Project — Lockcard · 2019–2024
Co-founded with Jonas Weber straight out of high school. Bootstrapped to €2.8M annual revenue and €1M profit — own production in Ulm, 13 people, 150,000+ customers. Sold in November 2024.
01 — Revenue
No investors, no loans — every euro was reinvested. From one 3D printer in a student dorm to 1,000 m² of factory and office space:
02 — Die Höhle der Löwen
Photo: RTL / Bernd-Michael Maurer
With Ralf Dümmel, DS Gruppe
We pitched on Germany's Die Höhle der Löwen (VOX) in 2022. The first application, a year earlier, had been rejected.
→All five investors made an offer.
→We closed with Ralf Dümmel and Carsten Maschmeyer — structured as a cooperation through their distribution and production network, with no equity given up.
→The deal ran under NDA for the year between recording and broadcast.
03 — Production
In-house production was the speed advantage: a design change that takes weeks through a contract manufacturer took hours on our own machines. The only step outsourced was anodizing.
Four locations in five years: a 10 m² student dorm, my parents' basement, a 250 m² workshop, then 1,000 m² in Ulm — capacity for 150 products a day, with a shipping station that packed 130 packages an hour.
Iterations were part of the product culture — the office had a display cabinet with every prototype generation, from the first FDM prints to the final SLS parts.
04 — Sales
Screen recording of the shop, January 2025:
05 — The product system
Two cover plates and an ultrasonic-welded elastic band — patented — hold interchangeable modules: cards, keys, coins, SD cards, trackers. Modules came out of community requests and went through dozens of prototypes each.
Product renderings — wallet system
Beyond the wallet
06 — Chaospendel
Wall object, CNC-milled from 6 mm aluminum, on two-row ball bearings. The rear arm pivots near its center, the front arm at a third of its length — the free ends act as counterweights and keep the motion slow. Sold in limited runs — resold later for up to €600. The simulation uses the measured geometry — drag it.
Drag the pendulum
07 — Exit
Jonas and I sold 100% to a successor who had been a partner of the company.
Before the handover I documented every critical process in an internal video wiki; the team stayed on. The patents on the band weld and the packaging are my inventions from this time. Afterwards: a year of travel, then Shenzhen.
