Open Source ESP32 Smart Light Switch Cover

Idea 250,111

I’ve been thinking about an easier way to make any light switch “smart” — without rewiring the wall or replacing the existing switch. My idea: an open-source ESP32-powered light-switch cover that mechanically toggles the switch you already have.

The Concept

The device is a replacement faceplate that mounts over a traditional rocker or toggle light switch. Inside, an ESP32 board controls a small servo or geared motor that physically flips the switch up or down. Instead of cutting into high-voltage wiring, it uses tiny “leakage-current” prongs to harvest a small amount of power directly from the line running to the switch. That’s enough to keep the ESP32 active or charge a small onboard capacitor or battery.

The ESP32 then connects over Wi-Fi or Bluetooth to Home Assistant, Google Home, or similar platforms, letting you control the mechanical switch remotely while maintaining the manual function of the switch itself.

Why This Matters

Most smart switches require you to:

Replace the whole wall switch.
Deal with high-voltage wiring.
Depend on proprietary firmware or cloud services.

This cover keeps the mechanical safety and tactile feedback of the original switch, but adds modern control. It’s also open source, meaning the hardware files, firmware, and 3D-printable enclosure can all be shared and modified by anyone.

How It Works (Planned Architecture)

Power harvesting: Two small conductive prongs tap the switch terminals to gather micro-current.
Microcontroller: An ESP32 handles Wi-Fi, Bluetooth, and MQTT or HTTP communication with your smart-home hub.
Motion system: A low-profile servo motor or geared stepper flips the switch physically.
3D-printed cover: Fits standard North American switch plates; designed for easy installation and removal.
Software integration: Simple MQTT firmware with OTA updates, and an optional web dashboard for calibration.

Goals for the Project

Publish all CAD files, STL models, and schematics on GitHub.
Develop an open firmware compatible with ESPHome and Home Assistant.
Build a small community of contributors who can improve design and share ideas (better power harvesting, miniaturized motor, etc.).

Future Add-Ons

Capacitive or touch-free control overlay.
Local manual override button or gesture sensor.
Battery-assisted Wi-Fi version with solar charging.
Modular front plates for different switch types.

Get Involved

If this idea resonates with you — whether you’re into hardware hacking, IoT, or open-source automation — I’d love your feedback and collaboration.

I’ll post schematics, 3D models, and ESPHome YAML soon. Together we can make a truly open, retrofit-friendly smart-switch solution.

Comments and ideas welcome below — how would you power or mount your version?