Smart Plug - Case Study
The client required a smart plug designed to seamlessly extend their existing portfolio of smart home appliances and meet the growing consumer demand for energy-efficient home automation. The device needed to feature a sleek, minimalist aesthetic, and a compact form factor while leveraging the ESP32 microcontroller for native Wi-Fi Mesh connectivity. A core requirement was a future-proof system architecture, ensuring that both the hardware and firmware were engineered to support easy scalability and the seamless addition of new devices into the client’s expanding smart ecosystem.
Project Context
To deliver on these commercial goals, the smart plug was developed to accurately monitor real-time power consumption, execute localized scheduling, and safely toggle standard mains power. Real-time power consumption monitoring is the process of continuously tracking the energy usage of connected devices. A foundational requirement of the project was an adaptive, future-proof system architecture. The ESP32 microcontroller was selected as the core processing unit from the outset, chosen for its dual-core performance, native Wi-Fi capabilities, and built-in support for mesh networking. While the initial development phases utilized off-the-shelf ESP32 hardware to validate basic relay functionality and power telemetry, both the firmware framework and the custom PCB were deliberately engineered to support future expansion.
“The ESP32 microcontroller provides robust dual-core performance and native Wi-Fi capabilities essential for smart home integration.” The development process followed a strict, phased lifecycle designed to de-risk production and optimize space constraints. It began with proof-of-concept functional validation on development boards before transitioning to a highly compact custom PCB design tailored to fit the tight limitations of the plug’s physical enclosure.
Project Context
To deliver on these commercial goals, the smart plug was developed to accurately monitor real-time power consumption, execute localized scheduling, and safely toggle standard mains power. Real-time power consumption monitoring is the process of continuously tracking the energy usage of connected devices. A foundational requirement of the project was an adaptive, future-proof system architecture. The ESP32 microcontroller was selected as the core processing unit from the outset, chosen for its dual-core performance, native Wi-Fi capabilities, and built-in support for mesh networking. While the initial development phases utilized off-the-shelf ESP32 hardware to validate basic relay functionality and power telemetry, both the firmware framework and the custom PCB were deliberately engineered to support future expansion.
“The ESP32 microcontroller provides robust dual-core performance and native Wi-Fi capabilities essential for smart home integration.” The development process followed a strict, phased lifecycle designed to de-risk production and optimize space constraints. It began with proof-of-concept functional validation on development boards before transitioning to a highly compact custom PCB design tailored to fit the tight limitations of the plug’s physical enclosure.
Hardware Stack with Custom PCB Layoutk
Each of the following components was carefully selected and integrated into a custom PCB layout engineered to fit within the tight physical constraints of the plug’s consumer enclosure.
Firmware Stack
System Implementation
Product development track complete the smart plug’s implementation followed a strict, standalone lifecycle designed to de-risk high-voltage integration and optimize extreme space constraints. The lifecycle commenced with an autonomous Proof-of-Concept (PoC) phase utilizing off-the-shelf ESP32 hardware to safely isolate and validate basic relay actuation and real-time power telemetry. This allowed the firmware framework to be built from scratch as a separate, dedicated codebase, ensuring the smart plug operates as a self-sufficient edge device capable of independent execution before ever interacting with the wider network.
The smart plug required workflow focused on safe AC/DC mains power toggling, localized energy calculation, and aggressive thermal profiling under load. “Safe AC/DC mains power toggling is critical for preventing electrical hazards and ensuring reliable operation.” The custom PCB layout was engineered from the ground up to fit within the highly restrictive, minimalist boundaries of the plug’s physical consumer enclosure while strictly maintaining necessary electrical safety boundaries.
Time Estimates
The following table outlines the estimated development hours across each project milestone, from initial analysis through to physical validation of the hardware platform. Firmware estimates reflect the complexity of building on top of the ESP32 microcontroller, particularly the time required to implement and tune the native Wi-Fi Mesh stack for reliable node integration within the broader smart home ecosystem.
| Stage | Min h | Max h | |
|---|---|---|---|
|
Component selection |
8 |
14 |
|
|
Schematic drawing |
14 |
20 |
|
|
Component package drawing |
8 |
12 |
|
|
PCB routing |
16 |
24 |
|
|
Production files & component ordering |
8 |
12 |
|
|
Assembly & Hardware Testing |
22 |
36 |
|
|
Total Hardware time |
74 |
116 |
|
|
Wifi communication (Node setup & BLE provisioning) |
40 |
60 |
|
|
ESP32 WiFi Mesh communication (Node mesh integration) |
48 |
72 |
|
|
ESP32 WiFi Mesh communication (Node mesh integration) |
48 |
72 |
|
|
Cloud MQTT broker communication (done within the Gateway project) |
32 |
48 |
|
|
Mobile App communication via MQTT broker |
224 |
256 |
|
|
Bussiness logic – Schedules |
104 |
136 |
|
|
Total Firmware time |
448 |
572 |
|
|
Quality Assurance |
50 |
60 |
|
|
Project Management |
50 |
60 |
|
|
Total project time |
622 |
808 |
Note: To the final total project estimated time might be added up to 15% of time for risk assessment.
