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levoit-sprout

README.md

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Levoit Sprout - Custom Firmware (ESPHome)

Air purifier with 4 fan speeds. Unlike other Levoit models, the Sprout has two unique hardware features:

  • White noise — plays one of 15 built-in sounds stored as MP3s on the ESP32 flash (LittleFS assets partition). Volume and sound selection are controlled by the ESP32, not the MCU.
  • LED ring — decorative RGB light ring on the front, controllable in nightlight (static color + brightness) or breathing (pulsing) mode.

Uses the Vital flat-TLV protocol (CMD=02 00 55) as a base, with Sprout-specific extensions for the LED ring, white noise, PM sensors, and MCU async events.

Quick Facts

Item Value
Model Sprout
Tested MCU FW 1.0.5
ESP Module ESP32-D0WDR2-V3
Flash 8 MB
Fan Speeds 4
CADR (spec) 144.5 m³/h
Room Size 9-30 m²
ESPHome 2026.1.2+

Features

Shared with Vital

Feature Type Notes
Fan fan 4 speeds, presets: Manual / Auto
Auto Mode select Default / Quiet / Efficient
Auto Mode Room Size number m²
Auto Mode High Fan Time text_sensor Remaining high-speed runtime in efficient mode
Display switch Toggle LED display
Child Lock switch
PM2.5 sensor µg/m³
AQI sensor As reported by MCU
Current CADR sensor m³/h, updated every 5s
Filter Life Left sensor % remaining
Filter Low binary_sensor On when < 5%
Filter Lifetime number Configurable in months
Reset Filter Stats button Resets CADR/runtime counters
Timer number Run timer in minutes
MCU Version text_sensor
Error text_sensor "Ok" or "Sensor Error"

Sprout-specific

Air Quality Sensors (direct to ESP32)

Sensor Chip Interface Measures
Temperature + Humidity Sensirion SHT4x I2C °C / %RH. Also used to compensate SGP40 readings
VOC Index Sensirion SGP40 I2C 1–500 VOC index
CO2 Winsen MH-Z1911A UART or PWM True NDIR CO2, 400–5000 ppm. Mounted on carrier board "Baymax-CO2-Senser-V1.1SP2"

MCU - Fan / etc RX: GPIO23 TX: GPIO22

I2C - Sensirion SGP40 / Sensirion SHT4x GPIO14 - SCL GPIO27 - SDA

Uart MH-Z1911A Baud: 9600 RX: GPIO02 TX: GPIO15 or reverse?

Music GPIO:17/5/18/19 17 => data? 5=clock?/1Mhz 18=clock/32kHz 19= on/off

Via MCU (UART protocol)

Feature Type Notes
PM 1.0 sensor Raw count from PM sensor (tag 0x0C)
PM 10 sensor Raw count from PM sensor (tag 0x0D)
Fan RPM sensor Fan tachometer (tag 0x27)

ESP32-controlled

Feature Type Notes
LED Ring switch Decorative front LED ring on/off (restores nightlight mode)
Light Mode select Off / Nightlight / Breathing
LED Brightness number Nightlight brightness AND breathing max brightness (0–4095 LE16)
LED Color Temperature number Nightlight color temperature (0–255, default 58)
LED Brightness Min number Breathing mode minimum brightness (0–255)
LED Breathing Time number Breathing cycle duration in seconds (1–10)
White Noise switch Enable / disable white noise playback
White Noise Sound select Sound 01–15 (MP3/OGG stored in ESP32 flash — see note below about downloading all sounds)
White Noise Volume number Playback volume (0–255). Handled by ESP32, not MCU
Last MCU Event text_sensor Last async event from MCU (button press, white noise state change, cover)
Cover Open binary_sensor Filter cover/door open sensor

Protocol Notes

The Sprout uses the same Vital flat-TLV serial protocol. Additional Sprout commands:

CMD Direction Function
02 08 55 MCU→ESP Async events: tag01=button press/release, tag03=white noise state change {active, vol, sound}, tag04=cover open/close
02 0B 55 ESP→MCU Nightlight: tag01=on/off, tag02=color temp (0–255), tag03=LE16 brightness (0–4095)
02 0C 55 ESP→MCU Breathing: tag01=mode, tag02=cycle time (1–10s), tag03=LE16 max brightness, tag04=min brightness
02 07 55 ESP→MCU White noise: tag01={active, volume, sound_index} + constant trailer 03 03 05 08 F2
02 02 55 ESP→MCU White noise fan mode: payload 10 01 01 (enable) / 10 01 00 (disable)

Note: White noise volume and sound selection are handled entirely by the ESP32. The MCU only receives the final active/volume/sound state.

Teardown / Disassembly

TODO: add teardown steps and photos

Twist open the top head counter clockwize

Debug Header Pinout

TODO: add pinout and photos

Wiring New ESP

TODO: add wiring photos and pin mapping

Flash

Prerequisites

Connect to the debug header with a USB-UART adapter (3.3V TTL), crossing TX/RX:

  • Adapter TX → MCU RX
  • Adapter RX → MCU TX

Connect IO0 to GND before powering on to enter bootloader mode.

Backup Existing Firmware

esptool.py --no-stub --chip esp32 -b 460800 read_flash 0 0x800000 firmware-backup.bin

Extract audio assets (MP3s from LittleFS assets partition):

pip install littlefs-python
python extract_assets.py firmware-backup.bin
# output written to assets_extracted/

Important: Only 5 of the 15 white noise sounds are pre-loaded in flash. The rest must be downloaded via the original app before flashing. Before replacing the firmware:

  1. Open the original Levoit app → White Noise
  2. Add sounds 1–5 to the playlist and tap Save — the ESP32 will start downloading them
  3. Wait for the upload to finish, then add sounds 6–10 → Save
  4. Wait, then add sounds 11–15 → Save

Then re-dump the flash (read_flash 0 0x800000) — all 15 sounds will now be stored in the assets partition.

Audio Files

File Sound Source
100001.ogg Summer rain Pre-loaded
100002.mp3 Gentle sea wave Pre-loaded
100006.mp3 Insects chirp by the stream Pre-loaded
100009.mp3 Morning seaside Pre-loaded
1000012.mp3 Sound 12 (name TBD) Pre-loaded
others Remaining 10 sounds (names TBD) Downloaded from app
bgm.mp3 UI background music Pre-loaded
switch.mp3 Button click sound effect Pre-loaded

Configure

  1. Copy secrets-example.yaml → secrets.yaml and fill in your Wi-Fi and encryption key
  2. Check and update the UART pin assignments in levoit-sprout-c3.yaml
  3. Check the component README for UART pin mapping per board

Flash

esphome run levoit-sprout-esp32.yaml

ESPHome Web Builder / Dashboard

Use the pre-generated builder yaml to flash without a local clone — all config is inlined, no !include or packages needed:

File Board
levoit-sprout-builder.yaml original ESP32

Upload to the ESPHome web builder or paste into the ESPHome dashboard. Regenerate with .\make-builder-yaml.ps1 from the devices/ folder.

Restore Original Firmware

esptool erase_flash
esptool write_flash 0x00 firmware-backup.bin