I had a friend - something of an inventor and a BBC Micro fan - who used to take long walks on moorland and always found himself besieged with ideas that he wanted to note down. Obviously, a pencil and a notepad would not do, so he started work on a rig that would involve a MicroWriter stuffed into his coat pocket (he’d already taught himself to use it), ‘some sort’ of computer (I think he was imagining a portable version of a Beeb) and a head-up display attached to the peak of his hat. That way, he could think, make notes and watch where he was walking all at once. This was in the early/mid-80s so, suffice to say, he was well ahead of the necessary technology and it went nowhere.
He was always ahead of the curve. He also invented a magnetically triggered automatic cat flap long before such things came onto the market. Alas, it needed quite a strong magnet and his wife made him abandon it when the cat was found stuck to its food bowl.