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Projects
Fifteen pieces of work from three directions: software meant to run in retail and everyday life, apps for Android and devices I have built. Each entry shows how far along it is.
Products & software
Applications that take over a specific workflow. Some are publicly available, others are built for one particular business.
Kontor
Retail management system for a bricks-and-mortar sports shop: products, customers, receipts, till with TSE connection, ski rental, workshop, stocktaking and annual archive in one application. Replaces a system that grew over more than twenty years, whose workflows the shop still needs.
- Aktenlage Windows program that scans paper, reads the content and files it by itself. Runs without a cloud and without an account. One-off purchase, 50 pages free to try. Live
- Artikel-Anleger Turns incoming goods into finished Shopware products: duplicate check, categorisation, researched texts, approval by a human. In development
- Muskelkater Sport Custom Shopware 6 theme for a sports shop in Cologne, including a rental calculator and the migration of products from the old system. Live
- BeepHunt Finds a beeping device in the home: recognises the sound, tracks it and says warmer or colder while walking around. Submitted to Google Play
- Merger Number puzzle for Android, fully playable in the browser: blocks are shot into the field from below, equal numbers merge. Free, no ads, offline. Play Store listing in progress
- Squishly Endless jumping game for Android, in the Play Store since August 2026. Every graphic is drawn in code, no image files. Live
- Household budget Household budget, property calculator and repayment plan in the browser. The entries never leave the device. Live
- Fabrikon Idle tycoon for Android with 24 factories and fully calculated production chains. Closed test
- Tendly Habit tracker for Android, in the Play Store since August 2026. Every habit is a plant; the garden grows along with it. Live
Nothing in this group matches the selected status at the moment.
Hardware & experiments
Devices that have been built, and physics to try out. The control logic of each also runs here in the browser, so it can be tried without the device.
ArmControl
Four-axis robot arm on stepper motors, with its own firmware and its own control software featuring inverse kinematics and 3D simulation. In the browser demo, the kinematics use the same calculation as on the device.
- Cocktail machine ESP32 with firmware in Rust. The device serves its own user interface, without a server; no app is needed. Demo
- Aperol machine Arduino Nano, three pumps via MOSFETs, five strength levels and a calibration that stays in the EEPROM. Demo
- Busfahren The pub game as a handheld: Arduino, 16×2 LCD, a potentiometer and a push button. Demo
- Engineering playground Crank drive, gears, damped oscillation, vortex street and Fourier series to turn yourself. Demo
Nothing in this group matches the selected status at the moment.
Adaptations and enquiries
Kontor and the Artikel-Anleger were created for one particular business but can be transferred to similar workflows. Enquiries about the applications, about adaptations or about evaluating your own measurement data go through the contact form.