generative art: flowers

It started with this tweet about someone called Ayliean apparently drawing a plant based upon set rules and rolling a dice.

And because generative art in itself is fascinating I am frequently pulled into such things. Like this dungeon generator or these city maps or generated audio or face generators or buildings and patterns

On the topic of flowers there’s another actual implementation of the above mentioned concept available:

TubeTime and BitSavers

I was pointing to BitSavers before. And I will do it again as it’s a never ending source of joy.

Now some old schematics had been spilled into my feeds that show how logic gates had been implemented with transformers only.

BitSaver brought it up:

And not only BitSaver is on this path of sharing knowledge, also TubeTime is such a nice account to follow and read.

batch convert HEIF/HEIC pictures

When you own a recent iOS device (iOS 11 and up) you’ve got the choice between “High Efficiency” or “Most Compatible” as the format all pictures are being stored by the camera app.

Most Compatible being the JPEG format that is widely used around the internet and other cameras out there and the “High Efficiency” coming from the introduction of a new file format and compression/reduction algorithms.

A pointer to more information about the format:

High Efficiency Image File Format (HEIF), also known as High Efficiency Image Coding (HEIC), is a file format for individual images and image sequences. It was developed by the Moving Picture Experts Group (MPEG) and is defined by MPEG-H Part 12 (ISO/IEC 23008-12). The MPEG group claims that twice as much information can be stored in a HEIF image as in a JPEG image of the same size, resulting in a better quality image. HEIF also supports animation, and is capable of storing more information than an animated GIF at a small fraction of the size.

Wikipedia: HEIF

As Apple is aware this new format is not compatible with any existing tool chain to work with pictures from cameras. So you would either need new, upgraded tools (the Apple-way) or you would need to convert your images to the “older” – not-so-efficient JPEG format.

To my surprise it’s not trivial to find a conversion tool. For Linux I’ve already wrote about such a tool here.

For macOS and Windows, look no further. Waltr2 is an app catering your conversion needs with a drag-and-drop interface.

It’s advertised as being free and offline. And it works a treat for me.

a proper 7-segment / 14-segment font

DSEG is a free font family, which imitate seven and fourteen segment display(7SEG,14SEG). DSEG have special features:

  • DSEG includes the roman-alphabet and symbol glyphs.
  • More than 50 types are available.
  • True type font(*.ttf) and Web Open Type File Format (*.woff, *.woff2) are in a package.
  • DSEG is licensed under the SIL Open Font License 1.1.

Get it here.

Reminder: addition of floating point numbers is NOT associative

Reminder: addition of floating point numbers is NOT associative… (0.1 + 0.2) + 0.3 ≠ 0.1 + (0.2 + 0.3) …and this is true in basically _any_ language that uses floating point numbers. Here it is in javascript in the browser console:

Mark Kriegsman on Twitter

dangerously curious bitcoins

Some things you find on GitHub are more interesting and frightening than others.

This one is both and some more. What is it you ask?

R2 Bitcoin Arbitrager is an automatic arbitrage trading application targeting Bitcoin exchanges.

So it’s buying and selling Bitcoins. And it’s doing this on different markets.
On the topic of arbitrage Wikipedia has something to say:

In economics and finance, arbitrage is the practice of taking advantage of a price difference between two or more markets: striking a combination of matching deals that capitalize upon the imbalance, the profit being the difference between the market prices at which the unit is traded.

For example, an arbitrage opportunity is present when there is the opportunity to instantaneously buy something for a low price and sell it for a higher price.

https://en.wikipedia.org/wiki/Arbitrage

Now this already is the second version of the tool and already 2 years old. See it as some sort of interesting archeological specimem. Please refrain to actually so something harmful with it.

I am writing this down here because apart from it’s obvious horrors this is a good starting point to understand how these computer-trading-systems do work in principle.

Given that an architectural drawing is also included it gives all sorts of starting points to thoughts.

Also. What could possibly go wrong if a tool to buy/sell on actual markets with actual bitcoins is confident enough to include the “maxTargetProfit” configuration option. Effectively setting the top-line of profit you’re going to make!!!111

Linux mac80211 compatible full-stack Wi-Fi design based on SDR

In a tweet we were given an early christmas present – open-sdr released an open source software Wi-Fi stack that utilizes software-defined-radio technology to implement actual working Wi-Fi.

