I had two of these chips from different vendors in the "My Choice" section, both labeled as DIY Mini Smart Switch. Like others mentioned, I used the below pins to solder since it came with 1.3.10 firmware; I wasnt able to extract GPIO pin layout with the tool, the software failed there, but writing was fine. Below layout worked for me:
- Pair/Toggle All Pin on P23
- WiFi LED on P26
- TglChannelToggle (channel 1) on P6
- Relay (channel 1) on P7
I accidentally desoldered a capacitor (https://www.elektroda.com/rtvforum/topic4056582.html) but havent run into issues so far
Hello, i have this module and i'm trying to flash it using serial.
I connected GND to S1 and other 4 pins as described on >>20797138 , but I can't backup the flash using bk_writer1.60.
I set the right port and 115k baud, but when i power on the device I have
Time:11.105s
Speed of Reading:115200bps
reading flash:0x00000000...FAILED
What am I missing?
If I keep the CEN down it doesen't start to download the flash.
And next, can you give me a guide regarding how and what to download to the cpu?
At the end I will try to install espHome, BK7231N should be supported.
I've also stopped using CEN over time. It always works without CEN, and in extreme cases, when it doesn't want to reset, I just temporary short the disconnected 3.3V wire from the WiFI module side with ground and it helps. (NOTE: do not confuse and do not short the 3.3V from power supply with ground, obviously!)
And another tip is to use S1 instead of soldering gnd. At the end only 3 pins have to be soldered (idk if it's possible to use capacitors pins to connect 3.3V or maybe > 4V before voltage reductor) to reduce the number of small pins to solder
Hey there, i just bought a couple of similar devices with kind of the same configurations and pinouts but the model differs.
is it worth it to upload some pictures and firmware dumps? if so, i'll gladly upload them here or wherever its needed.
The discussion centers on the DIY Mini Smart Switch 2-way from UNSH, model SS8839-16A-W, based on the BK7231N chip, sold on AliExpress. The device features a custom PCB without a standard Tuya module, facilitating direct firmware flashing. Users share detailed pinouts for various versions, including GPIO assignments for relay control, buttons, LEDs, and toggle functions. Flashing is commonly performed using tuya-cloudcutter or serial methods with USB-UART adapters (e.g., CP2102), often without requiring the CEN pin. Firmware versions such as Tuya V1.3.10 are noted, with OpenBeken (OpenBK) firmware successfully uploaded to enable custom control and power metering support (notably with BL0942 and BL0937 chips). PowerSave mode (PowerSave 1) is recommended to prevent device crashes and overheating. Multiple PCB revisions exist, some with power monitoring and others without, differing in component layout and pin assignments. Users report challenges with deep sleep functionality and flashing stability, resolved by correct pin configuration and startup commands. JSON configuration templates for OpenBK are shared, including pin mappings and commands. Additional hardware details include the presence of varistors, NTC resistors replacing fusible resistors, and rectifier components (E1J). Flashing guides and tools such as BK7231GUIFlashTool and YouTube tutorials are referenced for assistance. The community emphasizes careful handling due to high voltage and the ease of opening the device for soldering and flashing. Summary generated by the language model.
