Programming of shop window demos and conversion tools

Software: Commodore Basic, Graphic programming

Period: 1984

Development of accounting programs according to order

Software: Amiga Basic (structured), Commodore Basic, Desktop application

Hardware: Commodore Amiga, Commodore C64

Period: 1985

Customer consulting and training at a computer retailer

Client/end customer: Micro Computer Weber GmbH

Software: ARM-610 Risc-Assembler

Hardware: Acorn Archimedes Risc-Computer, Reparaturen PC-Kompatible

Period: 1987

Porting "Giana Sisters" in coproduction

Client/end customer: Escal Software GmbH

Software: Desktop application, Graphic programming, Game programming

Period: 1988

Design and programming of a travel booking portal…

Client/end customer: Travix GmbH, DER-Tours GmbH

Description: Complex determination of suitable trips and total prices from given departure and arrival data.

Software: CSS, Database modeling, Html, JavaServer Pages JSP, Perl, PHP, Web application

Hardware: IBM-PC compatible

Period: 1992

Implementation of an archiving system…

Client/end customer: Wolf & Simonis GmbH

Description: Complete development of a document archiving system, master/multi-slave architecture, scanner connection

Software: BTrieve database, Desktop application, Netware network programming, Visual Basic

Period: 1995

Development of a portable input device with radio transmission

Software: ABEL-Logikbeschreibung, H300-Assembler, PIC-1742 Assembler

Hardware: Design of ISA cards, Electronics development, Hitachi-Microcontroller, Lattice FPGA, MicroChip PIC-Microcontroller

Period: Mar. 1995

Own operating system for mobile data collection device

Software: dynamic radio network protocol, Preemptive multitaskingsystem

Hardware: Radio communication

Period: Jul. 1996

Sensor evaluation for hot runner safety system…

Client/end customer: SST GmbH, Deutsche Bahn AG

Description: Multi-threads, quasi real-time, high error redundancy, multi-master, multi-slave

Software: C++, Visual C/C++

Period: Oct. 1997 – Apr. 1998

Racing car engine control prototyping…

Client/end customer: Visteon AG, Ford Automotives AG

Description: Rush order prototype construction including coordination of project management

Hardware: Analog Technology, Design of complex control systems, Electronics development, Circuit board layout

Period: Feb. 1998 – Mar. 1998

Contract development for a biometrics manufacturer Fingerprint…

Client/end customer: Berg Data AG, Thomson CSF

Description: Hardware development PCI-card/sensor technology, real-time image driver.

Software: Ansi C, Image processing techniques, C++, Turbo Pascal

Hardware: Design von PCI-Karten, Electronics development

Period: 03.06.1998 – 25.11.1999

Own internet server on dedicated line (provider)

Software: Apache Web-Server, Remote administration, Java, JavaServer Pages JSP, Java Servlets, Linux, Security, Tomcat, Web application

Hardware: 19" Server, Industrie PCs, Raid

Period: Jan. 2000 – today

Offline data maintenance tool eTabler, Multitasking Java-Session Server

Software: Desktop application, Java, Java Servlets, Sessiontracking, Threads

Period: Jun. 2000

StadtKompass.de - Geographically oriented event portal…

Description: A nationwide calendar of events is presented at Stadtkompass.de. The aim was to get precise information with as few clicks as possible. The solution is a geographical database under which the dates can be found. In order to create a high level of satisfaction among the visitors, the geographically closest event information moves up if there are no events in the reader's catchment area. In this way, search queries without results are effectively avoided.

Software: Apache Web-Server, Geographically oriented data management, Java, Java Servlets, JDBC, Postgres, Threadpooling, Web application

Period: 11.07.2000 – 2002

Business Channel…

Client/end customer: BFL GmbH, Mphasis Europe B.V., Gruner & Jahr AG

Project: Integration of the content management system "open market" to combine 5 websites (Börse-Online, Impulse, Finanzen, Capital, Bizz) into one large web portal "Business Cannel"

Description: XML interface design and control for content delivery, data porting SQL, project documentation and partly coordination, consulting activity: technical/management

Software: Content management CMS, Documentation, Html, IPS/Openmarket, Java, JavaServer Faces JSF, JavaServer Pages JSP, Open Market Content Management, Perl, Interface specification, Web application, XML

Period: 01.10.2000 – 31.12.2000

HOTdoc - XML/DTD based offline web content management application

Software: Apache Web-Server, Content management CMS, Desktop application, Java, Java Servlets, Java Swing, JDBC, Postgres, Tomcat, XML

Period: 01.04.2001 – today

Freelancer intranet medical practice software/health card…

Client/end customer: med medicine online GmbH

Description: Debugging of the entire software and implementation of a uniform system-wide printing concept.

Software: ASP, Desktop application, Html, MS-Sql, MS-Transaction Server

Period: 01.05.2001 – 30.09.2001

Vehicle sales portal Nutzfahrzeugfinder.de…

Client/end customer: nutzfahrzeugfinder GmbH

Project: Agency portal (à la AutoScout24) for the sale of commercial vehicles of all kinds.

