I'd like to make a beacon system for robots where the beacon will have some IR LEDs around it pulsing at some known frequency. The module that hooks up to the robot will have a few IR photostransistors (are photodiodes better?) to detect direction. I'm thinking I'll have an MSP430 as the brains for each and speak I2C or TTL to indicate direction on the robot side. How do I detect that specific frequency so I don't mistake sunlight, etc. as the signal? How sensitive would this be? Do I need really powerful LEDs? What are all the considerations?
I want something like a 1 way version of this pololu beacon except one way (although two way might be a good idea too).