eTesla 1.0

This application utilizes data from the phone’s internal compass to measure magnetic field variations induced by nearby metals or electromagnetic emissions from various sources such as high-voltage power lines, transformers, electric motors, and certain household appliances like microwave ovens.

The measurement units are expressed in Tesla (T) and microtesla (µT), with the latter being named after Nikola Tesla (1856-1943), the inventor of the Tesla coil and developer of the alternating current motor. Normal earth magnetic field levels typically range from 20 to 40 µT.

High magnetic fields can reach approximately 200 µT when near speakers, and in environments with strong electromagnetic sources such as electric motors, levels can exceed 300 µT. Exposure to such intense fields may potentially damage sensitive devices like credit cards or mechanical watches.

If the phone has been subjected to a high magnetic field, recalibration may be necessary. This can be achieved by shaking the device until the readings return to a normal range.

The app allows users to set an alarm threshold with a slider control; when this threshold is exceeded, the display turns red and the device vibrates as a warning.

In conclusion, it is advisable to avoid strong magnetic fields whenever possible—identify their location and maintain a safe distance to prevent potential damage or interference.