Description: Flexible parameterized search engine, extensive database of all commercial vehicles, login area for vehicle suppliers, administration area

Software: Apache Web-Server, Image processing techniques, Content management CMS, Database modeling, Html, J2EE, Java, JDBC, JEE, Linux, Linux Administration, PHP, Postgres, Interface specification, Security, Tomcat, Web application, Web-Templating

Period: 23.05.2001 – 15.07.2002

EMail game content management system/access rights

Client/end customer: BoST GmbH

Project: ALWS specification and implementation

Software: Content management CMS, Database modeling, Document-Processing, Documentation, Java, JDBC, Interface specification, Web application

Period: 19.09.2001 – 17.10.2001

Web based content management system…

Client/end customer: BoST GmbH, Volkswagen AG, Klett Verlag GmbH, Deutsche Verkehrswacht e.V.

Project: Realization of a web based content management system for the "learning workshop" with a flexible categorization of the articles and mapping of different categories on the page navigation.

Description: Content management system developed on behalf of a customer, which optimally supports the freely graduated navigation of the traffic education portal Lernwerkstadt. The result was a thematically indexed filing of articles. The articles are delivered by cleverly combining several topics. The content-related categorization makes it possible to change or refine the navigation without any effort. A flexible description language for the delivery of the articles enables quick adjustments to the different designs or color spaces within the presence. These design templates are also maintained within content management. Java servlets and a Sql connection to Postgres and MS-Sql servers are used. The presence implemented by the customer calls up the article view and the right teaser area. These areas are delivered completely prepared.

Software: Content management CMS, Java, JavaCC, JavaScript JS, Java Servlets, JDBC, MS-Sql, Postgres, Web application

Period: 17.08.2002 – 13.09.2002

Co-development of a CRM system for industry and wholesale…

Client/end customer: ARM GmbH

Description: Data connection and graphical user interfaces including complete networked appointment management with optically sophisticated calendar. Data export and printing of invoices through document processing via Postscript or PDF.

Software: Apache FOP, Desktop application, Document-Processing, J2EE, Java Swing, JEE, MySql, PDF, PostScript, SAP environment, XML-FO

Hardware: Scanner integration, Bar code

Period: 02.06.2003 – 11.06.2004

Implementation CMS for the internet portal "Geldidee"…

Client/end customer: Bruno Media GmbH, Gruner & Jahr AG

Description: Complete restructuring and unbundling of the internet portal. Implemetation of the Typo3 content management system. Connecting external partners sites via Typo-Script.

Software: Content management CMS, Html, JavaScript JS, PHP, Rest, Typo3, Web application

Period: 01.07.2004

mypepa - online portal for the design of photo books

Client/end customer: mypepa GbR

Software: Apache FOP, Apache Web-Server, Document-Processing, Prepress, Java, JavaScript JS, Java Servlets, JDBC, JSON, PDF, PDF-Templating, PHP, Postgres, Tomcat, Web application, XML, XML-FO

Period: 01.08.2004 – 31.07.2005

Development online photo book portal

Client/end customer: iplabs GmbH, CEWE Stiftung & Co. KGaA

Software: Java, Java Hibernate, JavaServer Pages JSP, Java Servlets, Java Spring, JBoss, PHP, Rest, Web application

Period: 01.03.2005 – 31.05.2005

PHOTUX-Client - Offline Photo Product Editor for designing photo books…

Project: Offline photo book editor including order module. Encrypted, packet-oriented data transmission, connection of payment providers, coupon / campaign system.

Description: When designing PHOTUX, the offline photo book editor, maximum flexibility was directly considered. The client software is distributed to customers free of charge and does not contain any fixed articles. The complete automatic configuration of the software takes place during the installation by the customer. During the installation or every new start process of PHOTUX, the customer is brought up to date with the latest software and offers from the photo product supplier. The photo products can be flexibly configured. In addition to meaningful descriptions in text and images, layout and production factors can also be set. Flexible prices can be set using coupon codes. For example, discounts can be granted by entering special codes or the order total can be reduced to zero by selling vouchers. Despite numerous functions and options, the Power Designer has a very clear and tidy interface. General highlights: all book pages are scrollable in one window (e.g. as with Acrobat Reader), zoom view from 20% to 800% (for a multi-column page overview up to extreme enlargement), multifunctional elements not set to image / text for Even more layout variations, all elements allow frames, background colors, transparencies and color gradients, page-by-page undo / redo function with 90 steps each, PDF export (e-mail 40DPI, screen 72DPI up to print quality 300DPI), export of all Pages of an article as images in definable sizes, transfer of an article to an Internet gallery (public or protected). The text editor: all fonts installed by the customer can be used, precise justification, text vertically above, below and in the middle, variable line / paragraph spacing, left and right paragraph inserts. The images: the image section can be conveniently selected by "scaling and moving", images are "punched out" using silhouettes, e.g. in flower or heart shape, different image sorting, e.g. According to picture name or date of recording, multi-column picture selection in selectable preview sizes, high speed even with very large pictures (we test with 90MPixel satellite photos), great detail resolution on the screen, even at 800% zoom

Software: Desktop application, Prepress, Graphic programming, Http protocols, iText, Java, Java Swing, PDF, PDF-Templating, PHP, ServerSockets, Web-Templating, XML

Period: Aug. 2005 – 30.09.2021

Production control, connection to merchandise management

Client/end customer: Vondar IO Ltd.

Software: PDF, XML

Period: Oct. 2005 – 06.06.2006

web2obj - small footprint web-server

Project: Resource-saving web server in Java, flexible URL/request mapping to Java objects, thread pooling, web socket delays (wait sockets).

