I am thinking of developing a Persistence of Vision Display. Hope you are familiar on that. No worries this article will quickly say you what..http://people.ece.cornell.edu/land/courses/ece4760/FinalProjects/s2012/jm787_dab355/jm787_dab355/index.html
There are many types of displays that looks like a wheel or cylinder but the basic thing is you need to rotate the lights. And of course you need power to the lights
So there are several approaches to provide power to the lights. Either you can include a battery in rotary part or you can use a set of "brushes" to supply the power to arduino. If you need to light them continuously the battery option is not feasible.
My question is how do you implement these brushes? I've once used a 3.5mm earphone jack and a socket to implement such requirement (Of course it won't work in this case). And yes I can use a barrel like conductor (I used a outer barrel of AV socket) on motor shaft with a copper brush as one terminal and the shaft of the motor as the other terminal. But doing these things practically is not much easy.
So I would like to hear about easier practical ideas. Is there some component that I can buy (say on ebay) to implement this requirement?