The IoT sensor was developed to detect α-, β-, γ- and x- radiation. The IoT sensor provides many features including a large, high-resolution LCD display with background lights and many indicators. The IoT sensor has an internal data storage for up to 2000 data sets, which are saved either manually or automatically. Furthermore the IoT sensor is equipped with a Bluetooth interface to transfer the measured data in real-time to a computer. With the software that is included in the delivery, the data can then be further processed and reviewed. The IoT sensor stands out with its high accuracy and practical design. The radiation meter can be applied in the pharmaceutical industry, laboratories, power plants, quarries, the emergency services, metal industries, petroleum reservoirs, environmental protection etc.