I'm assuming (maybe wrongly and naively) that those are already solved problems. I'm assuming a visually impaired person already has his/her routines to avoid those problems. That's why I wanted to hear from the users of the app. For example, a volunteer who helped someone.

Here's an example from real life (in person, not via this app).

I have a buddy who is blind. In the US, paper currency is all the same size and shape, so it's impossible to distinguish them by feel alone. He uses a system of folds to remember which bill is which, but if he drops one, or the cashier doesn't tell him what the denominations are, etc..., he ends up not know which bill is which. Occasionally that means he has to ask someone, despite having a 'routine' that is generally very effective.

This iOS currency recognition app is accurate and easy to use. If only more visual recognition apps were this easy, or there was an open-source recognizer library for this functionality:

http://www.looktel.com/recognizer

There are scanners that a blind person can keep in their pocket or on a keychain that will scan currency and speak the denomination.

http://www.orbitresearch.com/ibill_details.php

iBill® Talking Banknote Identifier, $119 with free shipping.

Well I have helped someone, find the right CD. The examples mentioned are all from usages of the app.

The idea for the app came from Hans Jørgen Wiberg who himself has tunnel vision. He worked for the danish blind society, where he taught blind people to cook. One thing he often heard was "If only I could have a pair of eyes a few minutes a day..." He also knew of blind people who used facetime to connect to their loved ones. But the good thing about this concept is that you just say "Thank you" and disconnect and you are done with it, you don't owe someone a favour.