Running FreeDOS And 8086tiny On The Game Boy Advance Because You Can

June 5, 2025 by 21 Comments

How many people haven’t looked at their Game Boy Advance (GBA) handheld gaming device and wondered how much better it might be if it could run FreeDOS. Inside an 8086 emulator. If you’re like [ZZAZZ] and similarly suffer intrusive project-related thoughts, then this might be a moment of clear recognition, somewhat like sharing one’s story at a Programmers Anonymous meeting, but we digress.

In the video, the basic premise of making even the 8086tiny emulator work on the GBA seemed improbable on the outset – courtesy of the rather limited memory environment provided by the GBA – before even daring to look at things like disk access.

However, letting silly things like segmented memory and mismatched memory addresses deter us from pleasing said intrusive thoughts would be beyond the pale. Ergo we get a shining example of how days of rewriting code, stripping code, debugging code, fixing alignment issues in code and writing work-arounds for newly discovered issues in code can ultimately lead to the proud moment where FreeDOS boots on the GBA.

Granted it takes over an hour to do so, and has to be started from a butchered Pokémon Emerald save file, courtesy of a well-known exploit in that game, thankfully preserved in counterfeit cartridges.

Admittedly we’re not sure what practical applications there are for FreeDOS on the GBA, but that’s never stopped hackers from taking on impossible projects before, so there’s no sense letting it get in the way now.

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Passive Saturation Box Is A Cheap Way To Distort Your Sound

June 4, 2025 by 10 Comments

Distortion pedals and overdrive effects usually have a bunch of lovely transistors or op-amps inside and lots of knobs and dials to tweak the sound to your personal taste. However, it’s possible to get some crunchiness in your audio signal without all that fuss, as [Simon Hutchinson] demonstrates with his $2 “analog saturation box”.

The effect is achieved quite simply by installing a pair of diodes in opposite orientations, connected from the signal path to ground. This configuration is also known as wiring diodes in “anti-parallel.” When the signal increases in amplitude beyond the diode’s forward voltage, the diode conducts and the signal’s peak is clipped off, which creates a distorted tone. Since there are two diodes, one in each orientation, both the tops and bottoms of the AC audio signal are clipped in this manner.

The amount of clipping is highly dependent on the diodes chosen and the strength of the signal you’re working with. Silicon diodes clip around 0.7 V, while germanium diodes clip at about 0.3 V, but that doesn’t give you much flexibility. You can work with this to some degree, though. You can up the minimum clipping level by stacking more diodes in series in each direction, or you can put in a potentiometer to vary your signal’s level before it hits the diodes. Really, though, this hard voltage limit is why more commonly, we use active distortion or overdrive effects that have more options for gain and level and such.

[Simon Hutchinson] does an able job of explaining the effect and demonstrates its use with some simple beats. As a passive device, it’s pretty one note—there’s no EQs to mess with the frequency response, and no ability to change anything else about the sound, either. Still, it’s interesting to hear the effect it does have on a signal, and you might just find this is all the distortion you need. If you’d rather go into full-fat distortion though, we’ve covered that too.

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Slide Rule By Helix

June 4, 2025 by No comments

It is no secret that we like slide rules around the Hackaday bunker, and among our favorites are the cylindrical slide rules. [Chris Staecker] likes them, too, and recently even 3D printed a version. But spurred by comments on his video, he decided to try something that might be unique: a helical slide rule. You can see how it works in the video below.

With a conventional slide rule, the scale is rotated around a cylinder so that it is the same length as a much longer linear scale. However, this new slide rule bends the entire rule around a cylinder and allows the slide to move, just like a conventional slide rule. If you have a 3D printer, you can make your own.

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A circuit board is shown, with the tip of a soldering iron applied to a piece of solder wick positioned above a pad.

Making Solder Wick Less Painful

June 4, 2025 by 28 Comments

For some people (e.g. this author) solder wick is a tool of last resort. Unfortunately, solder suckers and vacuum pumps lose most of their utility when you move from through-hole to SMD components, forcing us to use the dreaded wick. For those of us in this mindset, [nanofix]’s recent video which we’ve placed below the break on tips for solder wick could make desoldering a much less annoying experience.
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Adding Assistive Technology To A Doorbell

June 4, 2025 by 4 Comments

The advent of affordable computing over the last few decades has certainly been a boon for many people with disabilities, making it easier to access things like text-to-speech technology, automation, or mobility devices, and even going as far as making it easier to work in general by making remote work possible. Some things still lag behind, though, like user interfaces that don’t take the colorblind into account, or appliances that only use an audio cue to signal to their users. This doorbell, for example, is one such device and [ydiaeresis] is adding features to it to help their mother with some hearing issues.

The first thing up for this off-the-shelf remote doorbell is a “brain transplant” since the built-in microcontroller couldn’t be identified. There are only a few signals on this board though so an ATtiny412 made for a suitable replacement. A logic analyzer was able to decode the signals being fed to the original microcontroller, and with that the push of the doorbell can be programmed to do whatever one likes, including integrating it with home automation systems or other assistive technology. In [ydiaeresis]’s case there’s an existing LED lighting system that illuminates whenever the phone rings.

Although it would be nice if these inexpensive electronics came with the adaptive features everyone might need from them, it’s often not too hard to add it in as was the case with this set of digital calipers. To go even further, some other common technology can be used to help those with disabilities like this hoverboard modified to help those with mobility issues.

Thanks to [buttim] for the tip!

The Blackberry Keyboard: How An Open-Source Ecosystem Sprouts

June 4, 2025 by 43 Comments

What could happen when you open-source a hardware project?

No, seriously. I hold a fair few radical opinions – one is that projects should be open-source to the highest extent possible. I’ve seen this make miracles happen, make hackerdom stronger, and nourish our communities. I think we should be publishing all the projects, even if incomplete, as much as your opsec allows. I would make ritual sacrifices if they resulted in more KiCad projects getting published, and some days I even believe that gently bullying people into open-sourcing their projects can be justified. My ideal universe is one where companies are unable to restrict schematics from people getting their hardware, no human should ever hold an electronics black box, by force if necessary.

Why such a strong bias? I’ve seen this world change for the better with each open-source project, and worse with closed-source ones, it’s pretty simple for me. Trust me here – let me tell you a story of how a couple reverse-engineering efforts and a series of open-source PCBs have grown a tree of an ecosystem.

A Chain Of Blackberry Hackers

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