Comment by mltony

I got the idea when I was learning to cross a wide street with a white cane. three lanes in each direction - and it proved to be a challenge because I would veer left or right and frequently get confused and lost. Then I thought a compass would be helpful, but a quick survey of compass apps on iOS showed that they are either visual, or show your heading as a number that can be read by VoiceOver, but it is still not very practical. So I thought that I need to encode heading as something that my brain can easily decipher during crossing the street. I have prior musical training, so that's why I decided to encode heading as a musical interval. This allows my app to communicate with about 10 degrees precision and in practice this is well enough to go on a straight line for long enough to cross the street.