WT81B003-0202 (Ultrasonic long distance sensor)
From Bambi
The Waytronic WT81B003-0202 18m (see [1]) should be able to provide distance measurements at least every 250ms up to 18m with a tolerance of +-10cm.
It can be set in various operation modes, one of those communicates through a standard serial protocol (9600/8-N-1). Using an Arduino board equipped with an uart port it's possible to test the sonar performance. The sketch can be found at https://mega.nz/#F!Bo8jHabQ!kwxQR5jFZorFaOLdQKsTdw)
Datasheet
The original datasheet is in Chinese, the following version was translated with Google Translate:
