Have you ever woken up in the morning after a night on the tiles and wondered if it's safe, or legal, to drive? Seán O'Sullivan, the technology investor and star of Dragons' Den, is funding the launch of a smartphone app to test your blood alcohol limit. DrnkAngel basically turns your iPhone into a breathalyser.

O'Sullivan says he was talking to Boots, the pharmacy chain, when they told him of a new product in development that needed finance.

“They said it wasn’t ready but they wanted to carry it when it was, and suggested we talk to them,” he said.

SOSventures, his Cork-headquartered investment firm, took a minority stake in Smart Ecosystem, the UK-Italian firm behind the app, which will not be available until next spring.

DrnkAngel consists of an app along with a little piece of hardware that plugs into your phone’s audio jack – essentially a pipe for users to blow into.

Blow on the pipe, and the app gives results including your blood alcohol level, and whether you are over or under the drink-driving limit depending upon your location settings.

Its developers are currently running an Indiegogo online campaign to raise more cash. Judging from some punters’ reactions to the product when asked to test it – a series of Youtube ads is doing the rounds – it looks like DrnkAngel could also be a hit among boozers who want to measure just how plastered they and their friends are while out on the town.

O’Sullivan says he doesn’t drink much himself because “it makes me slow in the mornings”. Alas, it has that effect on most of us, Seán.