Navilens is an alternative to QR codes which the producers clainm is a much
more rugged system offering the ability to read the codes at a far greater
distance.

Around the house and garden Navilens has a part to play along side Braille and
other tagging systems such as the RNIB pen friend.

Buildings could be easily labelled and thus navigated using the Navilens system,
the ability to read the larger labels at 40 to 50 feet is useful - think of 
such things as lifs, stairs, fire exits being 'visible' to the blind from
as far as 50 feet.

Developed for labelling items and buildings.

The Navilens app is available for both Android and apple devices.

Pricing - appears free for personal use.

A few links to the Navilens project including YouTube clips:-

More coming

a4 = So far 7m - much more to do
10mm - up to 1m +/-
23mm - ?
Degree checking to be added!

* How to share personal codes between devices; backup and copy.
* Use of electronic photo frames to display codes, can changing codes be detected
  without moving device?
* power drain?