ELECTRIC CHARGE DETECTOR ECD-102
The ECD – 102 is an electronic version of the electroscope. Electroscopes are simple science instruments for measuring high voltage. However the ECD-102 can detect electrostatic potential of as little as one volt! The ECD-102 can detect the invisible fields of voltage which surround all electrified objects. Assuming spirits carry an electric charge of some sort, this device – in theory would detect them. The way it works is simple. The ECD-102 responds to the movement of positive (+) and negative (-) electric charge. When the approach of an negative charge is sensed, the LED turns off.
These work the way the old Epods did but with a large range.