Christopher Getschmann
In mapmaking, one of the oldest problems is finding a visually pleasing way to represent elevation using just two dimensions (or as Edward Tufte would call it: trying to escape flatland).
Python is a great language and if you prioritize prototyping and getting results quickly (as I do with most of my projects) the trade-offs between programmer productivity and processing speed are fine for me. The really time-consuming parts are outsourced to numpy, OpenCV, or other “fast” libraries with compiled code, and the speed of my Python code (or lack thereof) is negligible. Ultimately, my…
For an art project I needed a lightweight way to trigger spray cans with a motor.
Ultra-long exposure images or Solargraphy are photos that are taken over the span of a few hours, days or weeks or months. Usually, they include the bright arcs the sun takes over the course of at least one sunny day. In the case of analog Solargraphy images, the exposure often lasts from solstice to solstice for half a year, showing all arcs from the lowest to the highest point of the sun in the…
Have you ever felt the need to make flexible and squishy lenses from silicone? Do you only have a 3d printer and a very basic CNC mill at home? Then you may be the target audience. What I’m writing about here only works for concave molds which make convex-convex or plano-convex lenses and I admit that whole thing is certainly something of a niche topic, but I mean, that’s what the internet is for.…
Recently I found myself on a yak shaving detour in dire need to look at some very small things. In my particular case: to assess scratches after consecutive grinding and polishing steps of a lens mold. Basically, I polished a cavity and needed to know if the scratches of the prior grind size have been removed by the current grain size so I can move on to the next one. For that, I needed some cheap…
It’s silly. It’s slightly impractical. It’s a toy camera. More about that here .
Just as an afterthought to the Geodesic Light: The Lighthouse Lamp
I felt like making a stupid lamp and that’s how it looks like. More about it here: /thing/geodesiclight
Recently I spent a bit of time thinking about visually improving non-functional areas of a 3d-printed part. Some generated pattern which could be imprinted on some parts of the object while not creating any issues with geometries that are required for functionality and still being (somewhat) printable. Disclaimer: I started this inquiry with very little knowledge about 3d stuff (point clouds,…
Sometimes it’s not possible or really tedious to get a USB cable to the USB connector for power input on a Raspberry Pi. Since the 5V pins, the USB power connector, and the USB hub share the same power rail, it doesn’t matter where the electrons enter and exit. The only difference is that the Pi has a few capacitors, a resettable fuse, and a diode directly behind the USB input. When powering the…
I have a soft spot in my heart for really weird contraptions to take pictures. A non-exhaustive list of at least slightly unusual cameras which may get updated from time to time…
Finally managed to do a video on digital solargraphy and explain the concept a bit more visually. gif / webm / mp4 gif / webm / mp4 gif / webm / mp4 gif / webm / mp4 gif / webm / mp4
Sometimes one may require a non-planar mirror. Usually you can do that by turning and polishing a chunk of metal on a lathe until it is so smooth that the metal works like a mirror. Or you can achieve a mirror surface by grinding a piece of glass or coating plastic in a vacuum chamber. All of that is pretty slow and expensive. But is there maybe an easier or faster way at the cost of a bit of…
When building prototypes that require tiny projectors capable of projecting an okay-ish image over short to mid-sized distances, finding something decent is not easy. In my case I needed something that is as small as possible, has a wide field of view and should ideally be compatible with a small Raspberry Pi Zero.
Sometimes one just needs a custom flat flex cable. In my case this was a Raspberry Pi Zero camera cable. A quick search told me that flex PCBs have fancy stuff like polyamide stiffeners to make certain parts more … stiff (obviously). This increases the PCBs thickness slightly so connectors are chosen to accomodate that. Flex PCBs are apparently really expensive. Not so much the per-unit price but…
For quite some time I entertained the thought of having a wall-sized world map. Maybe it started when I read the blog post by Dominik Schwarz about his map, maybe a bit earlier. Exactly as Dominik I soon realized it’s really hard to buy a map which is neither ugly nor has a low resolution/amount of details. There are a few maps I enjoy visually and probably on the top of the list is the bathymetry…
Getting a neutral density filter on a fisheye is a horrible mess. Some fisheye lenses solve this in a sane manner by having an integrated filter mount somewhere in the lens barrel (usually in between some lens elements close to the camera, not the front). That’s about the worst possible solution for the problem. Some people use tape, glue or magnets to fit ND filter foils to the rear element of…
A few months ago the Raspberry Pi HQ camera module was released. 12MP resolution, 1/2 inch (8mm) sensor, all in all: sounds ok. The interesting thing: you can change the lenses. The mount is apparently called a CS-Mount and is simply a screw thread. (Modern) CS lenses however are mostly CCTV/surveillance camera lenses and that’s a rather suspicious market if you want to go shopping (lots of…
Update: a number of people got in contact with me after writing this blog post inquiring how exactly they can get or build their own camera. The hardware and software described below is not very compatible with people that are not exactly me. I did change a lot in the meantime and now I am quite confident that the whole thing is a bit easier to use. I did set up a page to describe how to get your…
Pedestrian movement data based on drone footage. 20min time snippets taken at 60-65m height.
