" DESIGN AND TESTING OF ULTRASONIC DISTANCE MEASURING SENSOR USING OPTICAL TRIGGERING_RU`QHbaYdHPJUL(egfUOQhNiPMjOQHbaYgk+LN`l[nmo[jLpOlfqr[jHPOs[ ctRU`Wur`l`QTVL_fHCY7HKJULvijLNw "