Hello!

First, thanks for your help in the past, cos all of your instructions / support / help IS very useful to a high school student.

Now, I've got another problem:

I'm making a soccer robot for the RoboCupJunior(mentioned many many times).

Now I need a IR sensor, which use a PHOTODIODE to receive the IR light, and through an op-amp(LM386) -> a comparator(LM339) -> 89C52's INT pin.

Can anyone suggest a circuit / sensor / method / data about the IR sensor?

Also, I want to know more about the RoboCupJunior, and sensors commonly used in the robot.

Here is another question:
Can anyone give me some data about the "Compass sensor"(the sensor which can change the direction, 'the angle from the North' into voltage).

THX AGAIN

Stanley Lio