Software: Http protocols, Java, Java NIO, ServerSockets, Threadpooling, Web application

Period: Feb. 2006 – today

Clexane trombose management programm

Client/end customer: Academy GmbH, Sanofi Aventis GmbH

Software: Desktop application, Real Basic (structured)

Period: 24.05.2006 – 29.11.2007

PHOTUX-Relay - Cloud-based server infrastructure for order / print data acceptance…

Project: Order data acceptance of encrypted data packets for photo book orders from several redundant servers for the purpose of load distribution / reliability.

Description: The photo book orders via the customer's PHOTUX client are sent directly to the server of the respective photo product provider. This accepts the order data and, if necessary, also handles the payment with the credit card provider. Highlights: to be used on cheap, high-availability 24/7 servers (little computing power, a lot of traffic), ordering via http port 80, which the customer normally uses with the browser, possibly processing payments or rejecting the order (e.g. for invalid credit cards) , one or more servers to accept the order data in the case of a high order volume. The order data transmitted in encrypted form in small packages is combined and is then available for transmission to PHOTUX-Prepress. The decryption of the order data takes place in-house on the PHOTUX-Prepress for the purpose of maximum security. The ability to use several servers in parallel increases accessibility and speed.

Software: Prepress, Remote administration, Http protocols, Java, Java NIO, Linux, Linux Administration, Interface specification, Security, ServerSockets, Sockets, Threadpooling, Threads, web2obj, Web application, Web service

Period: May. 2006 – 30.09.2021

data2print - System for creating and processing personalized PDF documents…

Project: XML interface for programming automatic PDF generators (mostly web to print), strict separation of PDF design from the program flow

Description: The requirement to personalize print data requires extremely flexible mechanisms to perform personalization even from irregular data sources. In contrast to the simple mail merge, which is usually only generated from similar personalized data sets, flexible data sources pose a particular challenge for personalization software. data2print reduces recurring tasks to an absolute minimum. The error-prone, tedious, constant print preparation cycle "open, edit, save" is completely eliminated: fast implementation of complex personalization requirements, composition of several data sources (XML, CSV, SQL) to different print PDFs, generation of optimized print PDFs (minimal data growth per personalized page), frequent use for regular data transmissions, generation of large quantities of individual print PDFs, periodic processing of numerous existing import files, print jobs from several paper trays with automatic post-processing (VIPP). data2print processes a configured program sequence. This control contains powerful commands for the creation and manipulation of PDF documents.

Software: Image processing techniques, Desktop application, Document-Processing, Prepress, DTP, iText, Java, Java Swing, JDBC, PDF, PDF-Templating, VIPP, web2obj, Web service, Web-Templating, XML

Hardware: Printing technology, Xerox Docucolor

Period: Jun. 2006 – today

PHOTUX-Prepress - web-based system for orders, print data generation, production control…

Project: Order data retrieval, decryption, exclusion of the photo book pages on printed sheets, print data handling, production control, campaign control, automatic payment posting via account statements.

Description: In the operation of the photo product provider, PHOTUX-Prepress runs on a powerful server. The orders are managed, processed and processed here. In order to optimally support the production processes, the system is a WEB-based solution. Different employees can control the orders from different workstations: query / retrieval of orders from PHOTUX-Relay and decryption, processing of orders via the browser within the company network, display of orders in different categories ("paid", "in production") , "Delivered" etc.), generation of invoices as PDF, booking of payments (mark as "paid"), e-mail dispatch of invoices, order confirmations, payment reminders, delivery information, perfect overview through optical symbols for the different order statuses, Conversion of the order into print-ready PDF sheets at the push of a button, journal of the status changes (time, originator) of each individual order, invoice, order and print data may be moved according to the order process, statistical evaluations. PHOTOX-Prepress can be configured extremely flexibly and adapted to different requirements. Whether a “large company” or a “small specialist”, all requests can be realized thanks to the workstation-independent control of the order processing. In the accounting department, the invoices can be easily generated in the browser and, if necessary, sent automatically by e-mail. The orders are moved to the “Open Invoices” directory (on the accounting computer) as PDF files. The invoices of the orders marked "paid" are moved to the directory "paid invoices". The printing technology clicks on all paid orders for "PDF generation". The PDFs are sent directly to the RIP via the network. The operator prints all PDFs (or hot folders). After printing is complete, all data that are “in print” are marked as “printed” and physically moved from the RIP to the “complete” directory on the archive computer. The assembled printed sheets are only produced by the photo product provider. A changeover of production or correction of the production parameters is possible at any time, even for orders that have already been ordered, paid and available for production. Extra "imposition software" is not necessary. The generated PDF print sheets are created in exactly the format to be sent to the printer on both sides with 100% scaling: Placement of the "ordered" pages on the print sheet, also in rotation, addition of various production features such as page number, barcode, registration marks, any Order of pages and arrangement in different PDFs (cover PDF, content PDF).

Software: Apache FOP, Apache Web-Server, Image processing techniques, Prepress, Http protocols, iText, Java, JDBC, JEE, Linux, Linux Administration, PDF, PDF-Templating, Postgres, Security, ServerSockets, Sockets, Web application, Web service, Web-Templating, XML, XML-FO

Period: Jun. 2006 – 30.09.2021

Realization of the internet portal Billig-Flieger-Vergleich.de…

Client/end customer: Netzpool GmbH

Project: Implementation of the server-platform of a flight-price-comparison web-page. Accessing different datasources of the airlines and travel operators, consolidating and presenting for the user.

