You could make a simple 3-part product that does just that. You place them in various parts of your house, they calibrate together (play an inaudible sound and

You could make a simple 3-part product that does just that. You place them in various parts of your house, they calibrate together (play an inaudible sound and measure delay), and then have them manufacture traffic to your target device to figure out where it is. I imagine they could be somewhat close together (e.g. same room), which makes setup way easy. I can't imagine it would be very difficult to make, provided small Wi-Fi capable devices are sufficient, it just needs some work on the details.