I bought five Tuya Power Monitoring Smart Plugs some time ago, paying $4.30 each delivered. They work as expected using the Tuya Smart App, but I would prefer to replace the firmware with something I am in control of.
Tuya Wifi Power Monitoring Smart Plug
The easiest would be to replace the firmware OTA (over the air). Otherwise, I would have to open the devices, solder wires to them, and flash a new open-source firmware onto them. Once the device is liberated, OTA firmware updates should be possible.
The plug contains a small Wifi-module which is marked CB2S and e524923, Unfortunately, these are NOT based on ESP devices so Tasmota cannot be installed.
A little googlin gave this:
- Youtube: Tuya WiFi Smart Plug – How to disassemble
- smartnydom.pl Forum: based on BK7231N chip, not ESP8266
- on the above forum it says the wifi-plug accepts esphome or openBK via tuya-cloudcutter without disassembly.
- Elektroda topic 4040624 [BK7231N/CB2S/BL0937] Wifi Smart Plug with Energy Measurement (RMC021)
- Elektroda topic 4016515 Exploring the Ultra-Affordable 4€ Smart Plug from AliExpress: A Deep Dive
- Elektroda topic 3887748 Tuya LSPA9 smart socket – teardown, OpenBeken flashing guide for CB2S, BL0942
- Schematic: elivco lspa9
- Datasheet: CB2S module
- Github: libretiny-eu/libretiny
- Github: openshwprojects/OpenBK7231T_App
- Github: arendst/Tasmota/discussions/17173 suggest to replace the CB2S/BK7231N with a TYWE2S/ESP-02S module to run tasmota.
Tuya Cloudcutter – install OpenSource firmware OTA
- Youtube: Tuya-Cloudcutter & ESPHome: How-To Guide w/ Home Assistant
- Github: Tuya-cloutcutter disconnects Tuya IoT devices from the cloud,
- How To Guide – Tuya CloudCutter with ESPHome LibreTiny
I followed the above guide, but unfortunately, I was not able to install new firmware OTA. I should make tuya-cloudcutter work on this device too, but I don’t even know where to start. I should probably start by reading:
- Elektroda topic 4021129 Extracting DpIDs for TUYA MCU devices
This will have to be a future rabbit hole.
If the Software is broken give it some Hardware
If I need to physically open up the devices to flash firmware using wires, I might just as well replace the WIFI-module with an ESP based version, and install Tasmota, which is what I use on most of my IoT modules.
I have ordered TYWE2S/ESP-02S on Aliexpress, $2.18 delivered, but I have seen them as cheap as $1.19 plus shipping, which will turn out cheaper if you order a number of modules. If this will work, the power monitoring smart plug would end up costing me $6.49 or 45 Danish-kr, and I would have some BK7231 SoC to play with, the rabbit hole will be waiting for me.
Next time I will install the new Brain and Install Tasmota
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