much the microscopic take on what RepRap did for more macroscale manufacturing, with the most recent innovation being a UV print head, called the PIKA UV Head. What this does is use off-the-shelf optical fiber and UV LED modules to create 3D structures in-situ in a UV resin, allowing for pretty small structures to be printed, down to a resolution of about 9 µm.

More photos of prints can be found on the blog page with links to YouTube videos. It’s naturally somewhat tricky to get clean photographs of a 3D print that’s small enough to lose forever if you so much as sneeze or breathe too loudly.

For the UV head assembly a single mode fiber optical cable was used in the form of a regular patch cord that got trimmed a bit with a hacksaw. This was used in combination with a “3W” UV LED module, which may or may not be its true rating, but it was definitely able to cure the SLA resin. The used resin was regular eSun Standard Resin.

Afterwards you have to do the typical SLA post-processing, including cleaning off of liquid resin – both the part and fiber – and curing the part. So far results are pretty decent, with overhangs still being a weak spot that will be addressed in future revisions.

Anyone who’s ever built their own motors knows how tedious winding the coils soon becomes; in [Larry]’s case, the issue was even worse. He’s building his own flip-dot matrix display, and each dot uses two electromagnetic coils to flip a magnet in the dot. Rather than wind each of these by hand, therefore, he built his own coil-winding machine.

The coil winder uses two stepper motors: one to wind wire onto the bobbin, and one to move the wire guide carriage back and forth, distributing the wire evenly across the bobbin. The bobbin is held in place by a retainer, which doubles as a tie point for the end of the wire. The spool of wire rotates on a pair of bearings, and the wire is fed between two pieces of foam to provide adjustable tension. The housing is mostly 3D-printed, with some metal rods, bearings, and belt drives fleshing out the structure. On the electronics side, a Teensy controls the winder, with an OLED display and a rotary encoder for control. Before beginning on a coil, it homes the guide carriage against an end-stop switch, then winds on layers, keeping track of the number of layers applied.

We’ve seen a few coil winders here in the past, including a 3D printer adapted to winding stators. For more on this winder’s application, check out [Larry]’s flip-dot design.

The Chinese had been using large crossbows – akin to Greek and Roman ballistae – for warfare for many of the same reasons that European armies loved them. Their single, large arrow was effectively unstoppable, though this also was rather useless against large groups of infantry unless they were so kind to neatly line up. Old Chinese records mention a special kind of ammunition, called a cup arrow, or ‘storm of crows’, which involves launching many smaller arrows instead of a single large one, a feat that [Tod] really wanted to try and recreate.

In itself this doesn’t sound too complex: just grab some arrows, loosely tie them together in a bundle and slap them on the crossbow. Yet with the immense forces applied on this bundle it clearly turns out that the engineering challenge isn’t quite that straightforward, as the arrows love to scatter wildly in all directions or otherwise be rather unpredictable.

Although we can find historical references to multiple bolt siege crossbows being used, details are sparse on how the Chinese engineers addressed these aforementioned issues, so [Tod] tries a range of approaches to try and make it work on his own siege crossbow. Unfortunately he wasn’t able to make it work reliably, but he says he’ll be back with a range of improvements, with the community invited to pitch in their own ideas.

These type of weapons were very commonly used in China and surrounding nations from hundreds of years BCE to around the 16th century CE, when black powder was used to launch projectiles like fire arrows from a Huo Che or the Korean equivalent of the Hwacha, effectively multiple rocket launchers, not unlike the MLRS units seen in militaries today.

The Philips CD-i is a console with many shortcomings, and those include the power supply. For whatever reason, the engineering team decided it should use an 8P8C connector just like Ethernet. Thus, just like your Ethernet cables, it has that annoying problem of the tab snapping off all the time. [MattKC] wondered if the CD-i could benefit from a USB power upgrade instead, and set about making it a reality.

The plan was simple enough—get the CD-i running off of USB-C instead of the ungainly original power supply that shipped with the unit. Given the console runs almost exclusively off of 5 V power, it should have been pretty easy. Only, the original spec adds one little detail that makes things a bit harder. The console is designed to draw up to 3 A from the 5 V line, while also having a -5 V line at 0.2 A. If not for that negative supply, it would have been easy to run the unit off any old 15 W USB-C charger spitting out 5 V. That extra negative line complicates things, because while the negative line could be created with some supporting electronics, it’s hard to find that extra watt from most chargers. While there are plenty of higher-wattage USB-C chargers, the majority tend to use higher voltages to deliver the additional power, capping the 5 V output at 3 amps.

