InfraRed = gps ?

[Kevin Watson]

Originally Posted by mightywombat

ok. So you'd have one beacon tracking each of the different types by how often they recieve envelopes? How exactly are you going to figure out the distance from the emitter? Will the signal be recognizeably weaker the farther you get from it?

This is the sequence of events within the beacon state machine:

1) The type-0 beacon is allowed to flash for 1ms. As the carrier frequency is 40KHz, this means the LED will flash on and off 40 times.

2) A delay of 3.5ms where both LEDs are off. This allows reflections to die off before...

3) The type-1 beacon (on the other side of the field) is allowed to flash for 2ms, which means the LED will flash on and off 80 times.

4) Another 3.5ms delay is inserted where the LEDs aren't flashed before the state machine starts all over again at #1 above.

If you add up all of the periods (1ms + 3.5ms + 2ms +3.5ms), you'll see that the total time needed to flash the beacons is 10ms, which means the beacons flash at a 100Hz rate.

You can calculate your distance and angle to the beacon by using a little trig (exercise left to the student ).

-Kevin