Description: Parallel life queries of flight searches, consolidation of results (XML, CSV data), data handling and system administration. Support in the creation of the application and technical assistance in the operation of the popular portal: Cheap Flight Comparison. Here you will find a good overview of cheap flights and can compare all cheap airlines with each other.

Software: GWT, Html, JavaScript JS, JSON, Linux Administration, MySql, PHP, Web application

Period: 13.07.2006 – 12.02.2009

Website "golf comparison"

Client/end customer: Metaflake GmbH

Software: Content management CMS, PHP, Interface specification, Web application

Period: 06.09.2006 – 22.12.2006

Avalox COPD-Tool

Client/end customer: Academy GmbH

Software: Desktop application, Real Basic (structured)

Period: 27.09.2006 – 27.06.2007

CSII-Expertise

Client/end customer: Academy GmbH, Roche AG

Project: Implementing medical diagnosis software (expert-systems), that supports doctors to choose the correct medication or technical equipment (COPD, CS-II, Hypertension).

Software: Desktop application, Real Basic (structured)

Period: 26.01.2007 – 21.06.2007

Prevention Guide

Client/end customer: Academy GmbH

Software: GWT, Java, Java Servlets, Web application, Web-Objects

Period: 11.05.2007 – 10.12.2007

Hypertonie Documentation tool

Client/end customer: Academy GmbH

Software: Desktop application, Real Basic (structured)

Period: 31.05.2007 – 09.08.2007

Web based statistical system "Try And Play"

Client/end customer: Reality Bytes GmbH, Samsung Mobile AG

Software: GWT, Java, JavaServer Pages JSP, Java Servlets, JDBC, JSON, Oracle DB, Postgres, Web application, Weblogic

Period: 04.07.2007 – 07.02.2008

Coupling and single sign login of various components for the web-platform of "Young Woman’s Magazine"

Client/end customer: Reality Bytes GmbH, Burda Media Publishing KG

Software: CSS, JavaServer Pages JSP, PHP, Rest, Sessiontracking, Web application

Period: 31.07.2007 – 03.08.2007

CMS for dynamic generation of static pages

Client/end customer: Metaflake GmbH

Software: Content management CMS, Java, JavaScript JS, web2obj, Web application, Web service, Web-Templating, XML

Period: 10.01.2008

Consulting Vitaphone ISP2.0a - medication and MMI browser

Client/end customer: Star Healthcare Management GmbH, Vitaphone GmbH

Period: 14.11.2008 – 23.03.2009

Development of the "flying dinner" internet community

Client/end customer: Netzpool GmbH

Software: CSS, Html, MySql, PHP, Web application

Period: 15.11.2008 – 25.11.2008

Development "Queryserver"…

Client/end customer: Netzpool GmbH

Description: Request flight data and fares from the various flight and travel providers. Official interfaces or allowed screen scraping if no export interfaces are available. Parallel life queries of flight searches, consolidation of results (XML, CSV data), data handling and system administration.

Software: Database modeling, Remote administration, Html, Java, Java NIO, JDBC, Linux, Linux Administration, MySql, ServerSockets, sFTP, Sockets, Web application, Web service, XML

Period: 15.01.2009 – 12.02.2009

ICD/CRT Integration STAR Plus

Client/end customer: Star Healthcare Management GmbH

Period: 22.04.2009 – 22.06.2009

Print data personalization & PDF composition software…

Client/end customer: Infox GmbH

Description: Realising a print data personalization software for transforming huge incoming travel-booking-reservations in different formats into complety assembled (composing/sorting) print jobs for producing booklets. Based on my PDF-composition-library from my photobook-prepress-server.

Software: Image processing techniques, Desktop application, Document-Processing, Prepress, DTP, iText, Java, Java Swing, JDBC, PDF, PDF-Templating, VIPP, web2obj, Web service, Web-Templating, XML

Hardware: Printing technology, Xerox Docucolor, Xerox IGEN

Period: 01.06.2009 – 30.06.2017

Internet book price calculator for publisher/printing/bindery

Client/end customer: MVR GmbH

Software: CSS, Html, JavaScript JS, JSON, PHP, Web application

Period: 02.10.2009 – 29.12.2009

xwv - web/tablet based production control…

Client/end customer: profiBINDER.de

Description: Production control / control, time recording for employees and order-related production steps, generation of PDF invoices, dispatch of standard emails, e.g. with PDF attachment, feedback website for customers with display of the respective production process. The system's user interface is web-based, the times / production steps are clicked on on tablet PCs.

Software: Html, Java, JSON, web2obj, Web application, XML

Period: May. 2011 – 30.09.2021

Android App LOOKOO.de…

Project: Full-stack development of the native app and server backend. Custom geo-spatial search engine with privacy obfuscation, bespoke web services, classifieds, 400k+ events, coupons, anonymous chat, and persistent waiting sockets replacing HTTP polling.

