Hsu, Y.Y.HsuHsiao, S.-F.S.-F.HsiaoChiang, C.-E.C.-E.ChiangChien, Y.-H.Y.-H.ChienTseng, H.-W.H.-W.TsengTEI-WEI KUOAI-CHUN PANG2018-09-102018-09-1020061062922Xhttp://www.scopus.com/inward/record.url?eid=2-s2.0-34548142160&partnerID=MN8TOARShttp://scholars.lib.ntu.edu.tw/handle/123456789/331806This paper presents a system prototype to help elder persons being aware of changes in terrain ahead of them. Ultrasonic signal is used for the detection of terrain changes because of its stability in air transmission speed and its simplicity and cost in hardware designs. The prototype is designed and built using commercial-off-the-shelf (COTS) components with an 8051 microprocessor. It can detect obstacles of heights no more than 10 cm three steps away. © 2006 IEEE.Collision avoidance; Computer hardware; Cost reduction; Microprocessor chips; Stability; Systems analysis; Commercial-off-the-shelf (COTS); System prototype; Ultrasonic signals; Ultrasonic devicesconference paper10.1109/ICSMC.2006.3848082-s2.0-34548142160