This paper presents a novel electronic travel aid, called iSONIC, which can help a visually impaired person walk around more safely. Attached to a conventional white cane, the iSONIC detects obstacles at head-height that cannot be covered by a traditional cane and gives warnings in the forms of vibration or sound to avoid dangerous situations. We developed an algorithm to restrict the sensing range to reduce confusing and unnecessary detections and a method to remove the sensing errors due to the impact of ground tapping. In addition to obstacle detection, the iSONIC give information of object color and the environmental brightness when the user wants to know.