Description: Full-stack architecture, end-to-end development, and five-year lifecycle maintenance of the native Android application "LOOKOO.de" alongside its comprehensive custom server backend as a high-traffic regional discovery and social platform. Designing and engineering a high-performance geo-spatial search engine for location-based networking, events, and coupon aggregation, incorporating privacy-preserving obfuscation algorithms for search results within a 2 km radius. Developing custom web services and backend APIs from scratch for seamless data orchestration and client communication. Building a scalable communication framework supporting anonymous chat IDs, global user discovery, and robust anti-spam protection against mass messaging. Core engineering focus centering on designing a low-latency, quasi-real-time messaging engine using persistent waiting sockets instead of traditional HTTP polling to guarantee minimal response times. Integrating self-developed server infrastructure for synchronizing over 400,000 regional events, classifieds, and location-based discount models, ensuring encrypted data transmission (SSL/TLS) to European server deployments.

Software: Android, Java, Kotlin, Interface specification, Sockets, Web-Objects, Web service, XML

Period: Jun. 2013 – 01.06.2018

Facebook data interface for events…

Project: Data interface for events and automatic online marketing on Facebook.

Description: Automated query of all event information from Facebook. Access is via the open, official Facebook interface "Open Graph" in XML format. Since not all data can be queried via this interface (in particular, the image references there point to reduced versions), the high-resolution images and other information must be captured by screen scraping.

Software: Database modeling, Facebook Open-Graph, Geographically oriented data management, Java, Postgres, RestFB, Web application, XML

Period: Oct. 2013 – 16.04.2018

PHOTUX-Track - Android shipping control…

Project: Development of a client-server app for print fulfillment workflows. Streamlined operations via barcode scanning, image processing, bundle grouping validation, automated shipping cost calculation, and dynamic PDF templating for labels and manifests.

Description: Architecture and end-to-end development of a native Android client-server application designed for automated control and quality assurance in fulfillment workflows for personalized print products (photo books, calendars). Engineered robust barcode-scanning pipelines featuring asynchronous image processing and instant cover-photo rendering for immediate visual verification post-scan. Implemented complex business logic for grouping and bundle validation (Zupackartikel): the system verified order completeness, automatically blocking label generation and triggering alerts if companion items were missing. For complete lots, integrated dynamic algorithms to calculate accurate shipping costs and optimal packaging sizes. Developed a high-performance PDF-templating engine to automate the generation of shipping labels, packing lists, and dispatch manifests containing cover thumbnails and postal routing codes for postal drop-off. Implemented an integrated image-capture pipeline to securely document packaged items prior to final dispatch. Connected to backend systems via HTTP protocols, XML interfaces, and web services for real-time order status tracking ("delivered") and dispatch notifications.

Software: Android, Http protocols, Java, PDF-Templating, Interface specification, bar code, Web service, XML

Period: 14.04.2015 – 26.05.2015

Android VoIP softphone app…

Client/end customer: technidoo UG, Swyx Solutions AG

Project: Development of a native VoIP softphone for SwyxWare. Custom SIP stack modifications, iOS-parity history management, server synchronization for contacts/favorites, and seamless integration of Android Bluetooth and car audio stacks for headsets.

Description: Architecture and end-to-end development of a native Android VoIP softphone client tailored for enterprise integration within the SwyxWare PBX environment. Designed and executed deep modifications to the SIP communication stack to accommodate proprietary Swyx protocol deviations, ensuring rock-solid registration, signaling, and call handling. Developed a sophisticated UI layer and engineered a complete overhaul of the history management subsystem to achieve strict iOS cross-platform parity. Implemented a robust audio routing architecture featuring tight integration with the Android Bluetooth stack (managing HFP/A2DP profiles for wireless headsets) and car audio systems, including proper audio focus handling and hardware button routing. Implemented high-performance local database modeling and server synchronization pipelines utilizing Retrofit, Jackson2, and RxJava for enterprise contacts, recent call logs, and favorites. Ensured mission-critical application stability and maintainability through advanced dependency injection (Dagger) and comprehensive automated test suites using JUnit, Mockito, and Espresso.

Software: Android, Ansi C, Butterknife, Dagger, Database modeling, Espresso, Glide, Http protocols, Jackson2, Java, Junit Tests, Mockito, ReactiveX/RxJava, Retrofit, SIP Protocol, XML

Project management: GIT, Gradle, Jenkins, Maven, Scrum

Period: 03.09.2015 – 02.12.2016

IoT radio module ("Dashbutton") with battery charging via USB…

Description: Network: Connection via WLAN - WIFI 2.4G ~ 2.5G (2400M ~ 2483.5M) 802.11 b / g / n / e / i. Connections: Connection for 4 buttons with protective circuit (IEC 61000-4-2 ESD Protection (Level 4), ± 8-kV Contact Discharge, ± 15-kV Air-Gap Discharge) - with wake-up function from sleep mode; Connection for 4 digital sources - with wake-up function from sleep mode Connection for 2 analogue sources. Signal generator: Multi-colored LED for visual status messages: blue "in progress", green "ok", red "error" (can be switched off), beeper for acoustic notification of status or error messages (can be switched off). Power supply: Power supply via USB and / or battery (Li-Ion) with automatic switchover and battery trickle charging, intelligent charging circuit with various protective circuits (500mA USB input current limit, inrush current limiter, precharge and fast-charge safety timers, termination current, reverse current , Short-Circuit, Thermal Protection), Two Li-ION battery options: 18650 (∅18mm, length 650mm) or the smaller variant 18350 (∅18mm, length 350mm); 3.3V voltage regulator: up to 96% efficiency, buck-boost (use of full battery capacity), shutdown at 3.15V (to protect the battery), overtemperature protection; Reliable, stable and vibration-proof battery holder thanks to spring clips. Energy management: Long runtime thanks to extremely energy-saving (0.02mA / 20µA) operation with the 3.3V voltage regulator switched off in sleep mode (waiting for the next action or safety timer); Safety - Safety features: Configurable control interval (safety timer) for self-diagnosis: battery level, WLAN connectivity, etc.

