A Low-Cost, Hand-Held Device for Measuring AC Low Magnetic Field

This article presents the design of a low-cost and hand-held device for measuring low magnetic fields over a wide frequency band, i.e., 50 Hz-30 kHz. The device primarily consists of a self-designed detector coil and field display unit comprising dedicated signal conditioning circuitry, analog-to-digital converter (ADC), microcontroller, and organic light-emitting diode (OLED) screen. The coil senses the variation in the magnetic field in terms of voltage signal, which is displayed on the screen after suitable hardware and software processing. The validation of the developed device was performed with a Helmholtz coil. In measuring magnetic field values from 10 to 2000 mG, the device depicted exceptional accuracy, sensitivity, linearity, and frequency response parameters. In comparison to similar available magnetometers, the developed device showed a remarkable closeness in measurement. The developed device can become an affordable and reliable means for monitoring magnetic fields that have significant applications in electromagnetic interference/electromagnetic compatibility (EMI/EMC) measurements, healthcare, etc.