JR-ProjectsApp developmentand 3D printing
Ideas, built layer by layer.
I am Jan. I build apps for iPhone and Android and design parts you cannot buy off the shelf. I developed the wordclock in the photo myself: housing from my 3D printer, firmware written by me.
Years of software development
Started at university, since then in my own and client projects: Android, iOS and today mostly Kotlin Multiplatform with Firebase.
My first 3D printer
Designed and built myself during my electrical engineering studies. Several self-built printers ran side by side for years. Today I print on modern machines.
Quantity depends on size
A full plate of small parts prints in a few hours. One part the size of the print bed takes about a day per printer.
Until I reply
Usually faster. The first conversation is free, even if you only have a rough idea.
Your app for iPhone and Android, from one codebase
I write your app once in Kotlin and ship it to both platforms. So you do not pay for two separate apps. Where needed, for example for the camera or maps, I use the native iOS and Android interfaces.
Clickable prototype
We clarify who uses the app and what it must do on day one. Then you get a prototype to click through.
Test builds on your phone
You install work-in-progress versions on your own device and give feedback early.
Login, data, push
Firebase for database, login, push notifications and files. A browser admin panel if you need one.
Release and updates
I submit the app to Apple and Google and keep it up to date with new system versions.
One group.
One chat.
Everything in it.
Packing list, shared expenses and meeting points live right inside the group chat, for trips, stag and hen parties, camping and festivals. I built the concept, design, app and backend myself.
Chat
One chat per event with photos, voice messages, polls and push notifications. Direct messages too.
Packing list
Create it together and tick items off in real time. Who brings the tent, who brings the adapter?
Shopping New
A shopping list sorted by your route through the store. Snap the receipt and items and prices go straight into the shared expenses.
Expenses
Split by attendance, exact amounts or percentages. The app suggests the fewest settle-up payments.
Map Meeting points new
Your crew live as avatars, custom meeting points, an alert when you get close. Location is shared only with the group and stops after three days.
Events & search New
Plans for the trip, a calendar across all groups and search across lists, tasks and expenses.
What it looks like in the app
- Everything at a glanceThe next event with a countdown and what happened in your groups.
- Packing listWho brings the grill and who has already packed it.
- Shopping listTick off what is in the cart. Everyone sees it instantly.
- Scan receiptsTake a photo and items and prices land in the expense.
- Split costsWho paid and who owes whom how much. No spreadsheet.
- Search everythingOne field for groups, lists, tasks and expenses.
Spare parts, mounts and prototypes from the 3D printer
Send me a photo of the broken part, a sketch or your STL file. I take measurements, design the part in CAD and print it in the material that suits the job. From a single spare part to a small series.
- 2012
During my electrical engineering studies I build my first 3D printer. I design the mechanics, electronics and settings entirely myself.
- The years after
Several self-built printers run side by side for years. That is how you get to know every material and every print failure.
- Today
Modern printers with automatic colour and material changes. That means multicolour parts in a single print.
Parts I have designed and printed
What buyers say in my Etsy shop
Reviews are quoted in their original German.
„So toll, ich habe 2 Jahre lang danach gesucht, ohne mein Dachfenster austauschen zu müssen!"
„Jan ist super hilfsbereit und hat meine Fragen ausführlich beantwortet. Das Produkt kam schön verpackt bei mir an."
„Super Artikel und top verarbeitet. Nie wieder die Frage: Welches Bier war jetzt meins?"
NiftyChrono: the wordclock you build yourself
Instead of digits, words light up. Behind the front sit 110 individually addressable RGB LEDs. The kit comes as a Mini with power supply or with a battery. Use the slider to try out time and colour. The photo shows the German front.
Hi, I am Jan
I learned programming, CAD and 3D printing during my electrical engineering studies. That is also where I built my first 3D printer from scratch. I kept going in my spare time, and that became JR-Projects: apps, spare parts and custom builds for people looking for something you cannot buy.
In my main job I lead projects at a large engineering company. You benefit from that here too: clear agreements, a written quote and realistic deadlines.
You have one contact person, from the first call to delivery. My workshop is in Regensburg, Germany, and I ship parts worldwide.
- Studies
- Electrical engineering
- Main job
- Project manager in engineering
- Software
- 10+ years, today mostly Kotlin Multiplatform
- 3D printing
- since 2012, starting with my own printer
- Workshop
- Regensburg, Germany
- Shipping
- worldwide
Good to know
Do you only work with clients in Regensburg?
No. Calls happen by phone or video, in English or German, and I ship parts worldwide.
How quickly will I get a reply?
Usually within 24 hours. The first conversation is free and without obligation, even if you only have a rough idea.
Do you also do projects that combine an app and hardware?
Yes. For devices with app control or prototypes with electronics I know both sides. My wordclock is one of those projects: housing from my 3D printer, firmware written by me.
Tell me about your project
A few sentences are enough. I usually reply within 24 hours, and the first conversation is free.
- You write to meFor parts, ideally with photos and dimensions. For apps, a short description of the idea.
- We have a quick callBy phone or video, in English or German. We clarify what you need and by when.
- You get a quoteIn writing, as a fixed price or based on effort. Take your time to decide.