Fine dust monitoring system based on Internet of Things<bold> </bold>

In this paper, we propose to measure and monitor the fine dust (PM2.5) indoor. Also, using the app of the smart phone which is the monitoring device users are not constrained to time and place, IoT (Internet of Things) technology, which is one of the 4th industrial technologies is used to measure indoor and airborne fine dusts. And IoT devices (Fine dust sensors) and microcontroller, which is an embedded system are configured in hardware to precisely measure and collect data on fine dusts, A wireless transceiver device such as Wi-fi was used to transmit the collected fine dust data to the smartphone. In addition, IoT requires low-power, lightweight and accurate message delivery important and a more advanced message protocol is needed. Therefore, the protocols mainly used for IoT are MQTT (Message Queue Telemetry Transport) and CoAP (Constrained Application Protocol). The data transmission methods of these two protocols are TCP (Transmission Control Protocol) and UDP (User Datagram Protocol), The MQTT protocol which is superior in reliability was applied to the monitoring technology in this study<bold> </bold>