Software: Ansi C, FreeRTOS, PIC-16 Assembler, Interface specification, Threads, XC8

Hardware: Analog Technology, Design of complex control systems, Electronics development, ESP-Microcontroller, Radio communication, Gatter, Li-Ion charging technology, MicroChip PIC-Microcontroller, Microprozessoren, Circuit board layout, Circuit design, Circuit design

Period: 01.01.2017 – 31.07.2017

IoT configuration web interface

Software: Ansi C, CSS, Html, Http protocols, JavaScript JS, Interface specification, Typescript, Web application, XML

Period: Mar. 2017 – today

IoT sensor module (temperature / humidity)

Project: Sensor platform for sensors for connection to the IoT radio module via a MultiMaster RS485 bus.

Software: Ansi C, PIC-16 Assembler, Interface specification, Threads, XC8

Hardware: Analog Technology, Design of complex control systems, Electronics development, MicroChip PIC-Microcontroller, Microprozessoren, Circuit board layout, Circuit design, Circuit design

Period: 01.08.2017 – 10.01.2018

Certificate management

Client/end customer: Bank-Verlag GmbH

Software: Java, JavaScript JS, JavaServer Pages JSP, Java Servlets, JSON, PHP, Rest, Interface specification, sFTP, Typescript, Web application

Project management: GIT

Period: 09.10.2017 – 03.11.2017

Facebook Screen-Scraper…

Project: Screen-scraping interface for automatic online marketing on Facebook.

Description: Completely newly developed Facebook interface through screen scraping. The open, official Facebook interface "Open Graph" was blocked almost 100% (data scandal due to "Cambridge Analytica").

Software: Database modeling, Geographically oriented data management, Java, Postgres, Typescript, Web application, XML

Period: 16.04.2018 – today

Implementation of an UpdateManagement configuration system …

Client/end customer: CompuGroup Medical AG

Project: Design and implementation of an update management system. Consolidated SAP customer data with IT infrastructures, license mapping, role and group management for sub-companies, audit trail, 4-eye approval, and statistics using Java, JBoss, Angular 6, and MySQL.

Description: Consolidation of customer data from SAP with information about the customer's IT infrastructure from an update package management system. Linking the update packages with the appropriate software suites licensed by the customer. Assignment of updates to the computer systems of the desired customers (groups). Comprehensive group and rights management, access filters at the various sub-companies of CompuGroup AG, detailed audit trail, 4-Eye confirmation and statistical evaluation of the installation status of the various software packages.

Software: Angular 6, CSS, Java, JavaScript JS, Java Servlets, JBoss, Jetty, MySql, ReactiveX/RxJava, SAP environment, Interface specification, SCSS, Typescript, Web application, Web service, Web-Templating

Project management: Confluence, GIT, Jira, Maven

Period: 18.06.2018 – 28.09.2018

Further development of a house control app…

Client/end customer: Gira Giersiepen GmbH & Co. KG

Project: Enterprise evolution and legacy migration (GCM to FCM) of a KNX smart home app for heterogeneous hardware. Delivered WebRTC video streaming for IP intercoms, IoT sensor integration, server-driven UI, and a resilient offline-first architecture.

Description: Comprehensive enterprise-grade evolution, legacy migration, and architectural modularization of a mission-critical Java application designed for holistic KNX building automation and interfacing with the Gira HomeServer. Engineered and maintained a robust multi-flavour architecture enabling a unified codebase to power highly heterogeneous hardware targets—ranging from fixed in-wall wall tablets and the dedicated KNX room control device Gira G1 to mobile Android smartphones. Spearheaded the design and implementation of low-latency real-time media streaming modules for IP door intercom systems utilizing WebRTC, securely integrated across network segmentations and specialized firewall architectures (Gira F1 Bridge). Implemented low-level, hardware-adjacent IoT sensor logic for device-context awareness, including proximity detection for automated display wakeup/dimming and the end-to-end architecture of an automated, adaptive day/night mode driven by ambient light sensors. Designed a server-driven UI configuration engine where layout definitions, control states, heating/blinds telemetry, and statistics were dynamically parsed, bound, and rendered from the Gira HomeServer backend. Engineered a resilient offline-first architecture to guarantee uninterrupted operation during network outages, featuring local state persistence, background reconciliation queues, and automated UI re-configuration upon server reconnection. Executed a critical legacy migration of the push notification infrastructure from Google Cloud Messaging (GCM) to Firebase Cloud Messaging (FCM), alongside deep structural modularization to eliminate tight coupling, resolve concurrency bottlenecks, and streamline complex inter-process and inter-module communication.

