Do what gives you a buzz.

But having had your bright, fresh, original idea, the really hard part is turning it into a successful product. That's what takes all the sweat.

The notion that inventors are anorak-wearing crackpots with glasses held together with Sellotape is beguiling but wrong.

But there is only one person I blame for getting shafted, and that's myself. I went into the deal which I thought would secure the future of Orange Aids with culpable impetuosity. I had been used to doing business on a handshake and my work of honour, and I made the error of actually believing what the men in the pin-striped suits told me.

Ideas for gadgets for the disabled were coming into my head so fast they seemed to be arriving from somewhere outside of me, beamed down by an unremitting force. I had little control over them, or their flow. I would wake up in the middle of the night. A blinding flash of an idea would rouse me from my bed and I'd rush down to my workshop to have a go at it before the inspiration dimmed.

I'd work eighteen-hour stretches and fall asleep in my clothes. Then I'd wake up in the middle of the night, brew a pot of tea, and start work again. I was tired, but work had become pure enjoyment.

As long as you've got slightly more perception than the average wrapped loaf, you could invent something.