This high voltage device has been built because of several stories I have heard where spirits appeared to be able to interact
with electricity. As everyone knows, for every action, there is an equal and opposite reaction. If a spirit can be affected
by voltage -- as these anecdotes were reporting -- then they should also be able to affect it actively.
Here, the concept is a simple one. If the spirit is willing to cooperate, and if the device works, a yes or no response to questions will be the result, indicated by movement one way or the other on the meter. If that works, there is little reason to not be able to scale it down to keyboard level, and a spirit could then type -- onto a computer screen.
If the keyboard works, the concept could also work in a musical keyboard, so that a spirit with some ability to play piano or organ could play music thru it.