Ultrasonic Problem

I wondered if this range finder was like those used in the Lego robots, so I looked it up. Here's what I found, which is probably information you already have.

Do you have to do this in hardware?

Do I understand that your buggy has to locate and approach another range finder (probably using its own range finder to sense the signal from the other)? Is this within a competition field of some sort? Otherwise, if the other range finder is facing away from your buggy, your buggy might have to do a lot of meandering to pickup any signal at all from the other range finder.

I'm not so familiar with your hardware but I have a few ideas.

If the terrain is flat, you could use two sensors, one on each side or side-by-side (separated by an inch or so). You program your thingy so that if the ultrasonic pulse reaches one sensor ahead of the other, then the source must be from that direction. If the pulses arrive at the same time, then the source must be dead ahead. It's the same principle that we humans use (via the ears).

If the terrain is not flat, you could use a minimum of three sensors, arranged in a triangle. The third sensor provides some sensing in the vertical axis. You just tell the buggy to go toward the sound depending on which sensor gets hit first.

'Hope this helps (that is, if you haven't thought about it already).

a set of in the ear speekers from a $1 radio set at a right angle might work for the sensors. then the detection circuit would have to detect your Ultrasonic signal.