Wi-Fi Smart Switch
A Wi-Fi-controlled switch built around an ESP32-C3. It lets me control a regular wall switch from a phone while keeping the electronics hidden behind the existing switch.
Watch it working
Overview
A standard wall switch made controllable over Wi-Fi. An ESP32-C3 Super Mini and a relay sit behind the faceplate, powered by a phone charger. Typing the board's IP address into a phone browser opens a page with an on and off control.
Commercial smart switches mean replacing the faceplate. I wanted the switch to look exactly as it did before.
- Controlled from any phone on the same Wi-Fi
- No app, just the board's IP address in a browser
- Everything fits behind the original faceplate
- About ₦5,000 in parts
How it works
The setup is deliberately simple. A phone charger powers the ESP32-C3, the relay is wired to one of its pins, and the relay switches the light.
The firmware connects the board to Wi-Fi and serves a small web page at its IP address. Pressing on or off on that page switches the relay.
Challenges
Anything inside a wall switch is working at 240 V, so the first decision was how to get down to the 5 V the ESP32-C3 needs without building a mains power supply myself. An ordinary phone charger does exactly that: it is a sealed unit that converts the mains and keeps it isolated from the low voltage side. The relay is the only part that touches mains directly. The rest was fitting three parts into the space behind the faceplate.
Gallery
Build Details
| Controller | ESP32-C3 Super Mini |
|---|---|
| Switching | Relay module |
| Power | Phone charger, 240 V to 5 V |
| Control | Web page at the board's IP address |
| Parts | About ₦5,000 |