This is a short teardown of the DIY Mini Smart Switch 2-way from UNSH model SS8839-16A-W based on BK7231N.
It uses custom PCB, so no Tuya module to replace, already bought one
Basic Information
Brand: UNSH - Tuya
Model: DIY Smart Switch SS8839-16A-W
Chip: BK7231N on board
Seller:
AliExpress 16A Tuya WiFi Smart Switch 2-way
Photos
The switch is very easy to open so i wont go into details, but remember, this device it's using
high voltage, so make sure it's not connected to the mains.
Flashing-Uploading OpenBeken firmware
Used tuya-cloudcutter to flash OpenBK (had to setup in SmartLife/Tuya app - after first flash device did not connect to cloudcutterflash AP)
Followed this instructions
tuya-cloudcutter INSTRUCTIONS.md
and video
Flash OTA using tuya-cloudcutter
> By firmware version and name
> ~ Mini Smart Switch
> 1.2.1 - BK7231N / oem_bk7231n_control_switch
OpenBK7231N_UG_1.15.648.bin (CCtr flash)
Requirements:
RPi to install
GitHub tuya-cloudcutter
Firmware
OpenBK7231N_UG_1.15.648.bin
Router/AccesPoint for temporary local cloudcutterfalsh AP
some patience and persistence
Device could not connect to cloudcutterflash AP after reboot,
so I needed to create a "second" cloudcutterflash AP on spare Router with internet connection as stated in
Note: of
INSTRUCTIONS.md.
Had to disable WiFi on RPi - tuya-cloudcutter
After that it was possible to enter WiFi credentials thru Tuya app.
Turned off "second AP", enabled tuya-cloudcutter and the process of flashing OpenBeken continued.
Pin settings for this device.
TglChanOnTgl - 6 - PWM0 - ch0
Rel - 8 - PWM1 - ch0
Btn - 23 - ADC3 - ch0
LED - 26 - PWM5 - ch0
Simple test environment
! This smart switch connects power line N-out and S1 together that makes it unsafe for use other than with the classic wall switch !
I would like to thank everyone who enabled this to work
Elektroda and OpenBeken Team
tuya-cloudcutter Team
and all of enthusiast who are posting and filming their work
Payed 3,63 € For
UNSH Tuya 16A Tuya WiFi Smart Switch 2-way and 2,18 € form ESP-02S module witch I could not use.
with alternatives
~12 € is the price for Athom 3 Way Relay for ESPHome if buying 3 pieces with shipping
or
9~13€ Sonoff MiniR2 from local store
It was worth for the experience, tinkering, flashing, rebooting
Comments
Thank you for submitting the teardown. As usually with this kind of the device, I would like you to enable the BK-specific power save function: PowerSave 1 in startup command (use backlog for multiple... [Read more]
This is a short teardown of the same seller and the same order and the same package DIY Mini Smart Switch 2-way from UNSH model SS8839-16A-W based on BK7231N. Basic Information Brand: UNSH... [Read more]
This is a short teardown of the same seller and the same order and the different package Smart Mini Switch 2-way from UNSH model EZB-WBZS1H16N-A V1.0 based on BK7231N. Basic Information Brand:... [Read more]
https://obrazki.elektroda.pl/6164833800_1694987789_thumb.jpg https://obrazki.elektroda.pl/5837675600_1694987963_thumb.jpg I opened 2 new Mini Smart Switches and they seem to be this version... [Read more]
So you have the same board as me? https://obrazki.elektroda.pl/2023531600_1694988973_thumb.jpg Here is GND (black) and 3.3V (white): https://obrazki.elektroda.pl/8756638100_1694988926_thumb.jpg... [Read more]
hahah that was blazing fast!! thanks a lot!!! [Read more]
Same device with same pins but it came with tuya V1.3.10 firmware, so I couldn't use tuya cloudcutter. But It worked with serial port: https://obrazki.elektroda.pl/1455238100_1698961621_thumb.jpg ... [Read more]
Those devices are so easily openable that for me the "soldering" method is actually easier than the cloudcutter. Of course, in case of devices like light bulbs, cloudcutter may be preferrable, but for... [Read more]
Very similar device, but different pads. Flashed with CP2102 USB UART. Ground soldering is easier at the switch however P1 pad also working (I used the switch). Important: CP2102 don't provide enough... [Read more]
Thanks, can you include JSON template from the OBK Web App? [Read more]
If you asked me then I edited my comment :) As I can see you are the main developer - thank your for your efforts! [Read more]
To be precise, the thing you attached is a Tuya JSON format , not OBK JSON format, but luckily I can easily convert it with our tool: https://openbekeniot.github.io/webapp/templateImporter.html { ... [Read more]
Did you also find the CEN pad? [Read more]
@chrizzz to the best of my knowledge no CEN is required. I flashed hundreds of devices via wires so far and I am not using CEN for that. [Read more]
@pkaczmarek2 that's strange, I couldn't get a connection - do you have a how to which I should use? Just to start again with another source? [Read more]
Here are our guides: https://www.youtube.com/@elektrodacom See this playlist: https://www.youtube.com/watch?v=L6d42IMGhHw&list=PLzbXEc2ebpH0CZDbczAXT94BuSGrd_GoM If you really need CEN, then here... [Read more]
Hi, I bought a few pieces of those devices on AliExpress "Choice" (less than 2€) I found that there is 2 different PCBs ( for the moment :-) ) Here's the pinout i have: https://obrazki.el... [Read more]
Is there any way to tell which is which from the outside? I don't know, maybe one is 10A version and second 16A? [Read more]
Unfortunately no. From the outside they are exactly the same (and 16A for both) https://obrazki.elektroda.pl/2342231300_1705135842_thumb.jpg [Read more]