For everyone who needs to run gphoto on a buildroot system and wants to save some time:
For various reasons it may be beneficial to be able to turn off or toggle an USB connection or a USB port.
To understand and quantify the usage of public places and plazas, I developed a tracking tool using smartphones as my Master’s Thesis.
I’ve built a medium-sized camera housing a while ago for a stationary multi-day/week installation. Version 2 of the outdoor camera housing is intended to be a little bit more portable.
For the Summaery 2016, the annual exhibition of the Bauhaus-University Weimar I made a long exposure project. The plan was to expose an image for about four days. In the end the camera failed and just managed to record 16 hours, but the part about the camera enclosure may be interesting.
Erinnerung für mich selbst, wenn mal wieder ein Raspberry Pi ans Uni-Netz angebunden werden muss:
finally online: my new project compressed time.
Es ist schwierig in Japan halbwegs günstig und komfortabel an Internet zu kommen, was natürlich auch daran liegen mag das meine Messlatte für 'komfortabel' recht hoch liegt. Die erste Hürde ist das "Prevention of Improper Use of Mobile Voice Communications Services Act" [*], ein Gesetz, das Verkauf von SIM-Karten an Ausländer und Touristen unter Geldstrafe verbietet. Wie es nunmal ist, haben sich…
Tokyo, Ikebukuro, erste Woche Sendai, zweite Woche Sendai, zweite Woche Tokyo, Shinjuku, dritte Woche Tokyo, Ikebukuro, dritte Woche Tokyo, Kawasaki, dritte Woche
Durchsichtige Regenschirme. Wunderbare Idee. Sieht bescheuert aus, aber macht die lästige Verwendung um so vieles angenehmer. Bezahlung im Restaurant am Automaten. Am Automaten vorm Restaurant wählt man Gericht, zahlt und zieht einen Zettel den man im Restaurant lediglich vorlegen muss um seine Suppe zu bekommen. Kurz irritierend, aber effizient. Warteblöcke zum Einsteigen. In Tokyo sind auf den…
Als Teil einer Vorlesung an der Bauhaus-Universität. Maschinelles Kategorisieren und Verorten von Polizeiberichten der Polizeidirektion Weimar, inklusive Visualisierung mit OpenStreetMap-Daten. Code: github
Since I somehow never finish what I start, I can publish it anyways: I don't want to get (all) my mail pushed to my phone but nonetheless I am using email for urgent matters. calcifer is a simple python daemon, reading your mail and sending you notifications of (important) mails via Pushover. Using native notifications via the Apple Push Notification Service wouldn't be hard, but Pushover is a…
More than a year ago I finished my bachelor thesis about wearable tactile displays. The aim was to assist visually impaired people in their mobile usage of a smartphone. Over the course of six month I developed a concept and a prototype for a tactile I/O device, embedded in a gauntlet-like piece of clothing. Notifications from the smartphone, encoded as Braille-characters, are displayed as…
War schön.
10 Tage, 600 Meilen, Hostels & Zelt
Medienhafen from volzotan on Vimeo.
I really like physical buttons. And well documented hardware, that comes with the option to tinker around. Novation Launchpads are MIDI-Controllers for live perfomances and electronic music stuff. 8x8 Buttons, 2 LEDs each and a simple MIDI communication interface. Novation released a short, but sufficient documentation about how to talk to your device and makes it very easy to use your hardware…
A few month ago I started running with the Zombies, Run! 5k Training app. The data from the app is synced with the webservice and online you can see a few graphs which are quite ok, but I wanted a bit more than that. You can download a GPX-File from every run, but there is no way to download an archive. So I scraped the logs from the "Zombies, Run!"-backend using their REST API. GPX parsing is…