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Residential IoT
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Residential IoTIoT Middleware & Smart Home
NestCool — Smart Home AC Control
A custom IoT middleware layer that bridges Google Nest thermostats with existing CoolMasterNet AC infrastructure — enabling full thermostat-driven control of every AC unit in the home.
Project Snapshot
Project Type
IoT Middleware & Smart Home
Technology Stack
7
Technologies used
Project Brief
Project Overview
The customer was already using Google Home and Nest devices throughout their home but their installed AC units weren't supported by the Nest thermostat out of the box — no native integration, no official workaround, and replacing the ACs wasn't an option.
Fusion Softtech built NestCool — a Raspberry Pi running a Python-based middleware service that acts as the intelligent connector, listening for every thermostat change from Google Nest and instantly forwarding the right command to CoolMasterNet, which in turn controls the ACs.
Fusion Softtech built NestCool — a Raspberry Pi running a Python-based middleware service that acts as the intelligent connector, listening for every thermostat change from Google Nest and instantly forwarding the right command to CoolMasterNet, which in turn controls the ACs.
Context
Client & Business Background
Client Profile
A homeowner with an established Google Home and Nest smart home setup, looking to extend thermostat control to existing AC units that lacked native Nest compatibility.
Business Need
The customer needed a custom integration that would make their existing, unsupported AC units respond to their Google Nest thermostat — without replacing any hardware and without manual intervention.
Highlights
Key Capabilities
Real-time Nest thermostat event listenerCommand translation for all AC modes (cool, heat, fan, auto)Always-on systemd service with auto-start on rebootSelf-healing fault tolerance for network and API interruptionsSecure authenticated connections to Google Nest API and CoolMasterNetStructured logging for full command history and diagnostics
Process
Delivery Scope
Execution flow from design to launch readiness.
Architecture design for Raspberry Pi-based IoT middleware
Python middleware service development and integration
Google Nest API integration with real-time event handling
CoolMasterNet command protocol mapping and implementation
Systemd service configuration for always-on, auto-start operation
Fault tolerance, recovery logic, and structured logging implementation
On-site deployment and reliability validation
Engineering
Technical Execution
Engineering approach used to deliver reliability and performance.
Built a continuously running Python service on Raspberry Pi capturing every Nest thermostat event in real time
Designed a command translation layer mapping Nest events to CoolMasterNet's control protocol across all AC modes
Integrated Google Nest API and CoolMasterNet with secure authentication and clean error handling
Configured systemd for automatic service start on reboot, enabling fully unattended 24/7 operation
Implemented recovery logic handling network drops, API timeouts, and unexpected device states without manual action
Built structured logging to provide the customer with full command history and easy issue diagnostics
Stack
Technology Stack
PythonRaspberry PiGoogle Nest APICoolMasterNetREST APIsSystemdStructured Logging
Results
Impact Delivered
- Full Nest control — all home ACs manageable directly from the Google Nest thermostat
- No hardware replaced — existing AC units and CoolMasterNet kept entirely intact
- Truly hands-free — always-on, self-recovering service with zero day-to-day management
- Unified smart home — ACs fully integrated into the customer's Google Home ecosystem
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