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User avatar
By Liam Aps
#86724 Not sure if this has been posted before... Soldering required for this fix.
I found this to be the simplest fix for me.

1) Remove STC15F104W chip
2) Short pins 6 and 7 on pad where STC15F104W was removed
3) In Tasmota firmware, configure ESP-01 (ESP8266) RX=Relay1

April 9-2019
User avatar
By cgmckeever
#87769 Appears many have found this thread.

Some observations:

- There appear to be at least 3 different versions of this board.
--- I can confirm the one labeled v3 works out of the box sending the serial commands referenced in this thread
--- There is one labeled HW-655 that seems to work out of the box (unconfirmed)

As others have stated, with some modification, these will work. There are at least 3 different modifications listed in this thread that are close. All revolve around removing the microcontroller (

I have success:
- removing the 15F104 MicroController
- Connect v3.3 to GPIO0 with a 10kOhm resistor
- Connect pin 7 of the 15F104 to GPIO0
- NOT removing R4 as others have
- [url="
"]Use Pin 0 high/low for relay[/url]
- Disclaimer: I dont know if this thing will blow up or not

Who knows. Sucks that this board is such a pain in the ass. Re-iterate however, the v3 boards works
User avatar
By cgmckeever
#87781 First off, I wanted to thank @rickgtx and @pilol34 both their contributions to this thread was intense.

Second, for future explorers down this rabbit hole. This thread more or less has everything needed to get running. Either through the above mentioned MCU flash, or a bunch of different modifications to the board. Its all in here, you'll just need to read through this several times.

I have tried to document this Hopefully it helps as a good jump off point.
User avatar
By avilchez
pilol34 wrote:Hello;

I too was very disappointed when buying this module. When I connected it for the first time, it is flashing as shown on this link ( and it was not responding at any of my orders.

After a rechere on the web, I found on the website of the manufacturer ... &p_id=1204
this note:
For this wifi relay module, because there are some counterfeit on other sales platform. So if the LED on-board (D2) are blink constantly (I guess the reason is the STC15F104W have not been programmed), it means the module were not produced in our factory, maybe you need to contact the seller directly. Best regards!

And then I realized that I had to program the module to solve the problem (I not found the original firmware).

Here are the results of my work after several days of work.

ATTENTION, The programming and or the alteration is under your resposability because it is always possible to do an error or mishandling that may endanger the module.

1. An FTDI232 interface is required to connect the USB protector to the module's RX TX pins. Here we use an interface to 5V.

2. Software is required to program the module's STC15F104W. Here I used stc-isp.exe (v6.86E) found on the site (Hey yes, I work under windows).

3. Create a program and compile it in .HEX format. Here I create a .asm program that I compile thanks to the AS31.exe utility from Paul's 8051 Tools at

4.The program must be transferred to the module. It is necessary to think to cross the cables TX RX and one does not branch 5V power supply.

With the programe STC-ISP.exe we load the proramme .hex, we set the clock at 11.0592 MHz, and press the button DOWNLOAD / PROGRAM, Connect the 5V power supply of the module and wait until the transfert is finished.

5. In the COM Helper tab, test the module with commands A0 01 01 A2 and A0 01 00 A1 in HEX-Mode.

6. If the led lights up but the relay does not work, it will alter the module by swapping the resistors R3 and R4. This is probably the most delicate operation you will have to do.

7. Afterwards, follow the setup for the ESP-01 module.

To speed up your work, I give you my version of the program in .HEX format Which will save you from making the item 3. This program is transmitted as-is and without guarantee. I have not done advanced testing and it is not optimized.

I added to the program relay status reading commands.

B0 01 01 B2 -> Reading relay in text format ("ON" and "OFF" ending with a linefeed).
B0 01 00 B1 -> Relay reading in binary format (00 = ON and 01 = OFF).

B0 00 01 B1 -> Reading the firmware version in text format ending with a linefeed.

You just have to copy and paste into a text file with the extension .hex.

File: LcWifiRelayUartV1_0_9600_11mhz.hex

Code: Select all:0300000002017387

Now it's up to you to do the rest.

Good luck.

Please, can you post the .asm code?