New Scientist’s column ‘The Last Word‘ is often a great source of questions just waiting to become inventions.
I was inspired by it today to think about a pen which maximises the lifetime of its ink supply, without greatly diminishing legibility.
Today’s invention is therefore a pen incorporating a tiny inkjet printer with one printhead and a small camera.
As the pen is moved across the surface of the paper, it spits out dots at a uniform rate.
When the camera detects that the pen is changing direction or printing near other dots, it increases its print rate. In this way, sections of straight line, where the information content per dot is low, are represented by small amounts of ink -and vice versa.
(You might build a version with the background dot rate proportional to the acceleration, as determined by a small on-board sensor)