Reusing An Old Android Phone For GPIO With External USB Devices

November 4, 2024 by Maya Posch 44 Comments

Each year millions of old smartphones are either tossed as e-waste or are condemned to lie unloved in dusty drawers, despite the hardware in them usually being still perfectly fine. Reusing these little computers for another purpose once the phone’s manufacturer drops support is made hard by a range of hardware and software (driver) issues. One possible way to do so is suggested by [Doctor Volt] in a video where a Samsung Galaxy S4 is combined with a USB-connected FT232R board to add external GPIO.

The idea is pretty simple: the serial adapter is recognized by the existing Android OS and within the standard Android development environment this module can be used. Within this demonstrator it’s merely used to blink some LEDs and react to inputs, but it shows how to reuse one of these phones in a non-destructive manner. Even better is that the phone’s existing sensors and cameras can still be used as normal in this way, too, which opens a whole range of (cheap) DIY projects that can be programmed either in Java/Kotlin or in C or C++ via the Native Development Kit.

The only wrinkle is that while the phone is connected like this, charging is not possible. For the S4 it’s easy to solve as it has a removable battery, so an external power input was wired in with a dummy battery-sized bit of perfboard. With modern phones without removable batteries simultaneous USB/audio dongle and charging usage via the USB-C connector is claimed to be possible, but this is something to check beforehand.

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Building A Discrete 14-Bit String DAC

November 3, 2024 by Maya Posch 4 Comments

The discrete 14-bit DAC under test. (Credit: Sine Lab, YouTube)

How easy is it to build your own Digital to Analog Converter (DAC)? Although you can readily purchase a wide variety of DACs these days, building your own can be very instructive, as the [Sine Lab] on YouTube explores in a recent video with the construction of a discrete 14-bit DAC. First there are the different architectures you can pick for a DAC, which range from R-2R (resistor ladder) to delta-sigma versions, each having its own level of complexity and providing different response times, accuracy and other characteristics.

The architecture that the [Sine Lab] picked was a String DAC with interpolator. The String type DAC has the advantage of having inherently monotonic output voltage and better switching-induced glitch performance than the R-2R DAC. At its core it still uses resistors and switches (transistors), with the latter summing up the input digital value. This makes adding more bits to the DAC as easy as adding more of these same resistors and switches, the only question is how many. In the case of a String DAC that’d be 2^N, which implies that you want to use multiple strings, as in the above graphic.

Scaling this up to 16-bit would thus entail 65,536 resistors/switches in the naive approach, or with 2 8-bit strings 513 switches, 512 resistors and 2 buffers. In the actual design in the video both MOSFETs and 74HCT4051 multiplexers were used, which also necessitated creating two buses per string to help with the input decoding. This is the part where things get serious in the video, but the reasoning for each change and addition is explained clearly as the full 6-bit DAC with interpolator is being designed and built.

One big issue with discrete DACs comes when you have to find matching MOSFETs and similar, which is where LSI DACs are generally significantly more precise. Even so, this discrete design came pretty close to a commercial offering, which is pretty impressive.

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All You Need For Artificial Intelligence Is A Commodore 64

November 3, 2024 by Maya Posch 49 Comments

Artificial intelligence has always been around us, with [Timothy J. O’Malley]’s 1985 book on AI projects for the Commodore 64 being one example of this. With AI defined as being the theory and development of systems that can perform tasks that normally requiring human intelligence (e.g. visual perception, speech recognition, decision-making), this book is a good introduction to the many ways that computer systems for decades now have been able to learn, make decisions and in general become more human-like. Even if there’s no electronic personality behind the actions.

In the book’s first chapter, [Timothy] isn’t afraid to toss in some opinions about the true nature of intelligence and thinking. Starting with the concept that intelligence is based around storing information and being able to derive meaning from connections between stored pieces of information, the idea of a basic AI as one would use in a game for the computer opponent arises. A number of ways of implementing such an AI is explored in the first and subsequent chapters, using Towers of Hanoi, chess, Nim and other games.

After this we look at natural language processing – referencing ELIZA as an example – followed by heuristics, pattern recognition and AI for robotics. Although much of this may seem outdated in this modern age of LLMs and neural networks, it’s important to realize that much of what we consider ‘bleeding edge’ today has its roots in AI research performed in the 1950s and 1960s. As [Timothy] rightfully states in the final chapter, there is no real limit to how far you can push this type of AI as long as you have more hardware and storage to throw at the problem. This is where we now got datacenters full of GPU-equipped systems churning through vector space calculations for the sake of today’s LLM & diffusion model take on ‘AI’.

Using a Commodore 64 to demonstrate the (lack of) validity of claims is not a new one, with recently a group of researchers using one of these breadbin marvels to run an Ising model with a tensor network and outperforming IBM’s quantum processor. As they say, just because it’s new and shiny doesn’t necessarily mean that it is actually better.

Apple Forces The Signing Of Applications In MacOS Sequoia 15.1

November 1, 2024 by Maya Posch 134 Comments

The dialogue that greets you when you try to open an unsigned application in MacOS Sequoia 15.1.

Many MacOS users are probably used by now to the annoyance that comes with unsigned applications, as they require a few extra steps to launch them. This feature is called Gatekeeper and checks for an Apple Developer ID certificate. Starting with MacOS Sequoia 15, the easy bypassing of this feature with e.g. holding Control when clicking the application icon is now no longer an option, with version 15.1 disabling ways to bypass this completely. Not unsurprisingly, this change has caught especially users of open source software like OpenSCAD by surprise, as evidenced by a range of forum posts and GitHub tickets.

