Location sensor?

[ahkumm]

Imagine the situation,a 4 year old boy wearing a device which can tell the parents where he is in when he got lost with the parents in a crowded hypermart...and the parents hav a device with them telling them where their son is...should i use IR or radio frequencies or maybe some other alternative choice?

 

[kinjalgp]

Try using RF communication, modules for which are readily available in the market. Infrared won't work because Light always travlels in staright x line and so there should be line-of-sight between parents and child for the system to work. Whereas Radio Frequency does not require Line-Of-Sight.

Kinjal

 

[kinjalgp]

Hey! but RF will just indicate the vicinity of the child to the parents and not his direction. So the solution to this may be GPS (Global Position System) which is very complex and advanced technique.

 

[ahkumm]

RF transmittion sounds pretty easy...but does electronic compass helps in this situation to locate the child? i just need to know the direction in the same level...and i am pretty sure i won't use GPS....

 

[kinjalgp]

I haven't worked with Electronic Compass. May be you can give it a try!

Or try searching for RF signal tracer circuits/projects. This thing does the same as you want. When you move in the direction of the RF source (RF source is carried by the child) the audio output from the tracer goes on increasing and vice versa. You might have seen such type of thing in old movies (70's and 80's). At that time it was very common.


Kinjal

 

[Crofty]

:idea: Use RF. Limit its range to match the distance you want it to trigger at. Arrange so that when the child is 'out of range' ie: its stopped receiving the RF signal pulses from the parents TX, make the childs receiver trigger a loud peizo alarm sounder. This should help pin-point the child by auditory means. RF direction finding would be be impractical.

Steve

 

[Sebi]

I know the sport, called "fox hunting". The "hunter" have a receiver with adjustable gain and a Yagi aerial. The "fox" is a hidden transmitter.
Also well known method for animal following.