Smart Building Controller
A compact, BLE-enabled building automation controller for a UK PropTech startup, designed from schematic through CE certification and into volume production within six months.
Key Design Features
Overview
Our client needed a compact wireless controller to retrofit into commercial building HVAC systems. The hardware had to be cost-optimised for volume, CE-marked, and ready for production within six months.
The Challenge
The existing approach used off-the-shelf modules that were too large and too expensive for the target BOM cost. The system also needed BLE for local configuration and MQTT over WiFi for cloud reporting, both from a single, compact PCB.
Our Approach
- Selected an ESP32-S3 SoC as the main processor, combining WiFi and BLE in a single certified module to drop BOM cost and shrink the board.
- Designed custom power management circuitry supporting both mains and PoE input, with LiPo backup for graceful shutdown on power loss.
- Wrote firmware in C using the ESP-IDF framework, with a custom MQTT client and a BLE provisioning stack tailored to the client's commissioning workflow.
- Managed the CE compliance pathway end-to-end, including pre-compliance testing, formal lab submission, and documentation.
Outcome
Final PCB footprint
BOM cost reduction vs. module-based prototype
CE mark achieved on initial test submission
Units shipped in first production run, on schedule