WT81B003-0202 (Ultrasonic long distance sensor)
The Waytronic WT81B003-0202 18m 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:
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