Temperature and humidity are important variables to determine changes in the state of a substance or object. By knowing the change in temperature, we can know the direction of the physical change. Therefore, it is very important to monitor changes in temperature and humidity in a system. To fulfill various needs, various sensors were developed. Therefore, it is very important to monitor changes in temperature and humidity in a system. To fulfill various needs, various sensors were developed. In this study, the authors use the NodeMCU microcontroller development board as a control center that connects to wifi communication. DHT11 temperature and humidity sensor which functions as a temperature gauge of 4 objects in turn, namely the temperature of the ice cubes, temperature of water heated by electric water heater and temperature of electric solder neck. Measurements are made in contact with a maximum distance of 0.4 cm from the object. The results of the DHT11 temperature sensor readings will be continued by sending real time information every second with units of ° C which can be seen using the visual basic net application, which is desktop-based for monitoring data with communication via wifi that is running well and stable. Temperature and humidity measurement data can be stored through an online database, namely firebase. Because sensor data is stored by NodeMCU to the Firebase Real-time Database, the VB Application can access it anytime and anywhere

Keywords : Sensor DHT11, NodeMCU, Visual Basic Net, Firebase, Wiif