Levoit Mini - Custom PCB & ESPHome Firmware

Custom PCB, 3D-printed parts, and ESPHome-based firmware to add smart home integration to the Levoit Mini Air Purifier without destroying the original device.

Levoit Mini Custom Build

Features

Non-Destructive Modification – Fully reversible; original PCB is completely bypassed, not removed
Home Assistant Integration – Native fan integration with multiple speed presets
- 3 speeds: 33%, 66%, 100%
- Manual, Sleep (25% speed), and Auto (requires PM2.5 sensor for AQI feedback)
- Configurable filter lifetime (1-12 months based on usage/pollution)
Performance Monitoring
- Real-time fan speed and CFM (cubic feet per minute)
- Average CFM calculation
- Filter replacement reminders
Compact & Custom – Custom PCB with built-in components; 3D-printed enclosure parts for seamless integration

Home Assistant Dashboard - Controls Home Assistant Dashboard - Diagnostics

Usage Instructions

Click Button One time, for at least 1/4s to turn on and cycle speeds.

Double click Button quickly, to turn on and cycle preset modes (Manual, Auto, Sleep).

Long Press Button, 2.5s+ to turn off the device.

Filter can be resetted via HomeAssistant integration

Build instructions

Disassembly

Remove the Air Filter
Remove the 4 Screws
User a long Screwdriver or similar item to carfully lift the top, by pushing inwards and down, after the first one or two are open, continue from the outside
Unplug the original PCB

BOM

Xiao Seeed Studio ESP32S3
LCD - 0.91 Inch OLED Display I2C SSD1306
Level Shifter - 3.3 / 5v Bidirectional
DC-DC Stepdown Converter, MP1584EN 22mm x 17mm x 4mm
Button, 12 mm x 12 mm x 7.3 mm
Sockets and Connectors
- JST-XH 2.5, 2pin and 4pin
- JST-PH 2.0, 2pin and 4pin
Wires
Custom PCB
3D Printed parts

Custom PCB

PCB Assembly

I used poor man’s smd soldering, but using pin header will also work - Add some solder to the bad with holes and then place the part on top and add solder to the top hole until it melts down, start with two opposite corners. Ensure connection is fine with Multimeter.

3D Printed Parts

Button & LCD Assembly

Wire the LCD and button together using JST-XH connectors as shown in schematics
Insert the button into the button holder and slide into place; secure with hot glue or super glue
Glue the LCD into its mounting bracket using hot glue—recommend powering on during gluing to verify correct positioning

Device Assembly

Insert the replacement top housing (larger custom-printed part) and connect the new PCB to the device’s internal connectors:
Cross-reference the original connector positions and replicate the same connections:
Connect the LCD and button assembly to the main PCB
Position the button/LCD module into the device: the button should face the Levoit logo; slight twisting motion helps snap it into place
Verification: Device should respond to button presses and LCD should display correctly