DirectMe

DirectMe is an indoor navigation system for visually impaired people. Utilizing Ultra Wide Band technology and using android application interface through smartphones, we created a method of guiding the visually impaired in indoor places where GPS is not accessible.

Motivation

Autonomous navigation is a crucial component for visually impaired people. Outdoors, positioning based on ubiquitous signals is feasible; however, for indoors, no universal positioning solution does exist. Due to the remarkably broad bandwidth, ultra-wideband (UWB) signs offer a proper multipath resolution and allow positioning with sub-meter (10 centimeter) accuracy. Also, because of the implementation of screen-reader software into mobile devices, visually impaired people nowadays can easily use smartphones. Having these two elements in mind, we decided to come up with a method of guiding blind people in indoor places.

System Overview

The position of the user is localized using UWB technology.There are 6-8 UWB anchors places in different positions of our testing indoor environment. The positions of the anchors along with the dimensions of the testing room (x,y,z) are hard coded. Using the position of the anchors and arrival time of signals communicated between UWB tag and the anchors, the technology allows us to calculate the user's position in the room. The wrist worn hardware prepared for the user has a 9 degree freedom absolute orientation sensor (BNO055). Data recieved from this sensor lets the system determine user's pose to correctly navigate him toward the desired destination. Pose and estimated position data are transmitted to our server using MQTT communication protocol. For the purpose of setting up MQTT connection our system uses a raspberry pi zero w as the broker.

The placement of UWB anchors

This image shows the layout of the room where we did our testings. The stars indicate the placement of our UWB anchors. However notice they were placed at various height levels which is not shown in the given 2D layout. Due to the instability of the signal provided by the UWB anchors placed by the TV and between the printer and monitor, those anchors were not used. It is believed the cause of this problem was related with their placement relative to other objects