We've already seen a number of systems designed to alert blind users to objects in their path, and most of those systems use cues such as audio tones or vibrations. A scientist at Germany's Karlsruhe Institute of Technology, however, has taken another approach. Florian Braun's "Proximity Hat" applies pressure to the wearer's head, in the direction of the obstacle.

The prototype version of the hat actually takes the form of a headband, equipped with six ultrasonic sensor modules. Each one of those makes 50 measurements per second, scanning horizontally in all directions over a distance ranging from a few centimeters up to several meters.

When a sensor detects an object in its path, it causes an accompanying elastic-encased pad to gently push against the crown of the wearer's head – the closer the obstacle, the harder it pushes. In this way, the person can ascertain both the direction and the distance of the item.

The system is claimed to be more intuitive than others, plus it leaves the user's senses of hearing and touch (on their hands) unaffected.

Besides its use in aiding the blind, it has also been suggested that the Proximity Hat could be used to guide firefighters through smoke-filled rooms, or even to assist workers who have to walk backward as part of their job. The pressure pads might additionally be used to warn sighted users of unseen hazards such as air pollution.