Let's Make Robots!

Cheap yet relative accurate signal sensors

Thanks for visiting the nuthouse!
Anyhow, I'm trying to figure out a relatively cheap, yet accurate, distance-sensative sensor.

So, the end question is, does anyone know of a sensor type that can be mounted on an arm,
that moves from 0 degrees to 180, 6 inches apart, to detect my location by something I'm carrying?

-From what I've read, the standard RFID chips don't usually even cover 5 feet.
-I've tried bluetooth, but the sensor strength fluctuates too much for a clear reading,
unless you're right on top of it, and anything in the room pretty much returns around "10".
-I know there are other RFID chips out there, but I don't want to buy one, just to find it's accuracy lacks between a certain key range... so I hope someone may be able to tell me a reasonably priced chip I can carry,
that it can tell from just moving 6" if I'm far left or right.

An IR Sensor/Beacon combo IS a consideration, but I'd like something that could find me through people.
If you know of a cheap yet reliable set for that though, I'd like that recommendation, as well.
Something simple I can just connect to the analog input pins on my Picaxe,
yet is barely noticable to others if I'm wearing it, hopefully.


You can skip this part if you understand, but I included it for a better visual of what I need.
Let's say I have a slow rolling ball with the required transmitter in it.
With a remote control firetruck, with the "ladder" on a servero, holding the sensor, moving left and right, looking for the ball, within a range of 2ft to feet to maybe down a hallway or across the room. What sensor would be the most accurate way to have it find that ball, considering interference of people walking and the like? 

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Unfortunately, I never learned trig lol.
Though I'm naturally math-inclined... I just never learned how to do equations.

What you said helps, though I wanted to clarify on something there:
I don't actually need to know the distance, I was just wanting the range more or less, so I could figure out which way to go by moving the sensor left and right 6" apart, to find what direction the beacon is in... unless I use IR, which would just rotate to look.
Also, using the 2 antennas and finding my exact angle... turning that precisely on the fly...
I honestly think it a bit above my current ability level at this point...
but it's definately something to look forward to try in the future, once I'm better!

For the oddbot IR eye, when you said it can't look through a crowd, does that mean less than other IRs for some reason, or are you just saying that other people can get in the way? Because I can have it keep moving forward in the direction of the last place the beacon was seen, rotating to look for it until it finds it... which can help in areas with corners and people, right?
Which also seems to be a little more in my current ability level, to be honest. $30 is a bit steep for me too.

How do you suppose I could get an accurate angle in Linux/Debbian?
That would probably be my much preferred method, if you had experience or concepts there?
All  I could get was a reasing, -6 to -11 from moving close to it in my living room.
So I don't think moving it 6" would make much of a difference to measure distance... >_< 

Is there an actual method to get bluetooth angle?