I found this "tip" while researching setups from other robot projects and thought it was interesting. If you are using a sr04 ultrasonic sensor it reads the first ping it receives after the trigger pulse and stops. With this setup once the first ping is received it is recycled as a trigger to a second sensor. The second sensor tx must be muted (covered with tape) and the second sensor reads the echo from the back ground. This is for identifying edges of large objects and doorways.
Any suggestions or thoughts are appreciated I just found this interesting and I will add sketches to illustrate what I'm talking about.
I don't know how the script would be written to utilize edge information but it does seem like this could be useful to inform the robot this is a possible doorway or an object it can go around and not just perceive it as a wall to completely avoid. Thanks guys.