Features:

  • 802.11a/g; 802.11n MCS 0~7; 20MHz
  • Mode tested: Ad-hoc; Station; AP
  • DCF (CSMA/CA) low MAC layer in FPGA
  • Configurable channel access priority parameters:
    • duration of RTS/CTS, CTS-to-self
    • SIFS/DIFS/xIFS/slot-time/CW/etc
  • Time slicing based on MAC address
  • Easy to change bandwidth and frequency:
    • 2MHz for 802.11ah in sub-GHz
    • 10MHz for 802.11p/vehicle in 5.9GHz
  • On roadmap: 802.11ax

See this demonstration:

Drag and drop ML with transparency

The machine-learning tooling is getting better. Take a look at Perceptilabs:

Fast modeling
With our drag and drop GUI we enable fast model development.

Increased transparency
The statistical dashboard increases the model’s transparency during training.
Get a better understanding of your model with instant feedback on the operations outputs.
We enable fast error debugging with our custom code editor.

Flexibility
Full flexible options for plugins and importing. Execute any custom Python code in our code editor.

Tabemono – from a name to UX and UI…

As you might know by now I am re-implementing MyFitnessPal functionality into my own application to be deeper integrated with kitchen hardware and my own personal use-cases rather than to be an add infested subscription based 3rd party applilcation.

So the development of this is ongoing, but I wanted to note down some progress and explanation.

Let’s start with explaining the name: Tabemono.

It does really mean something – and as some might have guessed – in japanese:

Tabemono – 食べ物

Taking just the first Kanji:

Implementing the UI from the UX has proven to be as challenging as expected.

When we started to toss around the idea of re-implementing our food-tracking-needs we started with a simple scribble on post-it notes.

This quickly led to a digital version of this to better reflect what we wanted to happen during the different steps of use…

It wasn’t nice but it did act as an reminder of what we wanted to achieve.

The first thing we learned here was that this will all evolve while we are working on it.

So during a long international flight I’ve spent the better part of 11 hours on getting the above drawing into something resembling an iOS user interface mock-up. With the help of the (free for 1 private project) Adobe XD I clicked along and after 10 hours, this was the video I did of the click-dummy:

Since then I’ve spend maybe 1 more day and started the SwiftUI based implementation of the actual iOS application.

And this brought the first revelation: There are so many ideas that might make sense on paper and in a click-dummy. But only because those are just tools and not reality. It’s absolutely crucial to really DO the things rather than imagine them.

And so the second revelation came: If I had an advise to any product manager or developer out there: Go on and pick a project and try to go full-circle.

You ain’t full stack if you’re missing out on the understanding of the work and skill that your team members have and need.

OpenFood Facts

Open Food Facts gathers information and data on food products from around the world.

To replace MyFitnessPal in our toolchain I am on the hunt for at least some quality food fact data.

The Open Food Facts data base seems to be one source – although in sparse and questionable quality (after first initial testing).

There is a comprehensive documentation about the fields of data supported. And there are several formats that the raw data can be downloaded in.

There are ready-made applications available as well. Definitly worth looking into further.

smart OpenVPN client for iOS

There is a free and well integrated OpenVPN client for iOS devices already. And as much as this one works quite well it’s also lacking some comfort features that are now made available through alternative iOS client implementations of OpenVPN.

OpenVPN is an open-source commercial software that implements virtual private network techniques to create secure point-to-point or site-to-site connections in routed or bridged configurations and remote access facilities. It uses a custom security protocol that utilizes SSL/TLS for key exchange.

https://en.wikipedia.org/wiki/OpenVPN

Meet Passepartout. The iOS OpenVPN client that comes with lots of comfort features. Of main interest for me is that Passepartout is aware of the connection you’re currently using and can adopt it’s VPN tunnel status accordingly.

Passepartout is a smart OpenVPN client perfectly integrated with the iOS platform. Passepartout is the only app you need for both well-known OpenVPN providers and your personal OpenVPN servers.

collection of pure bash alternatives to external processes

The goal of this book is to document commonly-known and lesser-known methods of doing various tasks using only built-in bash features. Using the snippets from this bible can help remove unneeded dependencies from scripts and in most cases make them faster. I came across these tips and discovered a few while developing neofetchpxltrm and other smaller projects.

https://github.com/dylanaraps/pure-bash-bible

eXoDOS

eXoDOS is an attempt to catalog, obtain, and make playable every game developed for the DOS and PC Booter platform. Striving to find original media rather than using scene rips. This collection uses a combination of Dosbox and ScummVM to play these older titles on modern systems. All required emulators are included and have been setup to run all included titles with no prior knowledge or experience required on the users part.

This pack includes 7,000 DOS games. The focus is on games that were either released in English or are fairly easy to play without a knowledge of the native language. This is not every DOS game ever made, however it is a very high percentage of all commercial releases. There are thousands of freeware, homebrew, and shareware games that will continue to be added in future packs.

