Hah, this was quite the experience! Not necessarily all in a good way, but a memorable experience nonetheless.
First impressions were a bit rough. For one, call me paranoid, but I'm always a bit reluctant to give out location information and other such data, and two, I had no idea the game was meant to be played on the phone only: my attempts to play it on computer just had it error out for location permissions, not giving me any sort of direction to change devices. It may seem obvious, but I was quite confused for a good few minutes.
Anyway, eventually I sorted everything out and got my own little ghost detector on my phone! It didn't seem to be doing any that special except barking out random garbly words now and then, but I was of the impression that there must be some sort of cool AR puzzle game at play here: maybe if I get the readings up to 100 or so, it'll give me a clear ghostly message that I need to use the symbols on the phone to decipher which will point me to some sort of location/website which I then solve using yadda yadda yadda. So, I set forth into the neighborhood!
Eventually though some hot and cold deduction, I was able to get my ghost detector all the way up to 99.9, which seemed like the highest it could get! Unfortunately, all that I encountered was a fire hydrant: no ghosts, no special message, no puzzle, no nuffin'. None of the random words that were popping up during my walk seemed to have any sort of significant pattern or spooky message either. I suppose this is accurately recreating toys of old, but it didn't make it any less disappointing.
So yeah, a bit let-down, but nevertheless I admire your creativity with this and hope you continue to experiment: last year's phone adventure game was great, for example!