Have you ever had issues with electromagnetic interference (EMI)? Well now you can track down the source with this simple DIY, which lets you make your EMI detector using an Arduino. Now you can hunt for the culprit without spending a lot of money.
This DIY uses a light level meter. You start by replacing the light dependent resistor with a hight value resistor and a piece of wire as an aerial antenna. You replace the LEDs. The principle behind it, is that the Arduino senses the voltage on pin A5 and higher the voltage, more LEDs light up.
You can get the schematic designs in the PDFs attached in the link and see the circuit diagrams and code. You mainly need LEDs and resistors apart from the Arduino connector strip, battery connector and a hook up wire. You can get the exact specifications from the link given below. Use a perforated board to make the connections as shown in the link below. Solder everything together and you are good to go.
Now you can move around your EMI detector to the suspects and the one which is causing the interference will make the LEDs light up.