The games have already been configured to run in DosBOX. Games which are supported by ScummVM will give you the option at launch as to which emulator you would like to use.

https://exodos.the-eye.eu/

the big list of RTL-SDR supported software

RTL-SDR is a very cheap ~$25 USB dongle that can be used as a computer based radio scanner for receiving live radio signals in your area (no internet required). Depending on the particular model it could receive frequencies from 500 kHz up to 1.75 GHz. Most software for the RTL-SDR is also community developed, and provided free of charge.

The origins of RTL-SDR stem from mass produced DVB-T TV tuner dongles that were based on the RTL2832U chipset. With the combined efforts of Antti Palosaari, Eric Fry and Osmocom (in particular Steve Markgraf) it was found that the raw I/Q data on the RTL2832U chipset could be accessed directly, which allowed the DVB-T TV tuner to be converted into a wideband software defined radio via a custom software driver developed by Steve Markgraf. If you’ve ever enjoyed the RTL-SDR project please consider donating to Osmocom via Open Collective as they are the ones who developed the drivers and brought RTL-SDR to life.

https://www.rtl-sdr.com/about-rtl-sdr/

And since the hardware is so affordable there’s lots of software and therefore things that can be done with it.

Shepard’s Pi

“Shepard’s Pi” is one continous song that lasts for 999,999,999 hours, or about 114 years.

Canton Becker’s music generating algorithm composed this music using the first one billion digits of pi (p). Each digit (3.1415…) determines four seconds of music, supplying the “turn signals” used to determine every musical expression.

Because the numbers in pi never repeat, each of the million hours of “Shepard’s Pi” music are in fact unique. By fast forwarding to some distant moment in the song, you are virtually guaranteed to find yourself listening to something that nobody else – including Canton himself – has ever heard before.

Shepard’s Pi

Streamsheets

Streamsheets is, similar to NodeRed, a tool to step in between MQTT data coming in and something being done with it. Just other than NodeRed it is not based on flows but on a spreadsheet that executes in it’s entirety everytime a step is made.

Streamsheets are a new spreadsheet technology specifically designed for real-time data stream processing and the opportunities of digitization and the Industrial IoT.

Streamsheets

SwiftUI on the Web

SwiftUI is the new cool kid on the block when it comes to iOS/iPadOS/macOS application development.

As Apple announced SwiftUI early 2019 it’s naturally only focussing on making all the declarative UI goodness available for the Apple operating systems. No non-apple platforms in focus. Naturally.

But there are ways. With the declarative way of creating user interfaces one apparently can simply start to re-implement the UI controls and have them render as HTML / Javascript…

The SwiftWebUI project is aiming to do so:

Unlike some other efforts this doesn’t just render SwiftUI Views as HTML. It also sets up a connection between the browser and the code hosted in the Swift server, allowing for interaction – buttons, pickers, steppers, lists, navigation, you get it all!

In other words: SwiftWebUI is an implementation of (many but not all parts of) the SwiftUI API for the browser.

To repeat the Disclaimer: This is a toy project! Do not use for production. Use it to learn more about SwiftUI and its inner workings.

SwiftWebUI

Making a RISC-V operating system using Rust

As RISC-V progressively challenges the existing ARM processor ecosystem it’s interesting to see more and more software projects popping up that aim that RISC-V architecture.

Here’s one project that aims to develop (and explain along the way) how to create an operating system from scratch. On top of the RISC-V specifics this tutorial also aims to teach how this all can be done in a programming language called Rust.

Keep in mind that all of this is done on a baremetal system. No other software is running.

RISC-V (“risk five”) and the Rust programming language both start with an R, so naturally they fit together. In this blog, we will write an operating system targeting the RISC-V architecture in Rust (mostly). If you have a sane development environment for RISC-V, you can skip the setup parts right to bootloading. Otherwise, it’ll be fairly difficult to get started.

This tutorial will progressively build an operating system from start to something that you can show your friends or parents — if they’re significantly young enough. Since I’m rather new at this I decided to make it a “feature” that each blog post will mature as time goes on. More details will be added and some will be clarified. I look forward to hearing from you!

The Adventures of OS

a 1980s style computer built today for fun

Can you display VGA and play audio on a Cortex-M4 in pure Rust? The short answer is yes, yes you can! Minus the hand-unrolled assembler loop for fixing the phase error in the RGB output. But we don’t talk about that in polite company.