Thus, it was necessary to work a little harder. [MattKC] decided to build a board that would negotiate with a USB-C charger for 9 V operation to get the power budget necessary. This would then be stepped down to 5 V, while there would also be an inversion step to supply the -5 V line, too. A CH221K chip does the job of negotiating a 9 V USB-C power supply, while a TPSM84538 steps the voltage down to 5 V with the capacity to supply up to 5 A. An LT3580 chip then inverts this voltage for the 5 V line. There’s also a power switching circuit on board because the CD-i included some of that functionality in the original power brick.

If you’ve got a CD-i and you’re sick of fussing with the original power supply, this could be a great upgrade. We’ve also explored USB Power Delivery in detail before, if you need a primer.

Hackaday Editors Elliot Williams and Al Williams met to review the week in Hackaday. Turns out, it was a week for tiny things, cybersecurity, nostalgia, and projects that would have been nearly impossible for the average hacker not that long ago. But first, you can hear a little about the upcoming Supercon badge and the trials of importing and exporting parts for the badges.

How many props does your drone have? [Joshua] has one. Want to fabricate semiconductors at home? Do you have a microwave? What about using NFC in your next project? There’s all that and more in this episode.

The quick hacks include a request from NASA for ideas (and, yes, there is prize money) and slide rule tricks, among other things. For the can’t miss articles, the cybersecurity weekly got some appreciation and Al took a trip down memory lane at the Altair 8800 he always wanted.

Check out the links if you want to follow along, and as always, tell us what you think about this episode in the comments, or drop us a line on the mailbag.

Download in DRM-free macroscopic MP3.

Episode 392 Show Notes:

News:

• Supercon Ten Tickets On Sale Now
  • The Trials And Tribulations Of Your First Badge
  • PHP2Shell — AI uncovers critical vulnerabilities in the backbone of the web

Mailbag:

• Thanks to [Silver Dog Australia] for some new sting sounds for the podcast. Send us your sound, questions, or thoughts on the podcast for next week’s mailbag: mailbag@hackaday.com

Interesting Hacks of the Week:

• Building A Flying Drone With A Single Propeller
  • Building And Flying A Helicopter With A Virtual Swashplate
  • Flies Like A Quadcopter, But This Drone Design Has Only One Propeller
  • One-Motor Drone Mimics Maple Seeds For Stability
• Making Photovoltaic Solar Cells With A Microwave
• A Stereo Vision Board For Hardware Hackers
  • I’m not putting a WiFi router into a phone charger (Part 3) – Rootkit Labs Blog
  • Stereo Vision And Depth Mapping With Two Raspi Camera Modules
  • High Performance Stereo Computer Vision For The Raspberry Pi
  • Tracking Bees With A Stereo Camera
  • Building The First Digital Camera
• An Open Micro-Manipulator Improved
• Building A Microscope With A 3D View
• Birduino Plays Bird Calls On Demand With NFC-enabled Cards

Quick Hacks:

• Elliot’s Picks:
  • NASA’s Lunar Ground Challenge is a Real Buzz
  • 5 GHz Drone Video, With An ESP32
  • Going Whole-Hog On A First Satellite Ground Station
• Al’s Picks:
  • Simplifying Slide Rule Calculations With Trig
  • An LCR Meter With Compromises
  • Visualize Regular Expressions With Marbles

Can’t-Miss Articles:

• This Week In Security: Critical DNS Keys Rotated, Hacking Freezers Isn’t Cool, OpenAI Spies On Itself, And Advanced Hardware Wallet Hacks
• The Age Of Altair

If we’re honest, there aren’t a whole lot of accessories coming out for the MSX computer line this holiday period. There is, however, a new sound expansion cartridge for the diehard fans out there, thanks to [Ricardo Suzuki].

It’s called the Misato MSX, and it’s a cartridge you can build yourself to give your computer a grander set of sound capabilities than it ever had before. At the heart of the cartridge lies the Yamaha YMF288, an OPN3 chip that offered three Software Sound Generator (SSG) channels, six FM channels, and six rhythm channels. Paired with a decent DAC chip, it provides deliciously rich synthesized sound very characteristic of that 1980s/1990s FM synthesis era. The cart can be used for play of a wide variety of OPN music, or creating your own compositions with the right software tools. Audio output can be had either from the stereo line out jack on the cart itself, or mixed down to mono and passed to the MSX’s internal mixer.

If you’ve got an MSX that is a little weedy in its sound capabilities, this cart could be just the thing you’re looking for. We’ve looked at some fun MSX machines before, too. If you’re cooking up your own upgrades for retro machines, don’t hesitate to let us know on the tipsline!