Short Range Distance Tracking Device

Hey Everyone,

I am trying to build a small tracking device that will flash or beep faster or louder the closer to the object being tracked. I was hoping to be able to do this within a household or around a small property, so maybe a 25m range thereabouts. Could anyone point me in the right direction with the circuitry needed for the easiest way to build such a device??

No such device could be built would be reliable enough for absolute identification of the location of the target in the area specified. You could track if the device was in that 25 meter range, but even that wouldn't be 100%, but to track it's specific location within that 25 meter range would require a complex network of sensors and would still not be 100% reliable.

What is this for?

I"m thinking animal tracking?

Using one way RF to derive distance can be done with multiple receiving nodes, if you can measure the distance in time of flight and triangulate. Not easy for 25 metres.

Two way RF is a lot easier, you "ping" back and forth hundreds of times between the two transcievers and can then derive distance from the cumulated time of flights - fixed times.

One way can be done if you have 2 signals of differing propagation speeds, like transmit an RF pulse and a sound pulse together, and derive distance from the time difference.

Assuming sound pulses would annoy your animal, you could use an infrared pulse transmitted, and two infrared receivers that detect angular position, then derive distance and position from triangulation.