Monotron project page

What currently is in place:

  • The Atari Joystick interface works, but two Joysticks would be more fun
  • The PS/2 Keyboard via the Atmega works, but the pinout was mirrored so you have to put the connector under the PCB :/
  • The RTC works
  • VGA Output works
  • The MIDI Out seems to work when looped to MIDI In, as does the MIDI Though.
  • The MIDI In seems to receive data when connected to my electronic drum kit
  • The Audio output seems to work quite nicely
  • The SD card works, but the power supply can’t handle hot-insertion of the SD card and it makes the TM4C reboot. More capacitors / some current limiting probably required.

I can load games and programs from the SD card into the 24 KiB of free Application RAM. You can interact with these games via the PS/2 Keyboard and Joystick. I can play simple games (like Snake) and play three channels of 8-bit wavetable audio simultaneously. I’ve even got a 6502 Emulator running a copy of 6502 Enhanced BASIC, if you want to go old school!

Localino – Indoor Location

As you might know I am regularly looking into indoor-location systems and opportunities to optimize my own system (based on Bluetooth…)

Now I cam across a concept by a german company called Localino. They’ve built their own hard- and software.

Localino has its own “satellites”, also called “anchors”. The mobile receivers are called “tags” and can locate their position based on the available anchors inside a building. Anchors and tags precisely measure signal propagation delays in the order of sub-nanoseconds, resulting in centimeter-accurate location. Any person or object wearing a tag can be located.

Localino website

There’s also a hack-a-day article on the system which states that all hard- and software would be open source. So far I did not find any source code though…

As far as I could dig into this so far it’s based upon decawave DW1000 hardware and an older base-library of this is available as source code here.

There are some other mentions which are back from 2017 when there seemingly was a big open source portion. Some python code is mentioned but nothing available right away today sadly.

REST-API testing: Reqres

I am back again and developing some smaller APIs for my own use.

As I am learning a new programming language and framework (SwiftUI) and for my little learning project I need to also implement a server backend. Implementing a RESTful service is quite straight-forward but for testing and UI prototyping I actually want to do some testing before really setting up the server side.

To easily test RESTful calls without actually implementing anything I found that Reqres is a quite useful tool to have in the toolbelt:

Apart from some pre-set-up API endpoints with dummy data (like users, …) it also features a request mirror service.

With that you can simply throw a JSON document into the general direction of Reqres and it will put a timestamp on it and return it right away.

Like so:

Writing Network Drivers in C#

Somebody had to do it. Maximilian Stadlmeier did:

User space network drivers on Linux are often used in production environments to improve the performance of network-heavy applications. However, their inner workings are not clear to most
programmers who use them. ixy aims to change this by providing a small educational user space network driver, which is gives a good overview of how these drivers work, using only 1000 lines of C code.
While the language C is a good common denominator, which many developers are familiar with, its syntax is often much more dicult to read than that of more modern languages and makes the driver seem more complex than it actually is.

For this thesis I created a C# version of ixy, named ixy.cs, which utilizes the more modern syntax and additional safety of the C# programming language in order to make user space network driver development even more accessible. The viability of C# for driver programming will be analyzed and its advantages and disadvantages will be discussed.

The actual implementation (with other programming languages as well) can be found here.

Apparently it’s not as slow as you might think:

Odometer for the HUD

Since I am back at developing the Head-Up-Display app I was writing about in February (yeah, mornings got darker again!) I want to leave this nice looking Odometer Javascript library here:

Odometer is a Javascript and CSS library for smoothly transitioning numbers. See the demo page for some examples.

Odometer’s animations are handled entirely in CSS using transforms making them extremely performant, with automatic fallback on older browsers.

odometer

Bulletin Board Systems in the wild

While recording a podcast episode we briefly touched on the topic of bulletin board systems and how we both had operated our own FidoNet BBS in the 90s.

To create a bigger reflux of thoughts:

Synchronet Bulletin Board System Software is a free software package that can turn your personal computer into your own custom online service supporting multiple simultaneous users with hierarchical message and file areas, multi-user chat, and the ever-popular BBS door games.

Everything there to set-up a BBS. Maybe I really need to get out a backup of my old BBS and bring it back online?!

TIL: iPhone Visual Voicemal is IMAP

Today I learned that the Apple iPhone re-purposes the IMAP protocol to implement the voice mail feature.

By sniffing the network traffic it was possible to examine the IMAP protocol revealing username and the corresponding hashed password (which allows to repeat a successful login) and of course all voicemail files. We want to highlight, that all the voicemail files have been transferred unencrypted.

Assessment of Visual Voicemail from 2012