♻️ Mülltrennung App

Scan any product barcode to instantly find out which bin it belongs in — built for expats and residents in Germany.

Germany has one of the most complex waste sorting systems in the world: up to 6 different bins, rules that vary by city, and labels that assume you already know the system. This app removes the guesswork.

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Features

• Barcode scanner — point at any product and get an instant bin recommendation
• City-aware rules — rules differ between Berlin, Hamburg, Munich, Frankfurt, and Cologne
• English-first — designed for expats and newcomers; toggle to German at any time
• Bin guide — plain-English reference explaining every bin type in Germany
• Scan history — last 50 scans saved locally on device
• Product images — pulled from Open Food Facts when available
• Offline-capable — city rules bundled with app, no internet needed for lookups
• Tip system — contextual tips per item (e.g. "rinse the can", "flatten the box")

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Supported Cities

City	Bundesland
Berlin	Berlin
Hamburg	Hamburg
Munich	Bavaria
Frankfurt	Hesse
Cologne	NRW

More cities coming soon. Rules are version-controlled JSON files — contributions welcome.

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Tech Stack

Layer	Technology	Why
Framework	React Native (Expo)	Single codebase for iOS/Android
Language	TypeScript (strict)	Type safety across rules/UI
State	Zustand	Lightweight global state
Product data	Open Food Facts API	3M+ item open database
i18n	Custom hook	English + German, no deps
Navigation	React Navigation	Standard mobile tabs
Rules	Typed JSON + TS service	Offline, version-controlled

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Getting Started

Prerequisites

• Node.js 18+
• Expo CLI: npm install -g @expo/cli
• Expo Go app: iOS / Android

Installation

git clone https://github.com/danielamissah/mulltrennung-app.git
cd mulltrennung-app
npm install
npx expo start

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Project Structure

src/

• components/
  • BinCard.tsx — Coloured result card with tip
  • CityPicker.tsx — Horizontal city selector chips
  • LanguageToggle.tsx — EN/DE toggle pill
• data/rules/
  • berlin.json — Berlin-specific bin rules
  • hamburg.json — Hamburg-specific bin rules
  • munich.json — Munich-specific bin rules
  • frankfurt.json — Frankfurt-specific bin rules
  • cologne.json — Cologne-specific bin rules
• i18n/
  • translations.ts — All UI strings in EN/DE
  • useTranslation.ts — Hook: returns t() + lang
• screens/
  • ScannerScreen.tsx — Main barcode scanner
  • GuideScreen.tsx — Full bin guide reference
  • HistoryScreen.tsx — Last 50 scans
• services/
  • productService.ts — Open Food Facts API calls
  • rulesService.ts — Material inference + bin lookup
• store/
  • useAppStore.ts — Zustand store (city, lang, history)
• types/
  • index.ts — Shared TypeScript types

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Rules Engine

Flow: Barcode → Open Food Facts API → Material inference → City rules → Bin result

1. Send barcode to Open Food Facts API
2. Extract packaging/material tags
3. Map to material key (plastic_bottle, cardboard, etc.)
4. Lookup in active city's JSON file
5. Display bin type, color, emoji, tip

Fallback: unknown → Restmüll + "check packaging" note

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Add New City

1. Create src/data/rules/yourcity.json (copy berlin.json)
2. Add city to CITIES array in useAppStore.ts
3. Add require() in rulesService.ts
4. Submit PR

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Data Source

Open Food Facts — free, open product database. No API key needed.

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Roadmap

• Visual search (photo → bin)
• All 400 German Landkreise
• Bin collection calendar
• Recycling centre map
• Offline product cache

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Contributing

PRs welcome for:

• New city rules
• Rule corrections
• Translations (Turkish, Arabic, Ukrainian)

Open issue first for big changes.

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License

MIT — see LICENSE.

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