Gosund SP111 – Tasmota

Today we are going to cover a simple case – Tasmotize very popular smart plug with ESP. The main advantage of this smart plug is power measurement as well as max power up to 3450W (declared by the manufacturer).

Although you may find a lot of tutorials on how to upload Tasmota to this device using Tuya-Convert script, they are not working anymore since plugs produced after November 2020 are delivered with unsupported firmware. Fortunately, there is still ESP8285 on board which can be flashed with Tasmota but we have to disassembly the device and use USB-UART converter. Even though it may sound difficult, I highly recommend trying, it’s not easy to break it and there is no need for soldering – I flashed 4 devices in this way without any problems.

What do we need:

• Thin and long cross screwdriver. I use Xiaomi WOWSTICK 1F+ which I really recommend.
• USB-UART converter. I use this but most of converters should work fine.
• 5 goldpins male <-> female.
• USB cable (not necessery, however it’s easier to operate not to close to the computer).
• Computer with Windows or Linux/macOS with python 3.

Dissasembly:

First, we need to open the plug by unscrewing the screw inside the grounding hole. You don’t have to take the screw out. I did it once and had a lot of problems with putting it back inside.

After unscrewing it should be fairly easy to take off the transparent lid. During the opening, try not to lose a small metal tube as well as a violet sponge from plus insides. I recommend putting it inside the plug just after opening like in the below photos.

Connecting gold pins and BOOT mode:

Now is the tricky part. We need to connect gold pins to the small holes on the PCB. They are so small that it’s impossible to put them inside. I know that some Smart Home enthusiasts try soldering or sharpening gold pins, however, I have not so steady hand to manipulate with soldering iron inside and I’m too lazy to sharper gold pins.

Let’s prepare 5 pieces of adhesive tape and take off plastic from two gold pins because they are too big.

Now point gold pin directly into holes, and use adhesive tape to all gold pins, one by one, in order to steady them in place as well as to prevent short circuits.

The last step is to connect the other end of gold pins to UART converter. Remember, that TX pin on the device connects with RX pin on the converter, and RX with TX. Do not connect GPIO 0 anywhere. Instead, touch the GND pin on PCB while connecting the converter to your PC. Just after providing current, you will see the red LED which indicates that power has been delivered. You can now take GPIO 0 gold pin and the red LED should be slightly dimmed which indicates you are in boot mode. That’s correct.

Flashing process:

1. Ensure you are in BOOT mode. See above.
2. Download Tasmotizer from https://github.com/tasmota/tasmotizer , either Windows exacutable or install tasmotizer using PIP on macOS or Linux. My additional advice when using PIP is to do this in venv:

mkdir ~/tasmotizer
cd ~/tasmotizer
python3 -m venv venv
source venv/bin/activate
pip3 install --upgrade pip wheel
pip3 install tasmotizer
python3 -m tasmotizer.py

The above steps are only for macOS and Linux cases. If you use Windows just open downloaded exe file.

3. Choose COM port which represents your converter.

4. Choose release button and you will get the newest tasmota available on the list. Use tasmota.bin.

5. Click tasmotize and wait until the process is finished. If there is a problem with connection you are either not in BOOT mode or your cable are not connected properly. Ensure gold pins touches the holes and are connected properly to converter (remember about RX<->TX case!).

6. Use send config to send your WiFi settings. You can also reboot your device, connect to tasmota’s AP and set the configuration there.

7. Add the proper configuration by going to Configuration -> Configure Other and provide this:

{"NAME":"Gosund SP111 v1.1","GPIO":[56,0,158,0,132,134,0,0,131,17,0,21,0],"FLAG":0,"BASE":45}

8. Your smart plug should reconnect using the new template. You will notice that by seeing power measurements as well as blue LED shining bright. If you don’t see power measurements (they are all zeros), it means you need to use another template for another revision. I’ve provided here rev. 1.1. Another revision can be found here.

9. You can assembly your socket back and configure other options to suit your needs. The Violet sponge should be placed on the ESP and metal tube inside the screw hole.

Please let me know in the comments section if it helps 🙂