In this master’s thesis, the concept of “Internet of Things” or IoT platform is explained through the making of device which measures the air quality, collects and processes data in real time, and displays it in a Web application. This device consists of a microcontroller board Wemos D1 Mini as it’s central unit, which is based on ESP8266 microchip. Wemos D1 Mini collects data from CCS811 and BME280 sensors. CCS811 is an air quality sensor which measures the quantity of particles in the air, and BME280 is an atmospheric sensor which measures three sizes: temperature, pressure and relative humidity. Connecting with the MQTT broker is made wireless via Wi-Fi network, using the MQTT protocol. The concept of IoT is explained, its importance and usage in industry. Wemos D1 Mini is described, as are the used sensors. The characteristics of Raspberry Pi mini computer are briefly stated. The functioning of the MQTT protocol and its usage are explained. The process of programming is explained for Wemos D1, Raspberry Pi, as is the process of configuring the MQTT broker.