Hardware needed:

DS18B20(Dallas) sensor is a high precision sensor in a stainless steel tube that is also waterproof. The pinout is simple, 3 wires: black – ground, red – power and yellow for data.

Soldering the wires is fairly simple.  Covering it with tape is ok for keeping the wires in place.


Black – G;

Red – 5V;

Yellow – D3;



Uploading Tasmota

For getting Tasmota firmware on the board we will use nodemcu-flasher. Download Tasmota binary (release page) and nodemcu-flasher(64 or 32).

Connect the microusb cable to WeMos/NodeMCU and open nodeMCU-flasher. In the first tab (Operation) select the COM port for your device. In the second tab (Config) select the Tasmota .bin file.

And lets not forget about the “Advanced” tab:

Click on “Flash” and get your phone ready .

When the upload is done, the board will create an access point for you to connect to. Search for a “sonoff-…” open wifi network and connect to it. Open your favorite browser and type


You will get a wifi setup page as shown below. Enter your wifi network details and click save.

For further configuration you will have to find your device on your network. You can scan the entire network or take a look at the dhcp list on your router.

In the next tutorial you will learn how to connect this device to Node-RED.