mySmartCane: Giving Freedom to Visually Impaired People

[Vasileios.T]

Hacking the old fashioned white cane to bring it up to date with just a single sensor, providing audio feedback of any close-by obstacles.

The Inspiration

Being raised up by my mother who has retinitis pigmentosa, I have experienced the struggle of the visual impaired people when they try to navigate with the white cane. The white cane even though, a simple and marvellous invention, is now stuck in the past. This project gave me the opportunity to brainstorm and challenge the current situation. More advanced canes exist but their price tag makes them exorbitant.

About the Developer

My name is Vasileios Tsormpatzoudis, Vas, a student at the University of Manchester studying Electrical and Electronic Engineering. I am a motivated engineer who desires to make the world a better place to live.

Implementation

Reading the ultrasonic sensor is similar to reading an analogue output. Some simple maths are implimented on the myRIO to condition & process the signal. For example, to improve the accuracy of the low-cost ultrasonic sensor, I implemented an averaging algorithm on the myRIO, which returned the mean 'object distance' of the past 10 samples. This improved object distance value is used to generate a series of audiable 'chirps' - whose frequency coralates with the detected distance.

Additionally, the code compares the object’s distance with user configurable 'maximum distance' limit. By default, the maximum distance is 50 cm, as the average step of a person is 35 cm and hence anything above 50 is a bit redundant.

The 3D enclosure

My colleague Jake Akhtar designed a quick enclosure which will house the ultrasonic sensor at the bottom of the cane. You may find the CAD files below.

Requirements

Software

• LabVIEW 2015

Hardware

• myRIO
• Maxbotix LV – MaxSonar – EZ2

Steps to Execute the Code

• Connect the myRIO to a PC via USB.
• Wire the sensor as displayed above.
• Power the myRIO either by connecting the power supply that comes with the myRIO or using an external battery.
• On the PC, unzip the ‘mySmartCane_SingleAudio.zip’.
• Open ‘mySmartCane_SingleAudio.lvproj.' and then double click on the ‘RT_main.vi’ found under the myRIO and make sure that you have the correct IP selected.
• Run the 'RT_main.vi' which will automatically deploy to the myRIO.
• The code will start running automatically.

Next Steps

The modular, software-defined nature of the system would allow me to easily add the folloring features:

• A known disadvantage of the white cane is the fact it is not detecting overhead obstacles, such as road signs. This can be tackled with adding a second ultrasonic sensor which will point to the head level of the user. By this way, the myRIO will be able to notify the user for any obstacles overhead obstacles. Beware, as the height of every user differs, this sensor will require additional calibration.
• An extra feature I wanted to include at this project is 3D audio feedback. This functionality can be added by using an accelerometer sensor, so the myRIO will have an understanding on when the user changes the direction of the cane and hence adapt the sound level on each ear. This feature can minimise the user’s freedom as he will need to use two headphones. Bone conductive headphones can be selected for this feature.
• An ambitious feature is the use of a GPS sensor to log any overhead obstacles, similar to this . A database can allow users to plan their trips much easier as well as navigate without any accidents.