Surviving Mars

Posted on Mon 11 April 2022 in games

I discovered another game that gives me an excuse to write silly calculator modules: Surviving Mars. Some random notes and a few tools I wrote, or interesting tools I found online:

Kerbal Space Program

Posted on Wed 25 August 2021 in games

I am usually late to proverbial parties, but I think I’ve outdone myself by discovering the computer game Kerbal Space Program roughly 10 years after it first became playable. It’s the kind of game that triggers my “I’ll optimize this by writing a script”, so here are …

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Monitoring network bandwidth of individual hosts from the router

Posted on Sat 28 November 2020 in monitoring

I live in a part of the world where broadband internet subscriptions come with a monthly data cap. The datacap is relatively large (750GB/month), but streaming 4k content will get you there! So I wanted to keep taps on my data usage. My router is the ideal place to …

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Cumulative graphs in Prometheus

Posted on Sun 16 August 2020 in monitoring

I've been experimenting a bit with Prometheus and Grafana. It allows you to make beautiful graphs from the metric data using relatively simple expressions. But one of the graphs that I had in mind, turned out to be more difficult. These are my notes.

I have a metric that counts …

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Half-duplex UART (RS485) on ESP32

Posted on Sun 26 April 2020 in microcontroller

I'm a happy owner of a few ESP32 microcontrollers. These are similar to the Arduino, but have WiFi & Bluetooth built in, which makes them very versatile. These chips come with a lot of peripherals, including three UARTs. These allow offloading the actual bit-banging of the pins to dedicated hardware …

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Raspberry pi 4 as broadband router

Posted on Fri 21 February 2020 in linux

A few years ago, I already considered using a Raspberry Pi as a broadband router. Back then, its first generation wasn't fast enough. This changed with the 4th generation of the Raspberry pi.

The test setup was similar to the setup I use previously:

  • Two beefy laptops on the ends …

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Reading CPU temperature and Fan speeds from the command line in macOs 10.14 Mojave

Posted on Fri 27 September 2019 in macOs

I was looking to read out the current temperature and fan speed of my MacBook Pro running macOS 10.14 Mojave. I prefered build-in tools over shady apps. After some searching, I found the powermetrics tool (which needs sudo privileges). By default, it outputs lots of details every 5 seconds …

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404to302 Lambda@Edge

Posted on Sun 22 September 2019 in misc

I discovered the 404to302 concept after a tweet by Aral Balkan, and immediately liked the idea. It solves a hard problem (keeping permalinks alive and working) in a fairly easy way: simply archive the old site, and avoid re-using the same permalink again. If you permalinks contain a date of …

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Switching to a static website

Posted on Sat 21 September 2019 in misc

After over 12 years of using WordPress, I switched to a static site generator. Here's the long story.

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Receiving NOAA images with RTL-SDR

Posted on Sun 25 August 2019 in sdr

During summer brake, I set out for a tech adventure together with my son. We wanted to do weather predictions ourselves. Or at least pretend to do so.

What sparked the idea, was a beautiful tweet from Receiving GOES satellites was a bit of a high bar for …

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