“A simple to build, but very sensitive electromagnetic field detector.
This is a simple device capable of detecting very weak electromagnetic fields. The relative field intensity is displayed on the LCD display and at the same time are given a buzzer sound signalization and LED light signalization. In this case the sensor is a plain copper wire, with a 1.5mm diameter, but you can use any piece of wire or metal tile. Sensitivity can be adjusted via code, and also by changing the value of the resistor connected between A0 and grounding. With the help of a switch, one of the two values of the resistor is selected, and thus the degree of sensitivity of the device. So we can easily calibrate it, by comparing it to a recalibrated industrial device.”