- About me -

vladimir

Vladimir Zhelezarov

Currently (in my free time) working on:
  • Pursuing a Bachelor-Degree in "Digital Engineering and Applied Computer Science" at AKAD Stuttgart. Check github for some of my student work.

- Portfolio -

A low-tech error logging facility for the VCU*

Quick troubleshooting by VCU-errors.

  • The centrifugal switches are connected in series, which is often problematic when troubleshooting. In almost all cases, the problem is a loose connection, which sporadically works.
  • I suggest a simple, non-invasive, low-level and low-cost concept to save the error-events in a mechanical way.
  • The "logger" in the simulation is a bi-stable relay, like this one. The trivial circuits for the reporting and the resetting side are not shown in the simulation.
  • All combinations of error-states are possible, up to the scenario when A and C disconnect simultaneously and then stay disconnected. Then there would be also the (false) report of "B disconnected".

Live simulation with all three blades on Falstad (play with the switches to simulate different cases):

live simulation

Technologies: Wind Turbines, Simulation, Open Source

*Vinge Centrifugal Unit (Overspeed protection switches in the hub)

Last modified: 13.09.2019

A fully transparent, bidirectional Analog-Digital Bridge for Siemens/BONUS wind turbines

Intelligent management of the turbine hub signals.

  • stable and (in the case of our old turbines) more reliable Bluetooth connection;
  • translate all signals to digital, transmit and then recreate them on the other side;
  • watch every single signal and log all errors on a SD card;
  • even more precise than the original transmission;
  • a very extensible software, allowing to watch for much more complicated conditions;
  • enormously reducing the costs of repairing a slippery ring;
  • enormously reduction in time when searching for a problem's cause;
  • the error log can be read directly from the SD, or through an Android app.

Browse the circuit plans and the code on github:

view at github

Technologies: C, JAVA, Android, Microcontroller, Wind Turbines, Open Source

Last modified: 08.07.2018

A bluetooth interface and Android app for Siemens/BONUS wind turbines

The service technician will fall in love with it because of its effectiveness, the CEO will fall in love with it because of its cost.

  • every possible function of the original controller, but without the cable;
  • a -lot- additional features like phone call, taking and organizing pictures and notes, access to circuit diagrams, flashlight ...
  • secure two-way authentication, encrypted connection, dynamic keys;
  • macros - preprogrammed sets of repeatable actions, like starting a pump with a single click;
  • easily extensible framework, adaptable to much more wind turbines than BONUS;
  • a fraction of the cost of the original controller;
  • source code now available at GitHub!

Browse the code on github or view it in action on a 2MW AN-BONUS (Siemens) WTC2 wind turbine:

view at github

youtube video

Technologies: C, JAVA, Android, Microcontroller, Wind Turbines, Open Source

Last modified: 05.05.2019


Advanced, programmable RS485 interface

Originaly created as the hardware companion to BTDisplay, but then evolved to general purpose programmable interface.

  • fully programmable functions thanks to the integrated ATMEGA microcontroller;
  • industrial grade components with lot of redundance;
  • really small form factor;
  • general purpose LED, recharchable battery with charging circuit, magnet;
  • open-source hardware.

view at github

Technologies: Hardware, CAD, Electronics, Wind Turbines, Open Source

Last modified: 17.10.2017


Reverse-engineering the hub hydraulics of a popular Siemens/BONUS wind turbine

To help the service-technician have a better and deeper understanding on what he is working with.

  • real-time simulation with everything adjustable;
  • both electrical and mechanical componets simulated;
  • able to simulate failure-conditions.

Here goes the nice youtube video:

youtube video

The names of the components in the video are blurred on purpose.

Technologies: Hydraulics, CAD, Simulation, Wind Turbines

Last modified: 04.09.2017


Navigation app using google-maps and simple database

To quickly find the exact coordinates of a specific wind turbine.

  • search in all database fields as-you-type;
  • work with precise locations;
  • driving directions in real time with google maps;
  • updatable database.

View the source code at github or see the app in action on youtube:

view at github

youtube video

Technologies: Android, Navigation, Wind Turbines, Open Source

Last modified: 09.09.2017


A platform* to level up in over 30 different languages.

I really liked this portal*, so I joined and:

  • solved every available problem in C;
  • reviewed* as much as possible other solutions;
  • contributed to the site with implementing 15 new exercises, from the available specifications;
  • even build a python tool to automate as much as possible while creating new exercises.

* exercism.io changed the interface since.

visit the site

github repo

Technologies: C, Open Source

Last modified: 22.03.2018


A steganography tool wich features compression, encryption and (almost) non-intrusive hiding techniques.

Stide uses a new approach to steganography (hiding secrets in images) that makes detection and decryption very difficult.

