ESPHome for Tuya SK20 WiFi Nebula Light

This repository contains an esphome configuration file for flashing esphome to Tuya SK20 nebula lights. Thanks to the amazing work of a lot of other people no disassembly or soldering is required. You can simply jailbreak the device using your laptop and flash ESPhome (or any other LibreTiny / WB3S-compatible firmware).

References

The following repositories, projects and tools helped a lot in jailbreaking my nebula light:

• teardown, research and pictures: https://github.com/kireque/esphome_nebula_light
• basic/unfinished esphome config for included uC: https://github.com/fonix232/esphome_nebula_light
• exploit to flash tuya devices without disassembly: https://github.com/tuya-cloudcutter/tuya-cloudcutter
• esphome support for BK7231T devices: https://docs.libretiny.eu/
• tutorial on flashing esphome: https://docs.libretiny.eu/docs/flashing/tools/cloudcutter/
• discussion regarding the esphome configuration for this nebula device: kireque/esphome_nebula_light#8

Pictures

Basic instructions

This guide assumes you have a Linux computer and some basic terminal knowledge. The used tools also have some prerequisites like python, docker and plattform.io Make sure you have the esphome CLI installed

Configure your secrets by creating the following secrets.yaml file:

wifi_ssid: "<your SSID>"
wifi_password: "<your wifi password>"
wifi_fallback_password: "<some random password>"
ota_password: "<some random password>"
api_password: "<your home assistant api password>"

Then, build and flash the image using the following commands:

$ wget https://raw.githubusercontent.com/M4GNV5/esphome-SK20-Nebula-Light/master/recommended_base.yaml
$ esphome compile recommended_base.yaml
$ git clone https://github.com/tuya-cloudcutter/tuya-cloudcutter
$ cp ./.esphome/build/nebula/.pioenvs/nebula/image_bk7231t_app.ota.ug.bin tuya-cloudcutter/custom-firmware/star_nebula_bk7231t.ota.ug.bin
$ sudo ./tuya-cloudcutter.sh

The last program will guide you through the jailbreaking procedure, asking you for the following information. You will also have to long press the device button for a few seconds twice until it is slow blinking (WiFi AP mode):

• (2) Flash 3rd Party Firmware
• By manufacturer/device name
• Tuya Generic
• SK20 Smart Star Projector
• 1.1.2 - BK7231T / oem_bk7231t_light3_laser_nanxin
• star_nebula_bk7231t.ota.ug.bin

The nebula light should now connect to your Wifi and/or host its own fallback AP.