The issue of having to sign applications you run on MacOS has been a longstanding point of contention, with HomeBrew applications affected and the looming threat for applications sourced from elsewhere, with OpenSCAD issue ticket #880 from 2014 covering the saga for one OSS project. Now it would seem that to distribute MacOS software you need to have an Apple Developer Program membership, costing $99/year.

So far it appears that this forcing is deliberate on Apple’s side, with the FOSS community still sorting through possible workarounds and the full impact.

Thanks to [Robert Piston] for the tip.

KolibriOS: The Operating System That Fits On A 1.44 MB 3.5″ Floppy Disk

October 30, 2024 by Maya Posch 28 Comments

While most operating systems are written in C and C++, KolibriOS is written in pure x86 assembly and as a result small and lightweight enough to run off a standard 1.44 MB floppy disk, as demonstrated in a recent video by [Michael].

Screenshot of the KolibriOS desktop on first boot with default wallpaper.

As a fork of 32-bit MenuetOS back in 2004, KolibriOS has since followed its own course, sticking to the x86 codebase and requiring only a modest system with an i586-compatible CPU, 8 MB of RAM and VESA-compatible videocard. Unlike MenuetOS’ proprietary x86_64 version, there’s no 64-bit in KolibriOS, but at this level you probably won’t miss it.

In the video by [Michael], the OS boots incredibly fast off both a 3.5″ floppy and a CD-ROM, with the CD-ROM version having the advantage of more software being provided with it, including shareware versions of DOOM and Wolfenstein 3D.

Although web browsers (e.g. Netsurf) are also provided, [Michael] did not get Ethernet working, though he doesn’t say whether he checked the hardware compatibility list. Quite a few common 3Com, Intel and Realtek NICs are supported out of the box.

For audio it was a similar story, with the hardware compatibility left unverified after audio was found to be not working. Despite this, the OS was fast, stable, runs DOOM smoothly and overall seems to be a great small OS for x86 platforms that could give an old system a new lease on life.

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Tearing Down Nintendo’s Alarmo Alarm Clock

October 30, 2024 by Maya Posch 5 Comments

All your Nintendo Alarmo are belong to mew~ (Credit: GaryOderNichts, Blogspot)

Most of us will probably have seen Nintendo’s latest gadget pop up recently. Rather than a Switch 2 announcement, we got greeted with a Nintendo-branded alarm clock. Featuring a 2.8″ color LCD and a range of sensors, it can detect and respond to a user, and even work as an alarm clock for the low, low price of €99. All of which takes the form of Nintendo-themed characters alongside some mini-games. Naturally this has led people like [Gary] to buy one to see just how hackable these alarm clocks are.

As can be expected from a ‘smart’ alarm clock it has 2.4 GHz WiFi connectivity for firmware and content download, as well as a 24 GHz millimeter wave presence sensor. Before [Gary] even had received his Alarmo, others had already torn into their unit, uncovering the main MCU (STM32H730ZBI6) alongside a 4 GB eMMC IC, as well as the MCU’s SWD pads on the PCB. This gave [Gary] a quick start with reverse-engineering, though of course the MCU was protected (readout protection, or RDP) against firmware dumps, but the main firmware could be dumped from the eMMC without issues.

After this [Gary] had a heap of fun decrypting the firmware, which seems to always get loaded into the external octal SPI RAM before execution, as per the boot sequence (see featured image). This boot sequence offers a few possibilities for inserting one’s own (properly signed) contents. As it turns out via the USB route arbitrary firmware binaries can be loaded, which provided a backdoor to defeat RDP. Unfortunately the MCU is further locked down with Secure Access Mode, which prevents dumping the firmware again.

So far firmware updates for the Alarmo have not nailed shut the USB backdoor, making further reverse-engineering quite easy for the time being. If you too wish to hack your Alarmo and maybe add some feline charm, you can check [Gary]’s GitHub project.

Haiku OS’s Beta 5 Release Brings Us Into A New BeOS Era

October 30, 2024 by Maya Posch 26 Comments

The name BeOS is one which tends to evoke either sighs of nostalgia or blank stares, mostly determined by one’s knowledge of the 1990s operating system scene. Originally released in 1995 by Be Inc., it was featured primarily on the company’s PowerPC-based BeBox computers, as well as being pitched to potential customers including Apple, who was looking for a replacement for MacOS. By then running on both PowerPC and x86-based systems, BeOS remained one of those niche operating systems which even the free Personal Edition (PE) of BeOS Release 5 from 1998 could not change.

As one of the many who downloaded BeOS R5 PE and installed it on a Windows system to have a poke at it, I found it to be a visually charming and quite functional OS, but saw no urgent need to use it instead of Windows 98 SE or 2000. This would appear to have been the general response from the public, as no BeOS revival ensued. Yet even as BeOS floundered and Be Inc. got bought up, sold off and dissected for its parts, a group of fans who wanted to see BeOS live on decided to make their own version. First called OpenBeOS and now Haiku, it’s a fascinating look at a multimedia-centric desktop OS that feels both very 1990s, but also very modern.

With the recent release of the R1 Beta 5 much has been improved, which raises the interesting question of how close Haiku is to becoming a serious desktop OS contender.

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