{"NAME":"NX-SM400","GPIO":[0,0,0,17,134,132,0,0,130,52,21,0,0],"FLAG":0,"BASE":18}

For more accurate energy consumption measurements this device requires power monitoring calibration.

Recently, some smart plugs with the BR plug type started appearing on AliExpress

Usually, these products don’t have a specific model and make, since they are mostly Tuya whitelables. After searching alot, I’ve found Nanxin NX-SM400 which looks like this one.

Flash Tasmota

Since this model working with the Smart Life app, we know it uses a Tuya chip. To flash Tasmota, we need to us tuya-convert. There’s an excellent tutorial (in pt-BR) by Douglas Baptista that you can use.

Configuring Tasmota

Go to the device’s IP address > Configuration > Configure Other > Template

{"NAME":"NX-SM400","GPIO":[0,0,0,17,134,132,0,0,130,52,21,0,0],"FLAG":0,"BASE":18}

Just paste that line and check Activate

Teardown

To create the template, I had to open the plug up.

If you want to do that, you can use a hot air gun on the bottom part and a flat head screwdriver to force it open. It will probably damage the case a little bit and you will need to glue it shut.

The smart plug uses the TYWE2S Tuya chip, which is a ESP8285.

The power monitoring chip is the BL0937 It’s pins are connected like this:

BL0937	ESP8285
Pin 6 (CF)	GPIO 4
Pin 7 (CF1)	GPIO 5
Pin 8 (SEL)	GPIO 12

The switch and LEDs are on another PCB. They are connected like this:

PCB	ESP8285
Red LED	GPIO 14 (Same as Relay)
Blue LED	GPIO 13
Switch	GPIO 3 (Rx)

At last, the Relay is connected to the GPIO14 pin.

Pinout

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