A 100-bed student hostel was haemorrhaging electricity costs because students routinely left ACs running in empty rooms. There was no way for supervisors to monitor or control 25 individual AC units without physically walking every floor. We designed and deployed a smart IoT plugin system with a real-time mobile app and supervisor dashboard — giving complete visibility and remote control over every AC in the building.
Challenges we faced
- Students habitually leaving ACs on when leaving for college — rooms cooling empty spaces for 8–10 hours daily
- No centralised control: supervisor had to physically walk 4 floors to switch off individual units, covering 25 rooms
- Existing AC units were standard split ACs with IR remotes only — no WiFi or smart capability built in
- Hostel runs on a shared electrical circuit — needed per-room power monitoring, not just building-level metering
- Students using high cooling settings (16°C) overnight — no temperature governance or scheduling possible
- Supervisor needed to monitor from a single screen which rooms had AC on and for how long, to identify repeat offenders
Our solution
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Smart IR Plugin Installation
Installed WiFi-enabled IR blaster plugins (Tuya-compatible smart plugs with integrated IR emitters) in all 25 rooms. Each device connects to the hostel's WiFi network and can both transmit IR commands to the AC and measure real-time power consumption via built-in energy monitoring. No modifications to the existing AC units were required.
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Tuya Cloud Integration & API Layer
Connected all 25 devices to Tuya IoT Cloud using their OpenAPI. Built a Node.js middleware layer that abstracts device commands into a clean REST API: /ac/{roomId}/power, /ac/{roomId}/temperature, /ac/all/status. Added WebSocket support for real-time state push to the dashboard.
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Supervisor Mobile App (iOS & Android)
Built a React Native app for hostel supervisors. Home screen shows a live floor plan grid of all 25 rooms — green (AC off), orange (AC on, room occupied), red (AC on, room likely empty based on scheduled class times). Supervisor can tap any room to view current temperature, power draw (watts), and runtime. One-tap off, schedule off, or set temperature cap directly from the app.
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Web Dashboard for Management
Built a Next.js web dashboard for the hostel owner. Features: daily/weekly power consumption per room, cost estimation based on current electricity tariff, auto-off scheduling (e.g. all ACs off between 9am–5pm on weekdays), temperature governance (minimum 22°C enforced across all units), and alert system for ACs running more than 2 hours in likely-empty rooms.
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Automation Rules Engine
Implemented a rules engine: ACs auto-switch off if power draw drops below threshold (indicating room is empty — no human body heat load). Class timetable integration automatically flags rooms as likely-empty during college hours. Supervisors receive push notifications for policy violations. Monthly reports auto-emailed to hostel owner.
Outcome
Electricity bills dropped 38% in the first billing cycle — saving the hostel approximately ₹18,000/month. Supervisors now manage all 25 ACs from a single screen instead of physical floor walks. Average AC runtime per room dropped from 14 hours/day to 8.5 hours/day. The temperature governance feature eliminated the 16°C overnight complaints from the facility below. The system has been running for 7 months without a single device offline.
Tech & tools used
- Tuya IoT Cloud
- React Native
- Next.js
- Node.js
- WebSockets
- REST API
- Smart IR Plugins
- Energy Monitoring
- Push Notifications