A hairbrush that helps you rate a 'bad hair day'!

A new Japanese hairbrush may soon be able to help hairdressers work out the appropriate treatment for a person in their care, as it will be able to quantify the damage caused by treatments such as hair dyes and bleaches.

Thanks to Japan's Kao Corporation it would soon be possible to rate a ‘bad hair day’ on a scale of 1 to 10.

The hairbrush would be able to analyse the sound while hair is brushed revealing the state of the hair, according to five inventors from the company.

The brush contains an aluminium bar, which is polished, sandblasted and then buried amongst its prongs. A microphone is attached to the bar that picks up vibrations as hair is dragged over the bar. A built-in strain gauge also records the resistance caused by brushing, reports New Scientist.

A USB connection then feeds these measurements to a PC which compares the sound and the pulling strain.

Tests carried out in a Tokyo hair salon showed that hair in good condition makes far less noise than dirty hair with split ends.

Loud sound at high frequencies also indicates too much bleaching, the inventors said.