Drinking time: breathalyzer watch can tell how drunk you are

The latest timepiece from watchmaker Tokyoflash Japan comes with a built-in breathalyzer and “sobriety game” to test how drunk you are.

When the wearer blows into a sensor hidden in a side panel of the Kisai Intoxicated watch the screen changes color depending on the level of alcohol detected - green means you're sober, yellow means you're “buzzing” or tipsy and red means you're drunk.

The sobriety game also tests your reaction times to an onscreen challenge to see if you're over the limit.

Readings are based on the blood alcohol content (BAC) detected in the wearer's breath.

To use the sensor, press the alcohol button on the right-hand side of the watch.

The Japanese company is quick to claim the watch is just for fun and is more of a 'party trick' than a scientific test.

The built-in sobriety game has a vertical bar that moves from left to right on the display.

To pass the test, the wearer must stop the bar when it is in the centre of the screen.

The watch is made of stainless steel and weighs around 160g.

It is water resistant and comes with a rechargeable battery.

In March, a company from San Francisco released the Breathometer - a breathalyzer that plugs into a mobile phone to give owners an instant BAC reading.

The gadget pugs into the headset jack of an iPhone or Android handset and its makers say it allows owners to check their alcohol level wherever they and - and claim it could even be used to choose who should drive.

In April, the BACtrack mobile breathalyzer app was released that can automatically post BAC levels to Facebook or Twitter.

Critics claimed the mobile breathalyzer could encourage drinking games but the firm behind it claims it will help users “understand how alcohol affects their body.”

Users can even create a drink diary of their evening, with pictures of every drink and how it affected their blood alcohol level and users’ readings are shown on a 'world drinking map'.