JR-Projects – Apps & 3D Printing that truly advance your ideas
At JR-Projects, I combine technical expertise with genuine passion for digital products and 3D printing. I support you from the initial idea to the finished product.
Native & Cross-Platform Apps
I develop native apps for Android and iOS as well as cross-platform solutions with Kotlin Multiplatform (KMP). This way you reach both platforms with a shared codebase – without compromising on performance or user experience.
For backend and data management, I rely on Firebase: databases (Firestore), authentication, Cloud Functions and analytics – scalable building blocks for production-ready apps.
- Native Android & iOS development
- Kotlin Multiplatform for shared business logic
- Firebase backend (Firestore, Auth, Functions)
- From idea to App Store / Play Store release
Consulting & Concept
Together we analyze your requirements and develop a viable concept for your app.
Design & Prototyping
From wireframe to clickable prototype – see early how your app will look and function.
Development
Native iOS/Android or cross-platform with KMP – implemented with modern technologies.
Backend & Cloud
Firebase databases, auth and cloud functions – scalable and low maintenance.
From idea to functional part
My 3D printing journey began in 2012 during my electrical engineering studies with a self-built 3D printer. Since then, I have consistently expanded my equipment and know-how. Today I operate a small 3D printer farm with modern devices, including multi-color prints via color change.
I turn your idea into a tangible result – as a one-off, prototype, or small series. The focus is not just on "looks good" but on function, fit, and everyday usability.
- CAD design & construction according to your requirements
- Printability check (tolerances, wall thicknesses, stability)
- Materials & processes suited to your application
- One-offs, prototypes & small series
CAD Design
I design your part from sketch, photo or description – iteratively refined until it fits.
Print Optimization
Printability check: tolerances, wall thicknesses, orientation and stability.
Material Selection
PLA, PETG, ASA, TPU and more – depending on load, temperature and application.
Manufacturing
One-offs to small series – with consistent quality and short delivery times.
In the Etsy Shop
Customizable Keychains
Multi-color, individually designed
View on Etsy →
Cup & Bottle Holder
Custom fit for Fiat Ducato
View on Etsy →
PC Fan Mount
DIY for Dometic refrigerator
View on Etsy →Reviews from the Etsy Shop
"The service is absolutely outstanding! Professional! Production and shipping super fast! Beautiful quality! I'm thrilled with the result and will definitely order again!"
"Jan is super helpful and answered my questions in detail. The product arrived beautifully packaged and there were small gifts included. Thank you so much!"
"So great, I've been looking for this for 2 years without having to replace my roof window!"
"Thank you for the competent advice. You can feel that at JR Projects the customer comes first. My questions were taken seriously and answered patiently."
"As described, it fits exactly! I wouldn't want to be without it in my camper anymore."
"Great product and top quality. Ideal gadget for carnival season – never again the question: Which beer was mine?"
The DIY Wordclock
Ready for a maker project? With the NiftyChronoMaster kit, you build a high-quality wordclock that displays time in words – supported by an 11x10 RGB LED matrix, clean CAD design, and well-thought-out firmware.
- 11x10 RGB LED matrix for flowing word display
- Available as Mini or Battery variant
- High-quality CAD parts and thoughtful design
One contact, two worlds
You typically need either an app/software solution or help with CAD & 3D printing – and in many cases these are completely different projects. That's why I offer both areas clearly separated, so you get exactly what you actually need.
And if combining both makes sense for your case (e.g. prototype + app, IoT, accessories with a digital companion), you benefit from someone who keeps the hardware/software interfaces in mind. This keeps your project consistent – without coordination overhead.