Right (cheap) sender/receiver for beacon

Other Hardware Sensors
1

Hi,

I plan to build a becon finding robot. My questionis how to se up a good and cheap beacon and receiver pair.
One aproach would be to use my HC-sr004s.
http://forum.arduino.cc/index.php?topic=173414.0

I also have a pair of nrf24l01+. But with only a 1 bit "rssi" I think it is hardly usable. I would need to shield it extremely well from three sides. Not realistic .. I think.

Is there any other good and cheap method? IR is too short range I think. And too expensive if I want a wider beam.
I have a roomba virtual lighthouse. But I have no idea on how to detect it.

All suggetsions are welcome.

Thanks
Robert

2

the lighthouse puts out a continuous 500 HZ square wave.

3

Thanks for the info. Does this mean I need to look for a 500 hz IR sensor?
I don't remeber to have seen one. Only The 38 khz modulated sensors.

4

google for ' hacking roomba virtual lighthouse '
it comes up with interesting things like this:-
http://www.robotreviews.com/chat/viewtopic.php?f=4&t=16544

Does this mean I need to look for a 500 hz IR sensor?
I don't remeber to have seen one.

I doubt if you will find one the 30 to 42 KHz ones are used in TVs so there are lots of them about.
I suspect you will have to make one yourself.

5

I confused a virtual wall for a lighthouse. The 500 hz square wave came from a virtual wall, not lighthouse.
I detected the signal with a phototransistor going to my scope.