The Internet of Things (IoT) and Industry 4.0 is evolving and has a high demand for reliable electronics. This work contributes to the creation of user-friendly and robust applications for the IoT. The topic is the development of a radio communication system regarding the requirements for the end user and concerning a high flexibility of the application. The result is a core board featuring USB programming capability to flash the user application, USB power delivery (USB-PD) for battery charging, a fuel gauge, as well as a Microcontroller Unit (MCU), and a Radio Frequency (RF) transceiver. This core board can be combined with different sensor or actor shields to increase the flexibility and re-usability. To ensure proper functionality of all crucial design blocks they are analyzed and simulated with state of the art techniques. First, the system requirements are laid out and explained in detail. The implementation that satisfies these requirements is presented and necessary simulations are discussed, the results are presented. To complete the work, measurements of the system are shown and compared with the simulation.