Hello World!

Hello dear reader, hello search engine crawler, hello XKeyscore! This will now be my personal blog – I will be writing about my software and DIY projects I build from time to time. Also I will use this blog to write about just anything I find worth publishing – still with a focus on technology (probably). The name CHRZ was literally chosen… Read More →

Postcards From the ISS

Sometimes, the folks over at the International Space Station (ISS) send greetings to earth, postcards encoded as SSTV images – transmitted at 145.800 MHz FM. Of course, I wanted to receive some. And in April 2018, I managed to. Hardware and Software I used the same hardware receiving stack as I used for receiving NOAA and Meteor weather satellites. In… Read More →

Receiving Meteor LRPT Weather Maps

After much success receiving weather maps from the NOAA satellites, I wanted to receive more satellites. While the NOAA satellites are US-based and are relatively old, the METEOR-M2 are of a more recent make, operated by Russia. However, the LRPT signals sent by the Meteor satellites are digital and somewhat harder to decode. But thanks to some ambitious russian friends,… Read More →

Receiving NOAA APT Weather Maps

After building a satellite antenna, I was able to receive and decode the weather maps sent by three US-based legacy satellites operated by the National Oceanic and Atmospheric Administration (NOAA). Hardware As mentioned, I used my own antenna. To get the signal into my PC, I used the excellent and low-cost RTL-SDR stick V3 by RTL-SDR.com. My base station consisted… Read More →

Building a Weather Satellite Antenna

During my adventures with SDR (software-defined radio), the need for a proper QFH antenna arose. This type of antenna is used to receive signals that are circularly polarized, such as APT weather maps sent by the NOAA satellites. I used a PVC pipe and a standard shielded coax cable from the local hardware store, and a copper tube meant for… Read More →

Building a Laser Cutter: Part 4 – Tests and Stability Improvements

The laser cutter is finally ready for testing! After securing the aluminium base plate (before that I had used carton) I powered up the system and sent my first gcode. Improving the Y Carriage Unfortunately, the lasered lines were rather wobbly. This was because the y carriage was only supported by one shaft. So, I ordered more parts. From Steplab:… Read More →

The Beer Crate Boombox

A few years ago, in 2017, I attended a rather large music festival. Apart from the music and general camping experience, one thing particularly got stuck in my mind: Someone wearing a beer crate as a backpack. While one could argue this not being an unusual sight at a music festival, the thing that impressed me as a maker were… Read More →

Building a Laser Cutter: Part 3 – Electronics and Control

After completing the machnical construction of the laser cutter, it was time for the control circuit. I used a perfboard PSB and soldered headers for the Arduino and stepper motor drivers to it. On the bottom, I connected everything up. The limit switches needed some simple debouncing and smoothing on their signals, because the cables were so long and the… Read More →

Building a Laser Cutter: Part 2 – Mechanical Build

After designing my laser cutter, the next step was to order the parts and assemble the machine. Because Actobotics parts are made and sold from USA, they are hard to come by in Europe (unless you want to pay high import taxes and shipping). In the end, I found an Italian shop (steplab.net / servocity.eu) which sold pretty much everything… Read More →

Building a Laser Cutter: Part 1 – Idea and Plan

In 2016, I built a CNC laser cutter / engraver. I always wanted to document the whole process, but never got around to do so – until now. Enjoy a multi-part series on how my build went! Before I start, a word of warning: Lasers can be very dangerous to your health, eyes and general envoirement if misused. Please make… Read More →