This study aims to develop a smart belt that can be used to monitor elderly activities at home by integrating Multi-Modal Sensors (MMS) and the Internet of Things (IoT). The MMS used in this study to collect elderly information is the IMU sensor, vibration sensor, push button, and ESP32 to process IoT data. Furthermore, the IoT platform used to transmit elderly information data from the smart belt to the family smartphone is Blynk. In this study, the smart belt can monitor the activities of the elderly when walking, sitting, lying down, and sleeping. After that, the smart belt can provide warning alerts when the elderly carry out abnormal activities at home. The results of this study show that the smart belt can monitor the activities of the elderly when walking, sitting, lying down, sleeping, and warning alerts on the family smartphone based on the integration of MMS and IoT.