karlok:
Hello,0.2 - 2 cm refer to the distance between the signal and the ground that is parallel to the signal's path. That's why I said in the title "attach an Ultrasonic Distance Sensor near the bottom". In the second picture, the light blue ray should depict the path of the ultrasonic signal which goes parallel to the bottom of the room. Is this also a problem?
And thanks for recommending the library.
I see now. Nope, won't be a problem. I've tested plenty of sensors located on the ground (mounted to a breadboard). However, the sound "beam" is not like the blue line (not a laser). It broadcasts like how sound comes out of a speaker (because that's what it is, a speaker). But, it only needs to get a ping back and the close placement to the ground is of no consequence as it's not at a right angle to get an echo.
In any case, this setup won't be a problem at all.
Tim