Sven Krasser's Blog

With many businesses and locations still shut down, projects at home are a good way to keep busy. While most of the posts on this blog revolve around electronics, information security, and machine learning (or on rare occasions rocket launch pictures), my most recent endeavor is in a new area: sewing. Specifically, sewing pajama pants, which as I understand it is to sewing what “Hello World” is to programming. If you enjoy the other topics on this blog, then maybe consider giving sewing a shot—it’s actually quite fun seeing something wearable coming together (and wearing it, of course).

Similar to my breadboard computer, the Commander X16 is an 8-bit computer based on a 6502 CPU, yet at a bit more professional level. The X16 team is working on actual hardware to be sold and shipped, but an emulator is already available on Github for everyone to try out the system. To give it a spin, I ported my rotozoom program from my breadboard computer to the emulated X16.

The latest addition to my homebrew 6502 computer is more colorful graphics output. To be specific, the system now supports output in 256 colors. As a little exercise, I’ve implemented a rotozoom effect to put the system through its paces. In this post, I’ll cover the hardware, the effect, and the implementation. Before getting into the details, you can find a YouTube video below showing the system in action. You can view the effect about one minute into the video.

In this second part on outputting a VGA signal from my homebrew 6502 breadboard computer, we’ll take a look at getting some motion onto the screen. If you missed the first part, you can catch up on the progress so far here.

After an 18-month hiatus, I continued work on my homebrew 6502 computer by adding VGA output so that programs can now generate some interesting graphics instead of just turning LEDs on and off.

In February, before the current Coronavirus outbreak hit the U.S. in earnest, I met up with Dave Cole in Marina del Rey to join as guest on an episode of the Security Voices podcast, hosted by Dave and his partner in crime Jack Daniel.

For my latest electronics project, I’ve built a small USB keyboard input device for media control. The final version has three keys: play/pause, previous track, and next track. In addition, a rotary encoder allows adjusting the volume (or mutes sound when pressed). This is also my first project involving a custom circuit board — my previous electronics projects mainly involved breadboards of varying sizes.

In my last post, I wrote about my first steps towards a 6502-based homebrew 8-bit computer. Since then I’ve added a 6522 Versatile Interface Adapter (VIA). More specifically, it is a W65C22S. The VIA has a number of functionalities (after all, it makes a claim to being versatile).

After completing my VGA Generator project a while back, I’ve embarked on a new electronics project: building a simple 6502-based homebrew 8-bit computer on a breadboard. There are a bunch of similar projects online from which to draw ideas. Some projects set constraints such as only using contemporary parts of the 8-bit era, no FPGAs, no microcontrollers etc. In my case, I opted instead to keep the constraints minimal and the project simple.

This past Monday morning, the OA-9 mission launched from Wallops Island to deliver supplies to the ISS. I was lucky to be able to watch the launch from the launch facility’s viewing area alongside the JPL RainCube team whose spacecraft was onboard the rocket.