This is a simple tutorial to create an EMF detector. You can use Arduino for this job, but is better use a microcontroller called Attiny85. It is possible program it throe the Arduino interface.
What is a Magnetic Field [from Wikipedia]
An electromagnetic field (also EMF or EM field) is a physical field produced by electrically charged objects. It affects the behavior of charged objects in the vicinity of the field. The electromagnetic field extends indefinitely throughout space and describes the electromagnetic interaction. It is one of the four fundamental forces of nature (the others are gravitation, weak interaction and strong interaction).
The field can be viewed as the combination of an electric field and a magnetic field. The electric field is produced by stationary charges, and the magnetic field by moving charges (currents); these two are often described as the sources of the field. The way in which charges and currents interact with the electromagnetic field is described by Maxwell’s equations and the Lorentz force law. From a classical perspective in the history of electromagnetism, the electromagnetic field can be regarded as a smooth, continuous field, propagated in a wavelike manner; whereas from the perspective of quantum field theory, the field is seen as quantized, being composed of individual particles.
The materials of this project are:
- Proto board
- Breadboard
- Attiny85 X 1
- Green leds X 2
- Yellow led X 1
- Red led X 1
- CR2025 Battery X 1
- CR2025 Battery case X 1
- (optional) 40 Ohm resistors for leds X 4
- 1 MOhm resistor for probe X 1
- Jumper wires
Many of these components are in this KIT
Step 1: The circuit
First step is create a circuit on the breadboard. Use a breadboard like in photo and try the circuit before solder it on proto board. After the test you can use a proto board to connect the attiny85 to leds and antenna.
Step 2: The Code
See the code also on GitHub: https://github.com/masteruan/Attiny85_EMF
// EMF Detector Attiny85 and 4 led v1.0
// 23.10.2015
// original code/project by Aaron ALAI – aaronalai1@gmail.com
// modified for use by Giovanni Gentile – giovanni@0lab.it
#define NUMREADINGS 15 // Number of readings
into sense Limit = 15; // Raise this num to decrease sensitivity int val = 0; into antenna = A2;
into LED[] = {2,0,1,3}; // After verify the position of red green and yellow leds
// Variables for smoothing
Read More: Attiny85 EMF detector