I experimented once with ultrasonic sensors and found them relatively complicated:
they have to be fixed very caryfully and embedded somewhere where no possible vibrations may occur, else there are wrong readings
dunno if the TTL-communication is really “a snap” ??? - to create pulses to trigger the signal and read back those pulses seems quite complicated to me (in terms of digitizing this signal … but I have no experience in that). IIRC I have seen an ultrasonic I2C device somewhere lately - can’t remember where - this would be a bit nicer, I guess…
All in all, I found the longest range (1.5 m; effective range ~1m) IR-Distance sensor a bit easier to deal with (so far) - but it’s just my 2c, I’d be interested to hear other experiences…
what about interferences with the audio signal ? These devices can sometime produce frequencies on the audible range.. do you own one? could you check that out ? thanks
i remember we had a tv remote control ultrasonic device at home during the 80s and my mother could change the tv program by washing metallic pots and you could clearly hear some very high frequencies while pushing the buttons