How do make a device that bleeps when a secondary (remote) device moves 10 metres away?

Question

I'm trying to build an electronic gadget that bleeps when another remote device moves out of a pre fixed range, ie 5- 10 metres, is this possible? What would the main components be for this?

In an omni direction.

Answer 1

Unlinke dansinger61, I am assuming you are worried about losing a child in a busy area.

If you put "child out of distance monitor" into a search engine, you will get plenty of commercially available units.

If you are interested in the problem simply as a problem to solve, I would reckon you need a weak FM transmitter with a not very sensitive FM receiver which will alarm if the received signal strength drops below a certain level.

Answer 2

I'm guessing you're trying to solve the "lost remote" problem. This is feasible, but not practical. The remote would need to be continuously operational to provide the feedback (either IR or RF) required for the base station to know it had moved out of range. That continuous operation would drain the batteries too quickly. People don't want a remote control that they have to replace the batteries in every week (or more).

Answer 3

Yeah its possible, Their are two ways that you can do it. One is using infrared signals or Two use radio waves. I would Probably go with infrared. You can probably go up to radioshack and some of them have these selves that pull out and it has alot of electronic parts that you can pick out. But yeah hope i could help some.

Answer 4

Take a piece of string 5 (or 10) meters long ....

..... (you can guess that rest)