Sven Krasser's Blog
Musings on technology, security & sundries
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First Impressions of the Tokina SZX 400mm f/8
Nikon’s lens lineup for the Z-mount is still fairly sparse at the telephoto end of the spectrum (as I noted e.g. in my post on the Sentinel-6 launch). I was hoping for the 100-400mm being released soon by Nikon, but so far there hasn’t been much movement on lenses with long focal lengths outside of the 70-200mm and the 24-200mm. To fill up my camera bag in the interim with some longer lenses, I decided to give the Tokina SZX 400mm f/8 a try now that it comes as a Z-mount version.

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Upgrading a Creality CR-X Pro with an E3D Chimera+ Hotend
What follows has been a bit of an odd project to me. My 3D printer so far has been a Flashforge Creator Pro (you can see it in action on my YouTube channel), and it generally “just works.” The thought of modding a 3D printer was as remote to me as messing with the innards of my (paper) laser printer. That changed when my friend Marcus approached me to find a new home for his second printer, the aforementioned CR-X Pro (specifically, an upgraded version sold by TinyMachines3D). The printer has an appealingly large print volume, but the catch was that it no longer had a hotend. However, Marcus had a new dual-nozzle E3D Chimera hotend already at hand, along with a bunch of crimped extension cables. So with a bunch of goodies stashed in my hallway, I set out to solve this electromechanical puzzle. If you’re already familiar with messing with your printer, this post will contain a bunch of obvious facts, quite possibly some solutions contrary to best practices, and maybe a couple of chuckles as I work through the project by trial and error. Lots of error. But if you’re a casual 3D-printing enthusiast, there are hopefully a few useful pieces of information in here, too.

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Joshua Tree National Park
This month, my wife, our beagle, and I spent a week in Joshua Tree. Here are a couple of photos from the National Park and the area.
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C64 Build Video
I’ve posted a new video on my YouTube channel covering my earlier posts on building a C64 using an Ultimate 64 board and 3D-printing a joystick and paddle controller. While this utilizes a bunch of old footage and pictures from earlier last year, it also gave me an opportunity to use my new camera and some new backdrops I got (for example, for this shot of the components for the paddle controller). You can view the video below.
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6502 Scripting: a Tcl Shell on the Commodore 64
The C64’s user interface is Commodore BASIC v2, which presents itself without delay as a REPL the instant the machine is powered on. BASIC lives in 8 KB of ROM of 6502 machine code. Michael Steil has worked on collecting versions of the BASIC source for various 8-bit platforms, putting them into a single source tree, and adding comments. There’s also EhBASIC by Lee Davidson, a popular BASIC interpreter used by a number of 6502-based homebrew computers. EhBASIC fits into 10 KB.
There were other interpreted languages available for the C64, e.g. LISP dialects such as LISP 64 (page in German). From a glance at the screenshots, LISP 64 is delivered as a 52-block large PRG file, so about 13 KB in size.
With scripting on resource-deprived microcontrollers becoming more popular, I was wondering if there are also new options for 6502-based systems. Alas, languages like MicroPython still require at least hundreds of KB of memory for the interpreter. Then, I came across an excellent blog post by Serge Zaitsev who was evidently on a similar mission in 2016.