This project consists of the design and creation of a compact embedded device capable of measuring power output of aircraft engines. The aim is to simplify the measurement process and provide accurate data to the crew renovating the engine. The small device can be mounted directly inbetween the engine and the propeller, making it fast and easy to apply on any aircraft. The device can measure power output directly ont he propeller, and log all relevant data to an onboard storage device while also sending it over wireless communication to an Android application. This thesis focuses on the design process, and demonstrates the capabilities of the product by testing on a real aircaft engine. The device is built according to the latest technological requirements in embedded system design, contains a powerful microcontroller and a Li-Ion battery with adequate protection circuitry. The embedded software uses a state of the art embedded operating system running on an ARM based processor with a Cortex-M4 core.