  • significantly lower impact on the host image as compared to other tools;
  • randomized distribution of the embedded text;
  • the hidden message is additionally encrypted;
  • provided one uses some unique image only once, the output can be compared to a one-time-pad i.e. unbreakable;
  • Open Source;
  • linux/Windows binaries and simple gui interface included.
  • There are, however, some limitations.

view at github

youtube video

Technologies: C, Steganography, Encryption, Open Source

Last modified: 27.01.2018


The C programming language by Brian Kernighan and Dennis Ritchie | Exercises

My solutions to all exercises from the iconic book on C.

  • Single-file solutions, compile- and test-ready;
  • balanced towards simplicity, without sacrificing too much flexibility;
  • all solutions are based only on the already learned stuff in the current/previous chapters;
  • every file can compile and run with no special dependencies (except some standard library headers);
  • all compiled with: gcc -g -std=c99 -Wall -Wextra -pedantic-errors

view at github

Technologies: C, Open Source

Last modified: 01.01.2018


A funny website to create and play music

Originally created with Boomwhackers in mind, but can be used for almost any kind of music.

  • predefined melodies, which are even editable;
  • create new song from scratch;
  • download your work when ready and upload it later to use it again;
  • a fun family side-project.

view at github

visit boom-music

Technologies: HTML, CSS, JavaScript, OpenSource

Last modified: 14.09.2019


Another fun game from the childhood

A Simon game:

  • Test your memory in an ever increasing difficulty;
  • Follow the pattern created by the computer
  • You can win after repeating the last sentence of twenty steps;
  • Use strict mode for even more challenge - if you fail, the game will start over;

visit the website

Technologies: HTML, CSS, JavaScript

Last modified: 01.11.2017


The fun game from the childhood

TicTacToe game:

  • Play with a friend or against the computer;
  • The AI is a perfect player - you are welcome to try to beat it, but the best one can achieve is a draw;
  • The AI uses the minimax algorithm and chooses a random move from a set of good ones;
  • The game keeps track of all moves.

visit the website

Technologies: HTML, CSS, JavaScript

Last modified: 01.11.2017


A simple but effective management method to boost your productivity

The Pomodoro technique:

  • Decide on the task to be done.
  • Set the pomodoro timer (traditionally to 25 minutes).
  • Work on the task until the timer rings.
  • After the timer rings put a checkmark on a piece of paper.
  • If you have fewer than four checkmarks, take a short break (3–5 minutes), then go to step 2.
  • After four pomodoros, take a longer break (15–30 minutes), reset your checkmark count to zero, then go to step 1.

visit the website

Technologies: HTML, CSS, JavaScript

Last modified: 01.11.2017


Intelligent Calculator

supporting advanced synthax:

  • build as a pre-parser on top of math.js;
  • supporting parentheses, memory variable, square root, power of two, percent;
  • parse-as-you-type error checking.

visit the website

Technologies: HTML, CSS, JavaScript

Last modified: 01.11.2017


Follow your favorite streams on twitch.tv

in a quick and effective way:

  • see who is on-/offline and go to their stream on twitch.tv
  • if anyone is streaming see what they are streaming;
  • save your current list of favorites and use it again the next time;
  • search for channels/streams as-you-type.

visit the website

Technologies: HTML, CSS, JavaScript

Last modified: 16.09.2019


An interface to wikipedia.org

Quick search in wikipedia:

  • search as-you-type or see a random article;
  • the app shows the top (12) articles with short info and pics if available;
  • click on a header in the results to go to the wikipedia's article.

visit the website

Technologies: HTML, CSS, JavaScript

Last modified: 01.11.2017


Short weather info

featuring:

  • browser- or IP-based geolocation;
  • get some basic info;
  • click on the city to get to the nearest weather station.
  • switch between F° and C° by clicking on them.

visit the website

Technologies: HTML, CSS, JavaScript

Last modified: 15.09.2019


Query wikiquote.org for a random quote

features:

  • Clicking on "reload" loads new random quote and the passing image if available;
  • you can tweet the quote if you like

visit the website

Technologies: HTML, CSS, JavaScript

Last modified: 01.11.2017


A self-calculating measurements form

Solving a big real problem for a small real company.

  • massive reduction in time to process the data from the worker on-site to the customer;
  • the form calculates everything, including finding the right formula, on its own;
  • error checking;
  • on-site measurements with your smartphone only;
  • customer-ready form after a quick copy-paste in an Excel-spreadsheet

View the spreadsheets and examples on github (german description):

view at github

Technologies: Process Optimization, Forms, Open Source

Last modified: 18.10.2018


- Documents -

Wind turbines:
  • Service-Technician Wind-Turbines On-/Offshore BFW Bremerhaven. (02.2015)
German Language:
  • C1 in German from Göthe Institut Göttingen. (03.2017)
Computer science:
  • Front End Development from FreeCodeCamp. (10.2017)
  • CS50 - Introduction to Computer Science from Harvard through edX. (05.2017)
  • Machine Learning - Stanford University on Coursera. (06.2017)

- Contact -