WE ALL KNOW that feeling – you are about to nod off and your head jolts forward, revealing your almost-nap to everyone else in the office, the lecture room or the conference hall.

Embarrassing.

But that little “micro-sleep” becomes more serious – and more dangerous – when you’re driving.

A driver fatigue alarm has just been put on the market to help reduce the number of road accidents caused by tiredness.

According to the Road Safety Authority, one in five crashes happen because the driver of the vehicle is overtired. Across Europe, about 4,000 people are killed each year because of driver tiredness.

A “micro-sleep” is defined as a brief, unintentional loss of attention which may involve nodding off or a blank stare for between two and 30 seconds.

The driver fatigue alarm, which is a motion sensor worn behind the ear, triggers an alarm if a driver’s head tilts forward. It is an early warning to tell the driver to pull over, take a rest and have a cup of coffee.

The alarms are already popular in Australia and were brought to the Irish market by Thomas Farrell. The alarm costs €29.95 but all profits raised through sales will be donated to Temple Street Children’s University Hospital.

There are two models – one which beeps loudly and another that just vibrates.

Maybe the silent one will be popular among students and tired office workers too?