Software: Android, Java, Kotlin, Rest, Web service

Project management: CI/CD, Confluence, GIT, Gradle, Jenkins, Jira, Scrum, SVN

Period: 01.10.2018 – 31.08.2020

Online Course Editor…

Project: Online editor for designing online courses for integration into learning platforms.

Description: The layout and the learning content are entered in an online editor. Audio/video sequences can be placed and supplemented with dynamic text. A course consists of different chapters and timelines. These timelines allow the specification of time intervals or video/audio positions in/at which the different learning contents are presented. Jumps within the courses are done by deep links and bookmarks. The review of the learned subjects is done through questions/answers. These answers redirect to repetitions or to more intensive descriptions.

Software: Apache Web-Server, CSS, Html, Java, JavaScript JS, Linux, Linux Administration, Typescript, web2obj, Web application, XML

Period: 15.09.2020 – today

Identification and evaluation of trading strategies for the stock market…

Client/end customer: Crystalline Analytics Ltd.

Project: Development of a desktop application for evaluating and backtesting stock market trading strategies. Implemented deep learning components and a high-performance Java Swing custom graph painter for detailed result visualization using XML data.

Description: Architecture and standalone development of a high-performance desktop application dedicated to the systematic discovery, backtesting, and evaluation of stock market trading strategies. Integrated deep learning models for predictive pattern recognition. Designed and engineered a custom, responsive user interface using Java Swing, featuring a dedicated, highly optimized graph painter component for smooth real-time graphical visualization of multi-variable financial charts, performance metrics, and simulation results. Managed data exchange, state persistence, and configuration structures via XML data models.

Software: Deeplearning, Desktop application, Java, Java Swing, XML

Period: 15.12.2020 – 31.12.2022

High-Secure smart building update management…

Client/end customer: Breuer Nachrichtentechnik GmbH

Project: Development of a high-security software update management system for military infrastructure and bunkers using a zero-trust architecture. Engineered multi-level, encrypted software updates by authorized technicians via USB tokens and sFTP.

Description: Architecture and backend development of an ultra-secure software update management system tailored for military installations and underground bunker infrastructure under strict government security clearance protocols (SÜ2). Designed and enforced a strict zero-trust operational model to mitigate physical and cyber-attack surfaces. Implemented a multi-tier authorization and verification pipeline allowing software updates to be executed solely by vetted technicians using cryptographic security keys stored on physical USB hardware tokens. Developed core server-side logic (JavaServer Pages, Java Servlets) and secure sFTP data transfer and validation routines in hardened Linux environments.

Software: JavaServer Pages JSP, Java Servlets, Linux, sFTP

Project management: GIT

Period: 15.07.2021 – 30.09.2021

Development of entry and processing of "hardship case" for authorities…

Client/end customer: Proximity GmbH

Project: Development of a digital application and case management platform for public authorities (hardship commission for foreign nationals) using the Lucom platform. Implemented complex multi-step workflows with loop logic for staff and external board access.

Description: Architecture and backend implementation of a highly complex e-government web application designed for digital case processing and application management within official hardship procedures for foreign nationals, utilizing the Lucom Interaction Platform. Engineered sophisticated multi-step workflow logic featuring iterative review loops, return paths, and status transitions for internal case workers. Integrated secure external access channels for members of the hardship commission to enable decentralized evaluation, commenting, and decision-making. Managed server-side document processing, web templating, and interface design (HTML/CSS/SCSS, JavaScript) across Linux and Tomcat server environments.

Software: CSS, Document-Processing, Html, Java, JavaScript JS, Linux, Linux Administration, Lucom, SCSS, Tomcat, Web application, Web-Templating

Project management: Confluence, GIT, Jira, Maven

Period: 06.09.2021 – 30.11.2021

System Architecture Datawarehousing…

Client/end customer: targit GmbH

Project: Redesign of the data warehousing system architecture focusing on extreme performance optimization. Comprehensive analysis of legacy workflows, achieving a 300+ fold acceleration in data processing (reducing runtime from 22:40 min to 4 sec) using Java, Spring, and advanced SQL for massive infrastructure savings.

Description: End-to-end analysis, reengineering, and redesign of the enterprise system architecture for data warehousing, focusing on drastic performance scaling and infrastructure cost reduction. Conducted deep-dive audits of existing system bottlenecks, data processing pipelines, and query inefficiencies. Architected and implemented a high-performance processing engine utilizing Java, Spring, and advanced SQL optimization techniques. Achieved a breakthrough performance acceleration of over 300x, successfully reducing critical data batch processing times from 22 minutes and 40 seconds down to just 4 seconds. This architectural transformation delivered immediate, significant reductions in server infrastructure overhead and operational resource consumption.

Software: Java, Java Spring, SQL

Project management: CI/CD, GIT, Jira, Maven

Period: 01.02.2022 – 30.06.2022

Frontend for document aggregation…

Client/end customer: EQS GmbH

Project: CMS editor for updating a jusritic expert system from new given documents (PDF)

Description: Update of a jusritic expert system from new given documents (PDF). Detection and merging of all changes (incl. new chapters and shifts). Clear display of conflicts and marking of all detected changes.

