Using 2 sonar range finders to find distance inbetween

Hey all,

I’m trying to build a robot that follows a human.

The human would have a sonar transmitter on their belt, and the robot would have a sonar transmitter on its front.

The robot’s sonar would send a signal, S1, which the human’s sonar would receive, the human’s sonar would then send a different signal, S2, back to the robot’s sonar.

The robot would then process the time difference between sending S1 and receiving S2 to calculate the distance.

Is it possible doing this with the Pololu sonar range finder or the ultrasonic range finder?

Any help would be greatly appreciated!

That is a good idea, but the cheap sonar range finders on the hobby market don’t allow you to have any control over the signal that you send (other than when to send it). All the ones that I know about send a “ping” when activated, then return a timed pulse or an analog or digital value to the controlling computer, representing the distance to the nearest reflecting surface.

You can buy the sonar transducers very cheaply and build your own circuit to generate signals, but an important question is how to make the two signals unique and easy to decode. Here are a couple of examples of DIY rangerfinders. There are lots more. … angefinder … anger.html