IMPROVING AN ULTRA-SONIC – BASED WALKING AID DEVICE FOR THE BLIND

Abstract

The electronic walking aid device using ultrasonic waves and warning of obstacles in Vietnamese was developed by our team in 2012. However, actual usage shows that the device still has false waring, because the ultrasonic sensor control algorithm is still limited. This study focuses on improving the algorithm to overcome false alarms. The hardware of the device is inherited, with the 89C2051 microcontroller, the SRF05 ultrasonic sensor modules and the Vietnamese alarm module using the ISD1420 chip. The embedded software on the microcontroller is integrated with a sensor error compensation function using the Levenberg-Marquardt non-linear least squares error algorithm. Testing experiments show that the improved algorithm can measure obstacle distances with over 96% accuracy, in useful distance ranges from 30 to 90 cm. Experimental results at the Blind Association of Can Tho City and the Blind Association of Duc Hoa District, Long An Province show that the device meets the expectations of the blind community, as well as giving them a lot of hope about a useful and low-cost product.