This magnetic field sensor app measures and displays a graph of Magnetic Field (µT) vs. Time (s) that in x, y, and/or z dimensions, as well as total magnitude. By accessing settings, data can also be displayed with a digital read-out. Total magnitude magnetic field strength can be recorded and exported in an e-mail or through Google Drive as a .csv attachment using a comma or a semicolon as a delimiter. Click on settings to plot data against elapsed time or clock time, to change the plot line thickness, or to change data collection rate. A brief tutorial upon start-up gives an overview of how to use the app. The magnetic field sensor can measure the background magnetic field of the earth and be used to check for the presence of permanent magnets or electromagnetic fields. Within the classroom, the magnetometer can be used to determine the inverse-square law for a "point source" magnet, to determine the strength of a field produced by a solenoid, or to measure the frequency of objects with magnetic variations, such as audio speakers or magnetic plate stirrers. Permissions Explained: android.permission.WRITE_EXTERNAL_STORAGE: A csv file is created and modified on the phone's internal memory. If you have any questions, comments, or would like to see modifications/updates, please email me at [email protected]