AbstractIn this study, we offer a low-cost laboratory practice for an introductory physics class laboratory for students of any grade level in science and engineering. This practice, in which a mobile phone (iOS, Android, or Windows) is used in conjunction with mini magnets (similar to what's found on refrigerator doors), a rule, paper, and a free application (app) which has to be downloaded and installed to measure magnetic fields by using smartphone's magnetic field sensor or magnetometer, was very well received by our pupils. This practice is completely free. The major aim of the exercise is for students to discover the influence of component x of the magnetic field produced by various magnets. We discover that the magnetic field's dependence on distance takes the form _____, which is perfectly compatible with the theoretical analysis. The second purpose is to compute the magnetic field found in various types of household electronic devices. Keywords: Measurement of magnetic field u (MaFiU).....