Open-source, low-cost device for visualizing static magnetic field components at 0.25 T and 3 T

We present a low-cost (<$17 USD per channel), open-source, and scalable prototype for visualizing the three-axis static magnetic field components up to 3 T based on the GaAs Hall effect technology. The prototype showed accuracy and stability on the bench and accurately measured field values in a 0.25 T electromagnet and a 3 T MRI scanner.