Smart stick for visually impaired
This project article from 4D Systems describes how to build a smart stick that uses sonar to guide visually impaired. It uses 4Duino, which is an Arduino compatible computer board with built in 240×320 resolution TFT LCD Display and Wi-Fi capabilities. The stick consists of three ultrasonic sensors that can sense obstacles in three directions (left, right and front) within a distance of 400 cm. When an obstacle is detected within the range, the user is notified with the activation of a vibration motor. Because 4Duino is WiFi enabled, the user can also send text messages to a web browser for help in emergency situations by simply tapping the TFT screen.