As if looking at your hair’s horribly tangled mess is not enough, Japan’s Kao Corporation’s smart hairbrush further rubs it in by letting you rate a “bad hair day” on a scale of 1 to 10.

The hairbrush analyzes the damage caused by hair treatments such as hair dyes and bleaches by “listening” to the sound as hair is brushed.

“To make the brush, an aluminium bar a few micrometers long is polished and sandblasted and then buried amongst the prongs of the brush. A microphone attached to the bar then picks up vibrations as hair is dragged over the bar. A built-in strain gauge also records the resistance caused by brushing".

A USB connection 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 say. The brush could help hairdressers work out the appropriate treatment for a person in their care.”

Link viaNew Scientist