I have come across magnetic print in various forms but was fairly uninspired by the implementation. The example I saw used the magnetic properties to turn a painted wall into a magnetic pin board. Nothing ground-breaking here.
Having been playing around with Bare Conductive paint for the last few weeks I considered combining a fine magnetic material with conductive ink as a possible solution to a problem I was facing with my internet connected paper prototypes. In short, I required an quick and accurate method of electrically coupling ardunio pins to conductive track printed on paper.
A quick browse on-line brought up Magnetite, a naturally occurring iron-oxide
Two days later a bag of this heavy powder arrived at my door.
As this was uncharted territory I experimented by mixing roughly one tablespoon full with an equal measure of bare conductive. I added a half a tea spoon of water to thin and after a quick mix with an old pencil sucked it up into a syringe and squirted it on the closest bit of paper I could find.
To my surprise, one it had dried, the new black cocktail was both wonderfully magnetic AND conductive.
As my tracks haven’t been drawn with any element of consistency I can’t account for any changes in track resistance relative to pure, dry Bare tracks. (Rawr!) In spite of this, my paper circuit conducted effectively. The resistive properties of Bare Conductive was a feature I was exploiting so additional resistance would actually be a bonus.
Using a syringe to both permanently store and accurately apply the ink has proved invaluable. The new compound will keep for a few months in this state.