More from the interview

The interview with Mike, a partially-sighted cane user, was very helpful in redirecting the development of our product.

First of all he told us that for some people keeping a guide dog simply isn't practical due to their lifestyles. Mike is a student who works in hospitals and goes out a lot in the evenings. Leading a fairly hectic lifestyle and living in the city too, all makes it rather "unfair on the dog" as he put it.

He described his cane in detail. It sounds like an incredibly well-designed and simple piece of equipment. Emulating this in our device will be a challenge!.

Positive aspects:

• The rolling tip at the end is useful as the cane can be dragged across the floor rather than tapping.
  
• Three dimensions of movement allows excellent perception of the surface in front.
  
• It's got a comfortable rubber grip.
  
• It folds up very small to a pocketable size.
  
• It's light.
  

Negative aspects:

• The cane bends quite easily, particularly if the user is walking fast and hits something hard with the cane. This is a trade-off between strength of the material and the weight of it. Our device will have to be light as the user will not appreciate lugging something cumbersome around!
  
• The tip can get stuck in cracks or holes in the pavement, causing sudden stopping of movement and maybe even jabbing the stick into the user's stomach.
  

We asked Mike how important it is to him to know the surface he's walking on. He said it is very important - his depth perception is poor and he needs to know if there are steps in front for example. It's useful also to know the gradient of the ground. If he suddenly reaches a quick drop-off or hill it can unbalance him or cause him to stumble. Actual texture of the surface is not quite so important, but still helps with balancing. If there are steps in front and you're not aware of it, that's the easiest way to break a hip!

Our original idea for a hand-held device using force feedback to guide the user as a replacement for a cane or dog looks like it will be lacking in this key area of ground perception as the cane allows incredibly simple and effective three-dimensional perception. Our device would only provide two-dimensional information and omits the depth thing completely. So at the very least we have to use the device alongside an existing cane or dog.

With this in mind, Mike was also critical of the idea of having to hold the device in your hand as with a cane in one and the device in the other, you have no free hands to push your trolley or carry your shopping. As Dan said earlier, a device attached to the user or possibly to the cane will be necessary.