Impressive 6502 Home Computer

Dirk Grappendorf has been working on a serious looking MOS 6502 based computer. Over at his site, you can follow his development diary.


The computer was developed between September 2014 and January 2015. Quite impressive, given the outcome! The entire design is available from Dirk’s git repository over at github.

Starting with the exterior, the machine lives in a 3D printed case (love the orange!). The keyboard has been salvaged, but the original circuitry has been replaced. This is a computer resembling the C64 and similar, but with Windows keys :-)


Looking into the hardware, the machine even contains a proper SID chip for that classic chip tune sound.

The finish of the hardware and case are impressive. So is the software. It includes everything expected from a mid-80’s home computer, including a BASIC interpreter. It is also possible to develop using C or assembler.

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Raspberry Pi as an Amiga Floppy Drive

As you probably know, the combination of retro computing and tinkering with embedded platforms tickles the mind of us here at DigitalFanatics. Someone who really hit that spot is Maurizio Ramondo and his Amiga Drive project.

Basically, it is about using a RaspberryPi as an Amiga floppy drive emulator. All the schematics and software are available for free. The schematics are for Eagle.

Amiga RPI Drive Design

The system consists of two parts – an interface board, letting the Raspberry Pi speak to the Amiga via the Floppy connector, and the Raspberry Pi software, emulating two Amiga floppy drives. The result is a system that can hold two disks at a time, but it also sports a change button, allowing you to switch to two new disks. This lets you play large games such as Monkey Island (four floppies, 720kB each, so almost 3MB).

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x86 timeline

Computer World has a nice timeline of the x86 processor family.

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FreeRTOS 8.2.0 Released

freertosVersion 8.2.0 of FreeRTOS, the open source, embedded RTOS has been released. The changelog reveals all the details. Some of the details are:

  • The new task notification feature, providing a fast, lightweight mechanism for inter-process exchange of limited data.
  • Following the trend of increased system resources, more inlining is used. This increases performance at the cost of space.

In addition to kernel updates and fixes, the demos have been updated.

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Emulator Preventing Tricks

One application of reverse engineering is the creation of emulators of old systems. This is often done to preserve the technology and to address the lack of access to functioning hardware.

One such system is the Game Boy Advance. Produced between 2001 and 2008, it is a fairly recent system. It is Arm based, has a farily small screen, a Z80 coprocessor and a relatively small RAM (256kB + 32kB + 96kB). From an I/O perspective, it is a fairly limited system, which helps. However, the cartridge system means that games are not only a piece of ROM, but can contain more functionality.

The mGBA emulator team recently posted a blog post on some of the tricks used by game vendors (in this particular case, Nintendo themselves) to prevent emulators from working. An interesting read, both from a hardware and software perspective.

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Debug witout printf

The use of printf for debugging purposes is sometimes regarded as bad practice. However, sometimes even that is a luxury. Mark Seaborn has written a piece on this.

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KeySweeper – Sweeping away Microsoft keyboards

Samy Kamkar has an interesting post on the security implementation in the Microsoft wireless keyboard. Using some smart heuristics, the scanning period to find and get access to the key presses of a wireless Microsoft keyboard is only 40s.


In addition to discussing the protocol and how to break the security of it, he demonstrates a build of a sniffer hidden inside a USB charging device – the KeySweeper. Leave it in range of the keyboard and wait. The cost of all this? 10 – 80USD, depending on how advanced you want to make it.

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Reverser Engineering an IR Protocol

Reverse engineering is always an interesting technical challenge. Vincent and Mathieu from France used the AnalysIR equipment. This challenge was not only about understanding the protocols, but learning to generate checksums and how the various frames relate to each other.


The AnalysIR team has published a nice summary of the findings, and the details can be found on github.


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Quick and Dirty Charger

Here is a quick and dirty article telling you about a quick and dirty solar charger from It is a nice, simplistic hack to create a USB solar charger.


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Amazing Clock

Taking dead bug style electronics construction to new heights, The Clock project is a piece of art appreciable not only by engineers.


The project is the creation of Gislain Benoit and took three years to design. He describes the project as this.

…it has been hand crafted. The thousands of parts that compose it are soldered together in a 3-dimensional structure. There is no electronic board involved. The parts are linked to hold themselves and reveal the complexity of the circuit through the solid wiring that keeps them together which gives a visually astonishing result. The symmetry and density of its parts and interconnections has been kept uniform throughout the circuit. Every single part that composes the clock has its purpose. If you would decide to take out a single part of the circuit the clock won’t operate properly anymore.

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