Scrap Setu: Fair Prices and Easy Pickups for Household Scrap and E-Waste
Scrap Setu connects households, small scrap collectors and recyclers with fair, live prices, nearest-collector pickups and an AI photo scan. We built it in four days for Environmental Hacks.
The problem
Every Indian city has a scrap chain that few people talk about. A household sells old newspapers and bottles to a local collector. The collector sells to a bigger dealer, who sells to a bigger one, and finally the material reaches a recycler. Every step takes a cut, and the small collector, who does the hardest work, often accepts whatever price is offered.
E-waste is worse. Old phones, chargers and laptops sit in drawers or end up in the general trash, because households do not know what they are worth or who will take them.
We chose the Waste and Energy track because it names these problems directly: recycling, e-waste and informal recyclers.
The idea
Setu (सेतु) means bridge, and that is the whole product. Scrap Setu connects households, small collectors and large recyclers, and shows everyone the same rates.
HouseholdsBook a pickup, see a listed rate per kg, and photograph an item to find out what it is and how it could be reused.
CollectorsSee pickup requests near them, nearest first, with distance and directions, and sell through the platform to recyclers with steady demand.
AdminsUpdate live rates. The change shows up for everyone within a minute.
What we built
- Pickup booking. Customers add scrap types and weights and get an instant price estimate. A collector accepts the job and the customer is notified.
- Nearest collector. Customers can share their location. Collectors see only a spot rounded to about 1 km until they accept, so browsing never reveals a home address.
- Photo scan. Take a photo and AI identifies the material and the closest price category. If it is not sure, it says so and lets the person choose by hand.
- Live pricing. Rates cover paper, plastic, metal and glass, plus e-waste: laptops, circuit boards, batteries, TVs and monitors. An admin can edit rates or apply a market trend in percent, and up and down arrows show on the price tables.
- Trust features. Customers can cancel a pickup, and rate the collector from 1 to 5 stars once it is done.
- Impact on the dashboard. Kilograms recycled, estimated CO₂ saved, money earned and the collector's rating.
- Saved in a database. Users, pickups, prices, notifications, and the About and Contact pages.
- Google sign-in for people who do not want another password.
The stack
- Backend: Python with FastAPI, and SQLite through SQLAlchemy
- Frontend: plain HTML, CSS and JavaScript with no framework, so it loads quickly on budget phones
- AI scan: Gemini vision, returning structured JSON
- Maps: Leaflet with OpenStreetMap
- AWS: [Add which AWS open source tool or AWS service you used, and how]
What fought back
- The photo scanner kept giving wrong answers. Our first version asked the AI for free text and read it line by line. A small formatting change in the reply broke it, and the app quietly fell back to guessing from colours. We switched to a strict JSON answer and, more importantly, made the app admit when it is unsure instead of inventing a result. A wrong answer costs a collector real money.
- Privacy versus usefulness. Collectors need to know a request is nearby, but we cannot hand out exact home locations. Everyone browsing sees a rounded location, and only the collector who accepts the job gets the exact spot.
- Two collectors, one job. If two people tap Accept at the same moment, only one should win. We moved the check into a single database update so a job can never be double-booked.
- The camera does not work everywhere. Browsers block the live camera on plain http, which is how most people test on a phone. We added a Phone camera button that opens the native camera instead.
- Prices that change. Rates had to be editable without redeploying, so we moved them into the database with a trend multiplier.
What's next
Scaling the Ideas we have discussed: payments inside the app, Hindi and regional language versions, route planning for collectors, and partnerships with recyclers.
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