A great concept. I wouldn't have thought anyone here would imitate it (but if they do remember imitation is the greatest form of flattery).

I would recommend a combination of ultrasonic and ir sensors. Each has strengths and weaknesses based on the surface material and shape of the obstacle.

You also need to consider edge detection, and other than Lidar or really good video interpretation I don't have a good recommendation for that. The cane is used to detect the edge of stairs, sidewalks and train platforms as much as obstacles.

In the television program Covert Affairs, there is a blind character who uses a (purely fictional) handheld laser device instead of a cane. I could easily see something like that being used with sonar or ir sensors for better situational awareness. Have the vibration patterns change based on distance to the object pointed at rather than just on/off. if you build and patent this, I just want name credit. You can make all the money

ALan

Perhaps this is useful. I built a combination IR and ultrasonic radar turret that can also adjust the angle that it detects. Pretty simple https://www.youtube.com/watch?v=kbuQ-012bG4&feature=youtube_gdata_player