The MDT USB25103 is a three-axis digital magnetometer that is intended for the measurement of magnetic fields near the probe tip at frequencies less than 250 Hz. The MDT USB25103 combines three orthogonal magnetic field sensors with plug-and-play USB data acquisition electronics and software to provide a three-axis digital magnetometer system in a simple form factor. It is designed such that the user may use it directly combined with the proprietary MDT graphical user interface (GUI), controlled with a terminal emulator program, or integrated into the user’s custom written program. The GUI can be run on a desktop computer, a notebook, or a Windows tablet. Additionally, the probe electronics may be reprogrammed by the user using freely available open source Arduino development tools. The MDT USB Magnetometer is thus a complete development tool that allows a user a simple means for experimenting with magnetic sensors, sensor applications, and developing sensor algorithms.