hey guys, i'm new to this forum and wanted to join forum. I had an idea to use a regular sized pen as an IR pen but AAA batteries dont fit in the case of the pen, i want to make the IR pen portable and store the power supply within the pen case. I am wondering what type of battery i should use. I noticed there were "coin" batteries that exsisted but i'm not sure how many i would need and how to store the batteries within the pen. You expertises and help would be greatly appreciated!