Project Overview
FoogleTech designed and delivered a full Proof of Concept for a Smart Switch System — a retrofit IoT solution that converts any existing physical wall switch into a smart switch without rewiring. The system uses an ESP32-WROOM-32 Communicator Hub connected to the cloud via Wi-Fi and MQTT, while individual ESP32-C3 Smart Switch Nodes attach to physical switches and communicate via BLE 5.0 GATT. A mobile app (React Native / Flutter) provides user control. Deliverables included POC hardware for both the Communicator and Switch Node, plus full PCB designs.
The Engineering Challenge
- BLE connection limits: ESP32 BLE stack supports a maximum of 9 GATT connections (1 peripheral + 8 central) due to 512KB SRAM constraints — limiting the number of switch nodes per hub without architectural workarounds.
- BLE range in real buildings: 2.4GHz signals suffer ~3dB attenuation per wall and ~20dB in dense environments, reducing standard BLE Class 2 range to ~10m line-of-sight — insufficient for multi-room deployments.
- Coin cell power constraints: CR2032 batteries (220mAh, 10–15Ω internal resistance) suffer voltage drops below ESP32's 2.43V brownout threshold during motor inrush current spikes of 100–150mA.
- Wi-Fi reconnection delays: ESP32 Wi-Fi stack reconnection takes 3–8s, with DHCP renewal adding 1–2s and MQTT session restoration adding a further 2–5s — unacceptable for responsive smart switch control.
- Motor alignment precision: Mechanical tolerance stack-up of ±2mm across components and switch actuator position variance of ±1.5mm between manufacturers required a flexible, field-calibratable mounting solution.
Our Solution
- Implemented BLE connection pooling with priority queuing — using advertisement scanning for discovery and establishing GATT connections only during active communication, with a roadmap to BLE Mesh using ESP32-C6 (Thread/Matter).
- Deployed BLE 5.x Coded PHY (125kbps/500kbps) for 4× range extension, external 2.4GHz ceramic antennas (3dBi gain), and RSSI-based adaptive power control (0dBm to +20dBm) to overcome building attenuation.
- Resolved power constraints with a 470µF low-ESR tantalum capacitor bank and PWM motor soft-start (duty cycle ramp 0→100% over 50ms). Alternative path: 14500 Li-ion (2600mAh) with TPS63060 buck-boost converter (96% efficiency).
- Implemented Wi-Fi credential caching in NVS, MQTT persistent sessions (CleanSession=false, 24hr expiry), and exponential backoff reconnection (1s, 2s, 4s, 8s, max 30s) to minimise downtime during network interruptions.
- Designed parametric TPU enclosures with adjustable mounting bosses and a servo-controlled actuator with Hall sensor position feedback, plus a field calibration routine accessible through the mobile app.
- Delivered POC of Communicator Hub (ESP32-WROOM-32D), POC of Smart Switch Node (ESP32-C3-MINI-1), and complete PCB designs for both units — with full hardware test specifications covering power, RF, mechanical, and protocol tests.
Results & Outcomes
- Communicator Hub POC delivered: ESP32-WROOM-32D, dual-core 240MHz, BLE 5.0 + Wi-Fi 802.11 b/g/n
- Smart Switch Node POC delivered: ESP32-C3-MINI-1, cost-optimised RISC-V, BLE 5.0, low-power design
- Full PCB designs for both Communicator and Switch Node units
- MQTT v3.1.1 over Wi-Fi + BLE 5.0 GATT communication stack fully implemented
- Hardware test specifications: power & performance, RF & connectivity, mechanical & environmental
- Software test plan: BLE security validation, MQTT message integrity, command latency, concurrent operation
Why Smart Switch System Chose FoogleTech Software
FoogleTech Software is a specialist engineering company with over a decade of expertise in AI, embedded systems, IoT, and full-stack software development — serving product teams and enterprises across Smart Home & Consumer Electronics and beyond. Our engineers don't just write code — they understand the domain, the constraints, and the real-world pressures that ship deadlines create. For Smart Switch System, that meant deploying a pre-vetted team with direct experience in ESP32, BLE 5.0, MQTT, reducing ramp-up time from months to days and delivering production-quality work from the first sprint.
Every FoogleTech engagement starts with a structured discovery phase, follows a disciplined agile delivery model with daily engineering syncs, and ends with complete documentation handover — so your in-house team owns the outcome. No black boxes, no lock-in.