[gnormhurst]

Originally Posted by supergrover

We used the code from kevin.org (navigate) and we can't find what the distance should be between the two IR sensors. We want to use this for our autonomous mode, but we don't know how to make it work.

First, Kevin's approach uses four sensors -- two on each of two "trackers" that are hobby servos. Here are some pictures of how Kevin built his.

We mounted our two trackers on each side of our robot, about as far apart as we could (28-30"). Think of this: If you want to estimate the distance to the beacon, you can use the difference in the tracker pointing direction of the two trackers. But if the trackers are close together, that difference will be very small.

Kevin has a good FAQ about some of the problems people have run into.

Let me guess: you've got a regional starting tomorrow and you want to build a tracking system tonight? I wish you luck. It took us weeks to get a workable IR system, and that included access to our robot.

If you really want to do something autonomously, look at some of the simple state machine postings in this forum, and create a dead reckoning system of timed runs and turns. That's what most people are doing, anyway. If you don't have an IR system you will have plenty of company!

-norm