Software: Content management CMS, Desktop application, Document-Processing, Java, Java Swing, PDF, Interface specification, Threads

Project management: GIT, Jira, Maven

Period: 15.11.2022 – 28.02.2023

Sailschool-/Charter-/Landtours-Cyprus.com…

Project: Implementation of 3 travel portals for the Cyprus turism industry

Description: The comprehensive directory for all tourism activities. Attractive overview of the offers in short and long form, text extraction from the product description, preparation of the photos. Comprehensive backend for providers to enter offers, keywords, item details.

Software: CSS, Html, Java, JavaScript JS, Linux, Linux Administration, Tomcat, Web application, Web-Templating

Period: 01.03.2023 – 20.07.2023

Development of a form system for governments…

Client/end customer: InterOne GmbH

Project: Development of complex public authority form workflows using the Lucom platform (incl. "Mein Unternehmenskonto", IfSG, foundation forms). Implementation of SAML/oAuth, Apache FOP PDF generation, Java web apps, Tomcat, and Docker on AWS.

Description: Architecture, development, and scalable backend implementation of complex public sector online form workflows and digital application portals (e.g., for IT.NRW) using the Lucom Interaction Platform. Realized mission-critical e-government applications including the integration of "Mein Unternehmenskonto" (BundID/ELSTER identity structures), the IfSG (Protection against Infection Act) form, and specialized foundation application forms. Implemented secure authentication and authorization workflows utilizing the SAML protocol and oAuth. Engineered server-side document processing pipelines for the automated generation of official PDF notices and application documents via Apache FOP and web templating (HTML/CSS/SCSS, JavaScript). Managed containerization, Linux administration, and deployment of enterprise Java web applications across scalable Apache Tomcat and Amazon Web Services (AWS) environments, integrated with continuous delivery pipelines via Docker and Maven.

Software: Amazon Cloud AWS, Apache FOP, CSS, Docker, Document-Processing, Html, Java, JavaScript JS, Linux, Linux Administration, Lucom, oAuth, SAML Protocol, SCSS, Tomcat, Web application, Web-Templating

Project management: CI/CD, Confluence, GIT, Jira, Maven

Period: 01.06.2023 – 30.06.2024

Museum application for interactive visitor communication…

Client/end customer: Museumsverein Morsbroich e.V.

Project: Design of an interactive visitor communication app on industrial PCs. Implemented a system lockdown for 24/7 operation, a local editorial backend with auth and bad-keyword filters, real-time input sanitization, and automated dynamic beamer projection.

Description: Architecture and comprehensive development of an interactive visitor communication and moderation platform running on secured industrial touch PCs and kiosk hardware. Engineered a robust, custom Android system lockdown to guarantee secure 24/7 public exhibition operation. Designed a hidden, local editorial backend featuring two-tier authentication (Admin/Editor roles), a configurable bad-keyword filter, and dynamic styling options. Implemented advanced, real-time input sanitization directly within the edit fields (blocking emojis, repetitive special characters like *, and excessive whitespace while preserving manual line breaks and text length limits) alongside multi-language support (including Arabic layout handling via Google Keyboard). Developed an automated dynamic scaling and projection algorithm that outputted approved visitor comments via beamers as visual text blocks, inversely scaling font sizes relative to text length for optimal legibility. ​Software: Android, JetPack, JetPack Compose, Kiosk Lockdown, Kotlin, Multi-threading, XML, Custom Input Filtering, Dynamic UI Scaling

Software: Android, JetPack, JetPack Compose, Kiosk system, Kotlin, Threads, XML

Period: 07.05.2025 – 14.08.2025

DHL Android App…

Client/end customer: DHL Paket GmbH

Project: Enhancement of the enterprise delivery driver app on Zebra handhelds with a primary focus on tracking down and fixing rare, critical bugs. Handling offline-online state synchronization, route management, locker workflows, and Bluetooth label printing via ZPL/CPCL.

Description: Further development, stabilization, and architecture optimization of the mission-critical DHL delivery driver application running on Zebra handheld devices. Focused on mastering complex, real-time data flows within a sophisticated multi-threading environment. Responsibilities included robust handling of live barcode scans, seamless offline-online state synchronization, dynamic route management, and logistics workflows for servicing and filling DHL service point lockers. Additionally, implemented a stable print history and reprint mechanism communicating directly via Bluetooth with mobile label printers utilizing text-based ZPL/CPCL print commands.

Software: Android, Android Koin, JetPack, JetPack Compose, JSON, Junit Tests, Kotlin, Interface specification, Threads

Hardware: Bar code

Project management: Confluence, GIT, Gradle, Jira

Period: 01.02.2026 – 15.06.2026

High-Performance Linux Security Camera Daemon & Real-Time Motion Analytics…

Project: Multi-channel security camera pipeline engineered in C. Features resource-efficient in-memory ring-buffers, signal isolation, and hot-restart recovery for maximum uptime.

Description: Engineered a multi-process C daemon supervising real-time camera streams via custom Linux workers managed by an interactive parent supervisor loop with signal isolation and hot-restart recovery. Designed an in-memory rolling ring-buffer cache mapping pre-alarm histories, utilizing localized luminance analysis grids and dynamic downscaling to optimize motion thresholds. Eliminated critical memory leaks and deadlocks, dropping the production RAM footprint to a flat, stable <15MB per channel.

Software: Ansi C, Bash, Gnu C/C++, Http protocols, Linux, Preemptive multitaskingsystem, System programming, Threads

Hardware: Industrie PCs

Period: 15.06.2026 – 01.09.2026