OpenCarbon

Most buildings waste tons of energy because they have no idea when rooms are being used. I'm building a simple sensor system that tracks CO₂ levels, temperature, and humidity—so buildings can actually see where they're wasting electricity and heating.

Each sensor costs about €20 to build (ESP32 microcontroller + CO₂ sensor) and covers a classroom-sized room. The data goes to a dashboard where you can see everything in real-time. I've been running this in my university for 4 months and we found out the ventilation system was running full blast in empty rooms—wasting 30% of the energy budget.

Professional systems cost €500-2000 per room and you're stuck with their software. Mine is completely open source—anyone can build it, customize it, and host it themselves. No monthly fees, no vendor controlling your data.

Everything will be on GitHub: hardware schematics, firmware code, dashboard software, and step-by-step build guides. If you want to modify it for your needs—different sensors, new features—you can.

Schools, small offices, and co-working spaces can't afford expensive monitoring systems. But they're the ones who could benefit most—many are in older buildings with inefficient HVAC.

If this helps them cut energy use by 15-20%, that's real money saved and real emissions reduced. A small school saving 15% on heating could be €2000-3000 per year. Scale that across hundreds of buildings and it actually matters.

Right now I'm hand-soldering everything on breadboards. That's fine for testing but not for other people to actually use. I need €850 to:

• Manufacture proper circuit boards (€300) — 50 units so they're reliable and easy to assemble
• Send beta kits to 10 testers (€200) — schools, co-working spaces, and offices across Europe
• Write documentation (€200) — build guides, setup instructions, troubleshooting help
• Cloud testing (€150) — make sure it works at scale with many sensors