I'd like to build a ghost detector. I'm only just beginning the design stage, and thought I'd reach out for some suggestions.
Receiver: I'm planning to end up with a handheld device with an analog backlit meter, which illuminates when the house lights turn off. The meter will display the present of a particular frequency. I have lots of old FPGA projects which I can modify to use as the radio. Or maybe an Arduino for the logic and ADC interface to the meter? I haven't used an Arduino before.
Transmitter: Now to generate the ghosts... The "ghosts" should be some RF signal or frequency which can readily be received in a common household. While I have a good bit of experience in building transceivers, they have always been over coax or fiber. I'm not familiar with all the FCC codes for OTA, so I'd rather stick to detecting "ghosts" (ambient signals) which already exist. Which leads me to my questions:
Q1 Which frequency should I look for? The lower the better, to keep costs down. The project is for my kids - I'd like for them to be able to walk around and find the presences of "ghosts" coming in and out of range. So the signal should be readily available, but intermittent (attenuation by the home's structure, perhaps). Would 60 Hz work?
Q2 I think it might be fun to have the house lights flicker when the meter hits a high mark. To do this, I would have to transmit after all, but the signal could be very low power - just enough to trigger a remotely controlled wall socket. Surely the socket is a COTS device, but if any of you have done this before, or know of a suitable unit, I'd appreciate the information.
Any other suggestions or ideas would be greatly appreciated.
Note I'm not looking for real ghosts here. It's just a toy for the kids.